−---
−title: Panelboards
−category: Electrical
−toc_depth: 3
−description: >
− When to use: Dead-front panelboards rated 1000 V or less for commercial, institutional, and light-to-medium industrial facilities - lighting and appliance branch-circuit panelboards and power distribution panelboards, whether installed as service entrance equipment or as sub-distribution points fed from switchgear, switchboards, or larger panelboards. Covers single-phase and three-phase configurations, main breaker (MCB) and main lug only (MLO) types, surface-, flush-, and floor-mounted enclosures indoors and outdoors from 100 A through 1200 A main bus, and the branch-circuit overcurrent devices, surge protection, metering, and identification furnished within.
−
− Not intended for: Low voltage metal-enclosed switchgear or switchboards (see [[sync/low-voltage-switchgear]], [[sync/low-voltage-switchboards]]), motor control centers (see [[sync/motor-control-centers]]), enclosed safety switches and fused disconnects (see [[sync/enclosed-switches-and-disconnects]]), medium voltage equipment above 1000 V (see [[sync/medium-voltage-switchgear]]), residential load centers, or equipment in hazardous classified locations without application-specific modifications.
−---
−
−# Scope {toc}
−
−## This standard covers the materials, construction, ratings, installation, testing, and identification requirements for dead-front panelboards rated 1000 V or less, including lighting and appliance branch-circuit panelboards and power distribution panelboards. {note}
−
−## A panelboard is a single panel or group of panel units designed for assembly in the form of a single panel, installed in a cabinet or cutout box and accessible only from the front, that includes buses and overcurrent devices for the control of light, heat, or power circuits. Dead-front construction leaves no energized part on the operating face once the trim is installed. {note}
−
−## Panelboards are by definition equipment rated 1000 V or less under NFPA 70 Article 408 and UL 67, so no separate low-voltage qualifier is carried in the title or the scope. {note}
−
−## Equipment shall comply with UL 67 (Panelboards), shall be listed and labeled by a Nationally Recognized Testing Laboratory (NRTL), and shall be installed in accordance with NFPA 70 Articles 110, 230, 240, 408, and all applicable articles governing the connected loads.
−
−## Assemblies Covered {toc}
−
−### Panelboards covered by this standard are dead-front assemblies with an enclosed bus structure and individual branch circuit overcurrent protective devices installed or provided for installation by the Contractor. {note}
−### They serve the function of subdividing a feeder or service into branch circuits, providing overcurrent protection for each branch circuit, and in main breaker configurations, providing a means of simultaneously disconnecting all ungrounded supply conductors. {note}
−
−### The terms "lighting and appliance branch-circuit panelboard" and "power panelboard", and the associated limit of 42 overcurrent devices in a single cabinet, were removed from NFPA 70 Article 408 in the 2008 edition. The terms remain in common usage and appear in older project documents, but they no longer carry code consequences and are not used as a basis for any requirement in this standard. {note}
−
−### For assemblies employing drawout power circuit breakers and designed for higher fault duty, see [[sync/low-voltage-switchgear]].
−
−### For assemblies designed as distribution switchboards with higher bus ratings and front-accessible wiring troughs, see [[sync/low-voltage-switchboards]].
−
−### For enclosed safety switches, fused disconnects, and non-automatic disconnecting means, see [[sync/enclosed-switches-and-disconnects]].
−
−### Residential-grade load centers, tested to the consumer-product provisions of UL 67 and supplied as dwelling-unit service and distribution equipment, are outside the scope of this standard. {note}
−
−## Related Systems {toc}
−
−### Service entrance equipment and downstream panelboards shall be grounded and bonded per [[sync/grounding-and-bonding]].
−
−### Feeder and branch circuit conductors shall comply with [[sync/conductors-and-cables]].
−
−### Raceways and conduit systems entering panelboards shall comply with [[sync/raceways-and-conduit]].
−
−# Referenced Standards {toc}
−
−## Equipment, materials, and installation shall comply with the latest adopted edition of the following standards and codes.
−
−## Where conflicts exist between referenced standards, the more stringent requirement shall govern unless the Engineer of Record directs otherwise in writing.
−
−## The adopted edition of the National Electrical Code varies by jurisdiction; the edition enforced by the Authority Having Jurisdiction is the one that governs, and confirming it before fabrication avoids building to a superseded article number. {note}
−
−| Standard | Title |
−|----------|-------|
−| NFPA 70 | National Electrical Code (Articles 100, 110, 210, 215, 220, 225, 230, 240, 250, 285, 408, 700) |
−| NFPA 70E | Standard for Electrical Safety in the Workplace |
−| UL 67 | Standard for Panelboards |
−| UL 50 | Standard for Enclosures for Electrical Equipment (Non-Environmental Considerations) |
−| UL 50E | Standard for Enclosures for Electrical Equipment (Environmental Considerations) |
−| UL 489 | Standard for Molded-Case Circuit Breakers, Molded-Case Switches, and Circuit-Breaker Enclosures |
−| UL 1053 | Standard for Ground-Fault Sensing and Relaying Equipment |
−| UL 1699 | Standard for Arc-Fault Circuit-Interrupters |
−| UL 943 | Standard for Ground-Fault Circuit-Interrupters |
−| UL 1449 | Standard for Surge Protective Devices |
−| NEMA PB 1 | Panelboards |
−| NEMA PB 1.1 | General Instructions for Proper Installation, Operation and Maintenance of Panelboards Rated 1000V or Less |
−| NEMA 250 | Enclosures for Electrical Equipment (1,000 Volts Maximum) |
−| NEMA AB 1 | Molded Case Circuit Breakers, Molded Case Switches and Circuit Breaker Enclosures |
−| NETA ATS | Acceptance Testing Specifications for Electrical Power Equipment and Systems |
−| IEEE 1584 | Guide for Performing Arc-Flash Hazard Calculations |
−| IEEE 519 | Recommended Practice for Harmonic Control in Electric Power Systems |
−
−# Submittals {toc}
−
−## Action Submittals {toc}
−
−### Contractor shall submit the following for Engineer's review and approval prior to procurement:
−
−- Shop drawings for each panelboard showing enclosure dimensions (height, width, depth), front elevation indicating device positions, bus configuration, and conduit entry areas
−- Panel schedules for each panelboard, including circuit numbers, circuit descriptions, pole counts, breaker frame sizes, trip ratings, and bus rating
−- Catalog data sheets or product data for the panelboard assembly and all overcurrent protective devices, including AFCI and GFCI breakers where specified
−- Catalog data confirming UL 67 listing and, for service entrance equipment, UL 67 service entrance listing
−- Short-circuit current rating (SCCR) documentation confirming that the assembly rating equals or exceeds available fault current at the point of installation
−- Where series ratings are applied per NEC 240.86, documentation of the tested series combination, including the upstream device type and rating
−- Surge protective device (SPD) product data where SPDs are factory-installed or provided for field installation
−- Seismic certification documentation where required by the applicable building code
−- Selective coordination study sealed by a registered professional engineer, where the panelboard serves an emergency, legally required standby, or critical operations power system
−- Arc flash incident-energy calculations performed in accordance with IEEE 1584, where an arc flash study is required by the Owner or the Authority Having Jurisdiction
−
−```datasheet
−label: Submittal Documentation
−type: checkbox
−options:
− - "Shop drawings (dimensions, front elevation, conduit entry)"
− - "Panel schedules (all circuits, ratings, descriptions)"
− - "Product data / catalog sheets"
− - "UL 67 listing confirmation"
− - "SCCR documentation"
− - "Series rating documentation (if applicable)"
− - "SPD product data (if applicable)"
− - "Seismic certification (if required)"
− - "Selective coordination study, PE-sealed (if required)"
− - "Arc flash incident-energy study per IEEE 1584 (if required)"
−default:
− - "Shop drawings (dimensions, front elevation, conduit entry)"
− - "Panel schedules (all circuits, ratings, descriptions)"
− - "Product data / catalog sheets"
− - "UL 67 listing confirmation"
− - "SCCR documentation"
− - "Series rating documentation (if applicable)"
− - "SPD product data (if applicable)"
− - "Seismic certification (if required)"
− - "Selective coordination study, PE-sealed (if required)"
− - "Arc flash incident-energy study per IEEE 1584 (if required)"
−```
−
−### Panelboard fabrication shall not begin and materials shall not be ordered until submittals are returned as reviewed.
−
−## Closeout Submittals {toc}
−
−### Contractor shall provide at substantial completion:
−
−- Record panel schedules reflecting all as-installed circuit assignments, updated to reflect any field changes from the contract documents
−- Operation and maintenance manuals for the panelboard assembly and installed accessories
−- Factory test reports (where witnessed or certified testing is specified)
−- Field acceptance test reports
−- Warranty documentation
−- Spare parts inventory with manufacturer part numbers
−
−```datasheet
−label: Required Closeout Submittals
−type: checkbox
−options:
− - "Record panel schedules (as-installed circuit assignments)"
− - "Operation and maintenance manuals"
− - "Factory test reports"
− - "Field acceptance test reports"
− - "Warranty documentation"
− - "Spare parts inventory with manufacturer part numbers"
−default:
− - "Record panel schedules (as-installed circuit assignments)"
− - "Operation and maintenance manuals"
− - "Factory test reports"
− - "Field acceptance test reports"
− - "Warranty documentation"
− - "Spare parts inventory with manufacturer part numbers"
−```
−
−# Quality Assurance {toc}
−
−## Manufacturer Qualifications {toc}
−
−### Panelboards shall be manufactured by a company with documented experience producing UL 67 listed panelboard assemblies.
−
−### The bus structure, interior assembly, and overcurrent protective devices shall be produced or furnished by the panelboard manufacturer as a coordinated assembly.
−
−### Field assembly of panelboards from separately sourced bus structures, enclosures, and breakers by the Contractor is not acceptable unless specifically authorized by the Engineer.
−
−### Manufacturer shall maintain a technical service organization capable of providing field support and replacement parts.
−
−## Source Limitations {toc}
−
−### All panelboards of a given type on a single project shall be from one manufacturer to ensure spare parts interchangeability, consistent training requirements, and coordinated technical support.
−
−### Mixing manufacturers for the same panelboard product category within a project requires written approval by the Engineer.
−
−## Installer Qualifications {toc}
−
−### Panelboard installation shall be performed by a licensed electrical contractor and journeyman-level electricians experienced in the installation of low voltage distribution equipment.
−
−### Personnel performing field acceptance testing shall be employed by a firm regularly engaged in testing electrical power equipment, with testing technicians certified at a minimum to NETA Level II.
−
−## Regulatory Requirements {toc}
−
−### Panelboards and their installation shall comply with all applicable federal, state, and local codes and ordinances, including the adopted edition of NFPA 70 and any state or local amendments.
−
−### The Authority Having Jurisdiction (AHJ) shall be notified of work as required and all work shall be subject to inspection by the AHJ.
−
−### Obtain all required permits prior to beginning installation.
−
−### Field modifications that alter the panelboard listing, including cutting additional openings in a NEMA 3R, 4, 4X, or 12 enclosure and installing components not listed for the assembly, are prohibited.
−
−### A field modification that voids the listing removes the basis on which the Authority Having Jurisdiction accepts the equipment, and the resulting rework is invariably charged to the party that made the cut. {note}
−
−# Environmental and Service Conditions {toc}
−
−## Panelboards shall be suitable for continuous operation under the ambient conditions at the installation site.
−
−## Where site conditions differ from standard rating conditions, equipment shall be derated per the manufacturer's published derating tables.
−
−## Ambient Temperature {toc}
−
−### The design maximum ambient temperature at the installation shall be as indicated in the datasheet.
−
−```datasheet
−label: Ambient Temperature (Maximum)
−type: range
−unit: '°C'
−options:
− min: 40
− max: 55
− setpoints: [40, 50, 55]
−default: 40
−```
−
−### Standard UL 67 temperature rise tests are conducted at 40°C ambient.
−
−### Equipment installed in locations with sustained ambient temperatures above 40°C shall be derated or an oversized assembly shall be specified.
−
−### Common elevated-temperature locations include rooftop mechanical rooms, non-air-conditioned warehouses, and equipment rooms in hot climates. {note}
−
−## Altitude {toc}
−
−### The installation altitude shall be as indicated in the datasheet.
−
−```datasheet
−label: Installation Altitude
−type: select
−options:
− - "Below 6,600 ft (2,000 m) — No derating required"
− - "6,600 – 9,900 ft (2,000 – 3,000 m) — Derating required, consult manufacturer"
− - "Above 9,900 ft (3,000 m) — Special design required"
−default: "Below 6,600 ft (2,000 m) — No derating required"
−```
−
−### At altitudes above 6,600 ft (2,000 m), reduced air density decreases the dielectric strength of air and impairs the cooling of enclosed equipment. {note}
−
−### Derating requirements shall be obtained from the manufacturer and documented on the contract drawings.
−
−## Installation Environment {toc}
−
−### The location of each panelboard shall be [[drawing: as indicated on the electrical plans]].
−
−### The installation environment is drawing information rather than a product decision; the product decision it drives — the enclosure NEMA rating — is specified in the Enclosure section. {note}
−
−## Seismic Requirements {toc}
−
−### The seismic certification basis shall be as indicated in the datasheet.
−
−```datasheet
−label: Seismic Certification
−type: select
−drawing_ref: "structural drawings"
−options:
− - "Not required"
− - "IBC/ASCE 7 — Importance Factor 1.0"
− - "IBC/ASCE 7 — Importance Factor 1.5 (essential facility)"
− - "OSHPD pre-approval required (California healthcare)"
−default: deferred
−```
−
−### The Seismic Design Category and Importance Factor are established by the project's structural design; the electrical scope adopts them rather than setting them. {note}
−
−### Where required by the applicable building code (IBC, CBC, or state-adopted equivalent), panelboards shall be seismically certified for the project's Seismic Design Category.
−
−### Seismic certification shall be by shake-table test or by analysis per ASCE 7.
−
−### Seismic anchorage details shall be included in the shop drawing submittals and shall be coordinated with the structural drawings.
−
−### Anchor bolts, housekeeping pad dimensions, and seismic restraints shall be installed per the manufacturer's certified installation instructions.
−
−# Electrical Ratings {toc}
−
−## System Voltage {toc}
−
−### The system voltage and configuration shall be as indicated in the datasheet.
−
−```datasheet
−label: System Voltage
−type: select
−drawing_ref: "panel schedule"
−options:
− - "120/240V 1Φ 3-wire"
− - "120/208V 3Φ 4-wire"
− - "277/480V 3Φ 4-wire"
− - "480V 3Φ 3-wire"
− - "120/240V 3Φ 4-wire (delta, center-tapped)"
−default: deferred
−```
−
−### The number of phases and the number of wires are fixed by the system voltage selected, so they are not offered as separate selections. {note}
−
−### The system voltage shall match the serving feeder or service voltage.
−
−### Where the panelboard is fed from a transformer secondary, verify that the panelboard voltage rating matches the transformer secondary voltage configuration.
−
−### Consult the Engineer when 480V delta systems or 120/240V center-tapped delta systems are encountered, as these systems have specific grounding and breaker requirements.
−
−## Main Bus Rating {toc}
−
−### Main bus continuous current rating shall be as indicated in the datasheet.
−
−```datasheet
−label: Main Bus Ampere Rating
−type: range
−unit: A
−drawing_ref: "panel schedule"
−options:
− min: 100
− max: 1200
− setpoints: [100, 125, 150, 200, 225, 250, 400, 600, 800, 1000, 1200]
−default: deferred
−```
−
−### Bus rating shall be selected to carry the calculated demand load with adequate capacity for future circuit additions.
−
−### Bus rating shall not be less than the main overcurrent device rating.
−
−### Bus ratings of 225A are the most common configuration for commercial lighting and branch-circuit panelboards; power distribution panelboards serving large mechanical, elevator, or process loads typically require 400A to 1200A bus ratings. {note}
−
−### Ratings above 1200A are generally better served by switchboards or switchgear — see [[sync/low-voltage-switchboards]] or [[sync/low-voltage-switchgear]]. {note}
−
−## Short-Circuit Current Rating {toc}
−
−### The panelboard short-circuit current rating shall be as indicated in the datasheet.
−
−```datasheet
−label: Short-Circuit Current Rating (SCCR / AIC)
−type: range
−unit: kAIC
−drawing_ref: "panel schedule"
−options:
− min: 10
− max: 100
− setpoints: [10, 14, 18, 22, 25, 35, 42, 65, 100]
−default: deferred
−```
−
−### The panelboard short-circuit current rating (SCCR), also called the available interrupting capacity (AIC) rating, shall equal or exceed the maximum available fault current at the panelboard line terminals.
−
−### Available fault current shall be determined by a short-circuit study based on confirmed utility available fault current, transformer impedance, and feeder conductor impedance.
−
−### The SCCR stamped on the assembly shall be the lowest-rated component in the assembly.
−
−### Fully-rated panelboards, where every breaker is individually rated for the assembly SCCR, are required at service entrance locations and at first-downstream distribution points where fault current is high.
−
−### Series-rated assemblies, where the combination of a higher-rated main breaker and lower-rated branch breakers is tested as a system, are permitted per NEC 240.86 at downstream locations where the available fault current at the panelboard terminals has been reduced by the impedance of the feeder.
−
−### Additional requirements for series-rated assemblies are addressed in the Series Rating section. {note}
−
−### A value of 22 kAIC is common for downstream 208V commercial branch-circuit panels; verify the available fault current at each panel location before selecting this rating. {note}
−
−## Service Entrance Equipment {toc}
−
−### Whether the panelboard is service entrance rated shall be as indicated in the datasheet.
−
−```datasheet
−label: Service Entrance Equipment
−type: radio
−drawing_ref: "one-line diagram"
−options:
− - "Service entrance rated (main service panel)"
− - "Distribution panel (downstream of the service)"
−default: deferred
−```
−
−### Where the panelboard serves as the building's main service entrance equipment, it shall be listed and labeled for use as service entrance equipment per UL 67 and shall comply with NFPA 70 Article 230, including provisions for service disconnecting means, service conductor terminations, metering socket (where utility-metered), and available fault current labeling.
−
−### Service entrance rated panelboards shall include a main bonding jumper connection point and, for services over 1,000A on solidly grounded wye systems of more than 150V to ground, ground fault protection of equipment (GFPE) per NEC 230.95.
−
−# Main Overcurrent Device {toc}
−
−## Main Breaker vs. Main Lugs Only {toc}
−
−### The main overcurrent device configuration shall be as indicated in the datasheet.
−
−```datasheet
−label: Main Overcurrent Device Configuration
−type: radio
−drawing_ref: "panel schedule"
−options:
− - "Main circuit breaker (MCB)"
− - "Main lugs only (MLO)"
−default: deferred
−```
−
−### A main circuit breaker configuration is required when the panelboard serves as the building or tenant service disconnect, when a local means of simultaneously de-energizing all branch circuits is required for safety, and when the feeder overcurrent device is remote from the panelboard or is not readily accessible from the working space in front of the panel.
−
−### A main lug only (MLO) configuration is acceptable for panelboards that are sub-fed from a readily accessible overcurrent device that can be used as the disconnecting means, and for panelboards where NEC 408.36 permits omission of the main device.
−
−### MLO panelboards shall be fed from an overcurrent protective device sized per NEC 240.21 and protected for the bus rating of the panelboard.
−
−## Main Breaker Rating {toc}
−
−### Main breaker frame size and trip rating shall be as indicated in the datasheet.
−
−```datasheet
−label: Main Breaker Trip Rating
−type: range
−unit: A
−drawing_ref: "panel schedule"
−options:
− min: 70
− max: 1200
− setpoints: [70, 100, 125, 150, 175, 200, 225, 250, 300, 350, 400, 500, 600, 700, 800, 1000, 1200]
−default: deferred
−```
−
−### The main breaker trip rating shall not exceed the bus ampere rating of the panelboard.
−
−### Where the feeder protective device is used as the sole overcurrent protection for the panelboard bus, the feeder device shall be sized not to exceed the bus ampere rating per NEC 408.36.
−
−## Main Breaker Type {toc}
−
−### The main breaker type shall be as indicated in the datasheet.
−
−```datasheet
−label: Main Breaker Type
−type: select
−options:
− - "Thermal-magnetic (standard, fixed trip)"
− - "Electronic trip — adjustable long-time, instantaneous"
− - "Electronic trip — LSI (long-time, short-time, instantaneous)"
− - "Electronic trip — LSIG (long-time, short-time, instantaneous, ground fault)"
−default: "Thermal-magnetic (standard, fixed trip)"
−```
−
−### Thermal-magnetic breakers are appropriate for standard commercial applications up to approximately 400A. {note}
−
−### Electronic trip units with adjustable settings provide greater coordination flexibility for larger main breakers and are preferred for main breakers 400A and above where selective coordination with upstream devices is required.
−
−### LSIG trip units include integral ground fault protection of equipment (GFPE) and satisfy NEC 230.95 requirements for services over 1,000A on qualifying systems without separate GFPE relay panels. {note}
−
−## Ground Fault Protection of Equipment (GFPE) {toc}
−
−### Where GFPE is required, the means of providing it shall be as indicated in the datasheet.
−
−```datasheet
−label: Ground Fault Protection of Equipment (GFPE)
−type: select
−options:
− - "Not required — system voltage or disconnect rating below the NFPA 70 230.95 threshold"
− - "Integral to main breaker LSIG trip unit"
− - "Separate GFPE relay and sensor (UL 1053)"
−```
−
−### Whether GFPE is required at all is fixed by NFPA 70 230.95 from the system voltage and the disconnect rating; where the threshold is not reached the field records "Not required", and where it is, the means of providing it is the project selection. {note}
−
−### NFPA 70 Article 230.95 requires ground fault protection of equipment for solidly grounded wye services of more than 150V to ground (i.e., 277/480V systems) where the service disconnecting means is rated 1,000A or more.
−
−### GFPE shall operate to open all ungrounded service conductors when a ground fault current of 1,200A or more persists.
−
−### The maximum time delay before operation shall not exceed one second (60 cycles) for ground-fault currents of 3,000A or more.
−
−### GFPE shall be performance-tested after installation per NEC 230.95(C) using primary current injection.
−
−### Test procedures shall be submitted prior to testing.
−
−### GFPE is intended to protect equipment from the arcing damage caused by low-level ground faults that may not be cleared promptly by the main overcurrent device; it is not a substitute for personnel protection provided by GFCI devices on branch circuits. {note}
−
−## Arc Energy Reduction (NEC 240.87) {toc}
−
−### Where arc energy reduction is required, the method shall be as indicated in the datasheet.
−
−```datasheet
−label: Arc Energy Reduction Method (NEC 240.87)
−type: select
−options:
− - "Not applicable — main breaker rated or adjusted below 1,200A"
− - "Zone-selective interlocking (ZSI)"
− - "Energy-reducing maintenance switch with local status indicator (ERMS)"
− - "Energy-reducing active arc flash mitigation system"
− - "Permanent instantaneous trip setting"
− - "Approved equivalent method per NEC 240.87(B)(6)"
−```
−
−### NEC 240.87 requires that where a circuit breaker is rated or adjusted to 1,200A or higher, a means shall be provided to reduce the clearing time of the circuit breaker and the energy available during a line-side arcing fault.
−
−### This requirement applies to the main breaker where its trip setting is 1,200A or more.
−
−### Zone-selective interlocking is the preferred method for panelboards because it reduces arc flash incident energy during maintenance without requiring mode changes, and it does not compromise normal selective coordination. {note}
−
−### The arc energy reduction method, the required documentation per NEC 240.87(A), and the performance test per NEC 240.87(C) shall be completed and submitted as part of the project closeout.
−
−# Physical Construction {toc}
−
−## Enclosure {toc}
−
−### Enclosure shall be a dead-front, metal-enclosed assembly, listed and labeled to UL 67, with the enclosure cabinet tested per UL 50 or UL 50E as appropriate for the installation environment.
−
−### Cabinet shall be fabricated from steel with galvanized interior components.
−
−### The enclosure NEMA rating shall be as indicated in the datasheet.
−
−```datasheet
−label: Enclosure NEMA Rating
−type: select
−options:
− - "NEMA 1 — Indoor, general purpose (dry, climate-controlled)"
− - "NEMA 3R — Outdoor, rainproof (exposed or sheltered outdoor)"
− - "NEMA 4 — Watertight (indoor or outdoor, hose-directed water)"
− - "NEMA 4X — Watertight, corrosion-resistant (stainless steel or fiberglass)"
− - "NEMA 12 — Industrial dust-tight (indoor, no hose-down)"
−default: "NEMA 1 — Indoor, general purpose (dry, climate-controlled)"
−```
−
−### The mounting type shall be as indicated in the datasheet.
−
−```datasheet
−label: Mounting Type
−type: radio
−drawing_ref: "panel schedule"
−options:
− - "Surface-mounted (enclosure projects from wall)"
− - "Flush-mounted (trim flange at finished wall surface, box recessed)"
− - "Semi-flush-mounted (box partially recessed, trim overlapping the wall face)"
− - "Free-standing (floor-mounted)"
−default: deferred
−```
−
−### The enclosure finish color shall be as indicated in the datasheet.
−
−```datasheet
−label: Enclosure Finish Color
−type: text
−default: "ANSI 61 gray"
−```
−
−### Door shall be hinged with a stainless steel piano hinge and shall be equipped with a combination lock and latch.
−
−### All panelboard door locks on a single project shall be keyed alike.
−
−### The front trim shall be of the dead-front type, concealing all energized parts and all overcurrent device line terminals when the door is open.
−
−### A directory cardholder with a transparent cover shall be mounted on the inside face of the door.
−
−### Single-door enclosures shall provide full-front access to all circuit breakers and trim.
−
−### The door shall be capable of being held open at 90 degrees without support, allowing hands-free operation.
−
−### NEMA 1 is the baseline for interior commercial electrical rooms, mechanical rooms, and utility spaces that are maintained dry and climate-controlled. {note}
−
−### NEMA 3R is required for all outdoor installations — panels mounted on building exteriors, in open parking structures, or on rooftops — and protects against rain, sleet, snow, and ice formation.
−
−### Wet and wash-down locations shall use a NEMA 4 or NEMA 4X enclosure.
−
−### NEMA 4X is required in food processing facilities, car wash equipment rooms, coastal or marine environments with significant salt air exposure, and chemical process areas.
−
−### The enclosure NEMA rating shall be consistent with the installation environment shown on the electrical plans.
−
−### Flush-mounted installations require that the wall construction accommodate the full enclosure depth plus clearance for conduit entries.
−
−### Coordinate with architectural drawings for wall type, thickness, and finished surface location.
−
−### Free-standing floor-mounted panelboards (typically 800A and above) shall be mounted on housekeeping pads per the Installation section.
−
−### Outdoor and wet location enclosures shall receive an enhanced coating system.
−
−### Where stainless steel enclosures are provided (NEMA 4X stainless), painted finish is not required on the enclosure exterior; interior surfaces may receive a corrosion-inhibiting coating.
−
−## Bus Assembly {toc}
−
−### The bus assembly shall be the panelboard manufacturer's standard design, factory-assembled and tested.
−
−### Main bus, branch circuit bus, and neutral bus shall be rated for the current, voltage, and fault current specified.
−
−### The main and branch bus material shall be as indicated in the datasheet.
−
−```datasheet
−label: Main and Branch Bus Material
−type: radio
−options:
− - "Copper"
− - "Aluminum (tin-plated)"
−```
−
−### The neutral bus rating shall be as indicated in the datasheet.
−
−```datasheet
−label: Neutral Bus Rating
−type: select
−options:
− - "Not applicable (ungrounded or 2-wire system, no neutral)"
− - "100% of phase bus rating"
− - "50% of phase bus rating (reduced)"
− - "200% of phase bus rating (oversized for harmonic loads)"
−default: "100% of phase bus rating"
−```
−
−### The ground bus shall be as indicated in the datasheet.
−
−```datasheet
−label: Ground Bus
−type: radio
−options:
− - "Included — copper, sized per NEC 250"
− - "Included — copper, plus a separate isolated (insulated) ground bus for sensitive-equipment branch circuits"
− - "Not included (bonding via raceway or other listed means)"
−default: "Included — copper, sized per NEC 250"
−```
−
−### Copper bus provides higher conductivity per unit cross-section and lower contact resistance at bolted joints, and is the preferred selection for higher-ampere-rated panelboards and service entrance equipment. {note}
−
−### Aluminum bus is acceptable for standard commercial branch-circuit panelboards and offers weight savings in large assemblies; aluminum bus shall be tin-plated at all joint surfaces to prevent oxidation.
−
−### Bare aluminum bus is not acceptable.
−
−### Bus connections to copper terminals or other dissimilar metals shall use listed connectors rated for aluminum-to-copper connections.
−
−### A 100% neutral bus is appropriate for most commercial applications with a balanced mix of linear and nonlinear loads. {note}
−
−### A 50% neutral bus may be used only where the engineer has determined through harmonic analysis per IEEE 519 that third-harmonic and triplen-harmonic loading is minimal.
−
−### Where nonlinear single-phase loads (variable frequency drives, switching power supplies, LED drivers, data center UPS) represent a significant portion of the panel load, an oversized neutral bus rated 200% of the phase bus is required to carry the additive triplen harmonic currents that flow in the neutral without overheating.
−
−### A dedicated ground bus shall be included in all panelboards used as service entrance equipment and in all panelboards where equipment grounding conductors are present in the feeder or branch circuits.
−
−### The ground bus shall be insulated from the enclosure and neutral bus in all panelboards other than the service entrance panel where the main bonding jumper is located.
−
−### At the service entrance panel, the ground bus shall be bonded to the neutral bus and enclosure per NEC 250.
−
−### An isolated (insulated) equipment grounding bus shall be furnished only where isolated-ground branch circuits serving sensitive equipment are indicated.
−
−### An isolated ground bus is mounted on insulating standoffs so that the isolated grounding conductors return to the derived-system bonding point without picking up the enclosure's noise currents; furnishing one where no isolated-ground circuits exist adds cost and invites incorrect field terminations. {note}
−
−## Interior and Wiring Compartment {toc}
−
−### The number of branch circuit spaces (poles) shall be as indicated in the datasheet.
−
−```datasheet
−label: Number of Branch Circuit Spaces
−type: range
−unit: poles
−drawing_ref: "panel schedule"
−options:
− min: 12
− max: 84
− setpoints: [12, 18, 20, 24, 30, 36, 42, 48, 54, 60, 72, 84]
−default: deferred
−```
−
−### The space reserved for future circuits shall be as indicated in the datasheet.
−
−```datasheet
−label: Space Reservation for Future Circuits
−type: select
−options:
− - "No spare spaces (all spaces populated)"
− - "2 spare single-pole spaces"
− - "4 spare single-pole spaces (10% spare minimum)"
− - "5% spare spaces"
− - "10% spare spaces"
− - "15% spare spaces"
− - "20% spare spaces"
− - "25% spare spaces"
− - "30% spare spaces"
−default: "4 spare single-pole spaces (10% spare minimum)"
−```
−
−### The interior shall provide separate wiring compartments so that supply conductors and branch circuit conductors do not occupy the same space as the bus assembly.
−
−### Wiring gutter spaces shall comply with NEC 312.6 for the conductor sizes and quantities being served.
−
−### Interior shall be arranged so that conductors can be installed and maintained without disturbing adjacent circuits.
−
−### Branch circuit breakers shall be arranged in a vertical column or two-column configuration.
−
−### Providing a minimum of 10% spare circuit spaces is recommended for all commercial projects to accommodate future tenant modifications without replacing the panelboard. {note}
−
−### Spaces designated as spare shall have blank filler plates installed in the trim and fully equipped bus stabs available for future breaker installation without internal modification.
−
−## Conduit Entry Areas {toc}
−
−### The primary conduit entry direction shall be as indicated in the datasheet.
−
−```datasheet
−label: Primary Conduit Entry Direction
−type: radio
−drawing_ref: "electrical plans"
−options:
− - "Top entry (conduit enters from above)"
− - "Bottom entry (conduit enters from below)"
− - "Top and bottom (supply from top, branch circuits from bottom)"
−default: deferred
−```
−
−### Conduit entry areas shall be provided at top, bottom, and where required by the installation configuration, at sides.
−
−### Knockouts or concentric rings shall be provided at standard conduit trade sizes.
−
−### Where conduit enters from the top of a panelboard in a wet location, conduit entries shall be protected with conduit hubs listed for wet locations to prevent water infiltration.
−
−### Flush-mounted panelboards shall be furnished with the number of empty conduit stub-outs indicated in the datasheet, run from the panelboard gutter to an accessible location above an accessible ceiling and capped.
−
−```datasheet
−label: Flush-Mount Spare Conduit Stub-Outs
−type: range
−unit: count
−options:
− min: 0
− max: 8
− step: 1
−```
−
−### Once the wall is closed, a flush-mounted panelboard cannot accept a new circuit without demolishing finish work; stub-outs left at rough-in are the only economical path for future circuit extension, and the quantity is a judgment about how much future flexibility the Owner is buying. {note}
−
−# Overcurrent Protective Devices {toc}
−
−## Branch Circuit Breaker Type {toc}
−
−### All branch circuit breakers shall comply with UL 489.
−
−### Breakers shall be thermal-magnetic or electronic trip, rated for the voltage and frequency of the system.
−
−### The branch circuit breaker mounting type shall be as indicated in the datasheet.
−
−```datasheet
−label: Branch Circuit Breaker Mounting Type
−type: radio
−options:
− - "Bolt-on (mechanically secured to bus)"
− - "Plug-on / plug-in (spring-clip engagement)"
− - "Plug-on neutral capable (plug-on with integral neutral connection)"
−default: "Plug-on / plug-in (spring-clip engagement)"
−```
−
−### The pole counts the interior shall accommodate are as indicated in the datasheet.
−
−```datasheet
−label: Branch Circuit Breaker Poles
−type: checkbox
−options:
− - "1-pole (120V, 15A–30A branch circuits)"
− - "2-pole (240V or 2-phase 208V branch circuits)"
− - "3-pole (3-phase branch circuits)"
−default:
− - "1-pole (120V, 15A–30A branch circuits)"
− - "2-pole (240V or 2-phase 208V branch circuits)"
−```
−
−### Individual breaker frame sizes and trip ratings shall be as indicated in the datasheet.
−
−```datasheet
−label: Branch Circuit Breaker Trip Ratings
−type: text
−drawing_ref: "panel schedule"
−default: deferred
−```
−
−### Breakers shall be the panelboard manufacturer's listed breakers for the specific panelboard model to ensure proper engagement with the bus stabs and compliance with the assembly SCCR.
−
−### Bolt-on breakers provide a more positive mechanical and electrical connection to the bus and are the standard for industrial and higher-vibration environments and for power distribution panelboards. {note}
−
−### Plug-on breakers are the standard for commercial lighting and branch-circuit panelboards and offer faster installation and removal. {note}
−
−### Plug-on neutral (PON) capable interiors eliminate the need for a separate neutral pigtail from a GFCI or AFCI breaker to the neutral bus; the PON breaker connects directly to a neutral bus rail integral to the interior. {note}
−
−### Tandem (twin) breakers shall be installed only in panelboard positions specifically listed to accept them, and only where the resulting overcurrent device count does not exceed the number for which the panelboard is designed, rated, and listed per NEC 408.54.
−
−### A tandem breaker doubles the circuits in one space but does not raise the panelboard's listed device count; installing tandems in unlisted positions to squeeze in circuits is a common field expedient that fails inspection. {note}
−
−### All unassigned (spare) circuit spaces shall be equipped with listed filler plates; they shall not be left open.
−
−## AFCI and GFCI Protection {toc}
−
−### Arc-Fault Circuit-Interrupter (AFCI) Protection {toc}
−
−#### The extent of AFCI branch circuit protection shall be as indicated in the datasheet.
−
−```datasheet
−label: AFCI Branch Circuit Breakers
−type: radio
−drawing_ref: "panel schedule"
−options:
− - "Required at all 120V 15A and 20A branch circuits in this panel"
− - "Required at designated branch circuits"
− - "Not required"
−default: deferred
−```
−
−#### NFPA 70 Section 210.12 requires combination-type AFCI protection on all 120V, single-phase, 15A and 20A branch circuits supplying outlets and devices in dwelling units, dormitories, hotel and motel guest rooms, and similar residential occupancies.
−
−#### AFCI protection shall be provided by a listed combination-type AFCI circuit breaker installed at the panelboard origin of the branch circuit, or by listed outlet branch circuit AFCI protection at the first outlet in combination with a listed branch/feeder AFCI at the origin.
−
−#### AFCI breakers detect both series arcing (damaged conductors) and parallel arcing (line-to-ground or line-to-neutral arcing faults) that would not be cleared by a standard thermal-magnetic breaker. {note}
−
−#### For commercial occupancies where AFCI is not code-required, the Engineer may specify AFCI breakers in locations serving areas with high concentrations of plug loads or extension cords (open office areas, hotel convention areas) as a proactive fire prevention measure.
−
−### Ground-Fault Circuit-Interrupter (GFCI) Protection {toc}
−
−#### The means of providing GFCI protection shall be as indicated in the datasheet.
−
−```datasheet
−label: GFCI Branch Circuit Breakers (at panelboard)
−type: radio
−options:
− - "Provided at panelboard for all circuits requiring GFCI (GFCI breaker per circuit)"
− - "GFCI provided at point of use (GFCI receptacle or device, not at panelboard)"
− - "Combination AFCI/GFCI breakers at panelboard (dual-function)"
−drawing_ref: "panel schedule"
−default: deferred
−```
−
−#### NFPA 70 Section 210.8 requires GFCI protection for personnel on all 125V through 250V receptacles supplied by single-phase branch circuits rated 150V or less to ground, in a broad range of locations including bathrooms, kitchens, garages, outdoors, unfinished basements, crawl spaces, boathouses, rooftops, and commercial kitchen areas.
−
−#### GFCI protection shall be provided by a listed GFCI circuit breaker at the panelboard or by a listed GFCI receptacle at the first outlet.
−
−#### GFCI breakers at the panelboard protect the entire branch circuit wiring as well as the connected devices and are preferred where the wiring method or installation environment creates a risk of insulation damage in the circuit conductors. {note}
−
−#### GFCI protection at the panelboard is also more accessible for reset following a trip. {note}
−
−#### Dual-function AFCI/GFCI combination breakers satisfy both requirements on a single pole and are particularly efficient in residential-type panelboards where many circuits require both types of protection. {note}
−
−## Series Rating {toc}
−
−### Series rating is permitted per NEC 240.86 where the combination of an upstream overcurrent device and a downstream branch circuit breaker has been tested as a series-rated combination by a testing laboratory.
−
−### Series rating allows lower-rated (and lower-cost) branch circuit breakers to be used downstream of a higher-rated main or feeder breaker in locations where the actual available fault current at the panel is less than the individual breaker interrupt rating would require. {note}
−
−### Series rating shall not be used at service entrance panels or at the first downstream distribution point after the utility service entrance, where fault current levels are highest.
−
−### Where series rating is applied, the panelboard shall be permanently and legibly marked with a warning label per NEC 110.22 identifying it as a series combination system and identifying the required replacement components.
−
−### Replacement of any overcurrent device in a series-rated assembly shall use only the same manufacturer, type, and rating as originally specified and listed in the tested combination.
−
−### Substitutions that appear equivalent but are not part of the tested combination break the series rating and render the assembly non-code-compliant. {note}
−
−## Selective Coordination {toc}
−
−### Selective coordination requires that only the overcurrent device immediately upstream of a fault opens, leaving every device further upstream closed so that unfaulted portions of the system stay energized. {note}
−
−### Selective coordination is mandated by NFPA 70 Articles 700, 701, and 708 for emergency, legally required standby, and critical operations power systems, where a cascading trip would extinguish egress lighting or drop life-safety loads. {note}
−
−### Where the panelboard serves an emergency, legally required standby, or critical operations power system, its overcurrent devices shall be selectively coordinated with all upstream and downstream overcurrent devices.
−
−### Selective coordination shall be demonstrated by a study that overlays the published time-current characteristic curves of the actual specified devices, including the instantaneous region.
−
−### Coordination cannot be inferred from ampere ratings alone; two devices two frame sizes apart may still overlap in the instantaneous region, which is where the vast majority of coordination failures occur. {note}
−
−### Series-rated combinations shall not be applied where selective coordination is required, because a series combination relies on both devices opening for a high-magnitude fault.
−
−# Surge Protective Devices {toc}
−
−## SPD Requirements {toc}
−
−### Whether a surge protective device is provided at the panelboard shall be as indicated in the datasheet.
−
−```datasheet
−label: Surge Protective Device (SPD)
−type: radio
−options:
− - "Provided"
− - "Not provided"
−default: "Provided"
−```
−
−### The SPD type shall be as indicated in the datasheet.
−
−```datasheet
−label: SPD Type
−type: radio
−options:
− - "Type 1 — permanently connected on the line side of the main disconnect"
− - "Type 2 — permanently connected on the load side of the main disconnect"
− - "Type 1+2 combination (line-side and load-side protection in one assembly)"
−default: "Type 2 — permanently connected on the load side of the main disconnect"
−```
−
−### The SPD mounting configuration shall be as indicated in the datasheet.
−
−```datasheet
−label: SPD Configuration
−type: radio
−options:
− - "Factory-installed, integral to the panelboard"
− - "Field-installed in a dedicated space within the panel"
− - "External, mounted adjacent to the panel"
−default: "Factory-installed, integral to the panelboard"
−```
−
−### The SPD nominal discharge current rating shall be as indicated in the datasheet.
−
−```datasheet
−label: SPD Nominal Discharge Current Rating
−type: range
−unit: kA
−options:
− min: 10
− max: 80
− setpoints: [10, 20, 40, 80]
−default: 20
−```
−
−### Nominal discharge current ratings correspond to exposure: 10 kA suits standard commercial occupancies, 20 kA provides enhanced protection, 40 kA suits critical facilities such as data centers, and 80 kA suits high-exposure locations such as rooftop panels. {note}
−
−### NFPA 70 Section 230.67 requires a surge protective device (SPD) on all services supplying dwelling units, and Section 215.18 extends this requirement to feeder panelboards supplying the same occupancy types.
−
−### SPDs protect connected equipment from transient overvoltages caused by utility switching, lightning-induced surges on the distribution system, and load-switching transients within the building. {note}
−
−### SPDs are strongly recommended for all commercial panelboards serving sensitive electronic equipment (IT equipment, building automation controls, variable frequency drives, medical equipment, laboratory instrumentation). {note}
−
−### Transient surge damage is cumulative; even surges that do not cause immediate failure degrade insulation and reduce equipment lifespan. {note}
−
−### Type 1 SPDs are listed to be installed ahead of the service disconnecting means and may be connected without an overcurrent device.
−
−### Type 2 SPDs are the standard for panelboards downstream of the service entrance and shall be connected per the manufacturer's instructions with an integral or external overcurrent protective device.
−
−### Only one of the two types is typically required at any given panel location; coordinate the placement of SPDs across the distribution system to avoid redundant or conflicting installations.
−
−### SPDs shall comply with UL 1449 (4th edition or current) and shall be listed for the system voltage and configuration.
−
−### The SPD shall include a status indicator (visible LED) showing device health, and shall include audible or dry-contact alarm output for remote monitoring where continuous operation is critical.
−
−### SPDs shall be connected as close as practicable to the bus, using the shortest possible lead lengths, to minimize the series inductance that reduces surge clamping effectiveness.
−
−# Metering and Monitoring {toc}
−
−## Metering at the panelboard shall be as indicated in the datasheet.
−
−```datasheet
−label: Metering at Panelboard
−type: select
−options:
− - "No metering"
− - "Metering provisions only (current transformer compartment; meter furnished separately)"
− - "Current-only monitoring (per-phase ammeter)"
− - "Multifunction digital panel meter (V, A, kW, kWh)"
− - "Revenue-grade energy meter (ANSI C12.1 Class 0.5)"
−default: "No metering"
−```
−
−## Where a meter is provided, its communication protocol shall be as indicated in the datasheet.
−
−```datasheet
−label: Meter Communication Protocol
−type: select
−options:
− - "Not applicable — no meter provided"
− - "Modbus RTU (RS-485)"
− - "Modbus TCP/IP (Ethernet)"
− - "BACnet MS/TP"
− - "BACnet IP"
−```
−
−## Where submetering is required by the adopted energy code (ASHRAE 90.1 Section 8.4.3 or applicable state energy code), a meter capable of recording energy consumption (kWh) over time shall be provided with a communication interface for integration with the building management system or energy management platform.
−
−## Revenue-grade metering is required where energy data is used for tenant billing or utility interconnection purposes.
−
−# Identification and Circuit Directory {toc}
−
−## Circuit Directory {toc}
−
−### The circuit directory format shall be as indicated in the datasheet.
−
−```datasheet
−label: Circuit Directory Format
−type: radio
−options:
− - "Typed and laminated (provided and installed by Contractor at closeout)"
− - "Computer-printed insert (provided in manufacturer's directory holder)"
− - "Machine-engraved on aluminum insert"
−default: "Typed and laminated (provided and installed by Contractor at closeout)"
−```
−
−### Every panelboard shall have a circuit directory affixed to the inside of the door per NEC 408.4.
−
−### The circuit directory shall identify every circuit and every spare position by a clear, specific description of the load served.
−
−### Identification shall include the space or area served and the load type (e.g., "Suite 204 — Receptacles East Wall" or "AHU-3 — Compressor").
−
−### Generic descriptions such as "Spare," "Lights," or "Power" without specifying the area or load type do not comply with NEC 408.4 and are not acceptable.
−
−### Circuit directories shall be completed and installed prior to the final inspection.
−
−### The Contractor shall provide an updated circuit directory reflecting all as-installed circuit assignments as part of the record document submittals.
−
−### Handwritten circuit directories are not acceptable.
−
−### Where symbols or abbreviations are used to shorten circuit descriptions per NEC 408.4(A), a legend defining all symbols and abbreviations shall be included in the circuit directory.
−
−## Panel Nameplate {toc}
−
−### Manufacturer shall provide an engraved or machine-printed nameplate on the outside of the enclosure identifying:
−
−- Panel designation (matching the contract drawings and panel schedule)
−- System voltage and number of phases and wires
−- Bus ampere rating
−- Short-circuit current rating (SCCR/AIC)
−- Manufacturer name and catalog or order number
−- Date of manufacture
−
−### Each panelboard used as service equipment shall be field-marked with the maximum available fault current at its line terminals and the date the calculation was performed, per NEC 110.24, and the marking shall be updated whenever the supply is modified.
−
−### The panel nameplate material shall be as indicated in the datasheet.
−
−```datasheet
−label: Panel Nameplate Material
−type: radio
−options:
− - "Laminated phenolic (indoor)"
− - "Stainless steel (outdoor or corrosive environment)"
− - "Aluminum (anodized)"
−default: "Laminated phenolic (indoor)"
−```
−
−## Arc Flash Warning Label {toc}
−
−### Each panelboard shall receive an arc flash warning label per NFPA 70E and IEEE 1584, installed prior to energization.
−
−### The basis of the arc flash label shall be as indicated in the datasheet.
−
−```datasheet
−label: Arc Flash Analysis
−type: radio
−options:
− - "Formal arc flash analysis (IEEE 1584) — label with incident energy and boundary"
− - "Generic warning label — no formal analysis performed"
−```
−
−### Where a formal arc flash hazard analysis has been performed for the project, labels shall include the incident energy in cal/cm², the arc flash boundary distance, the required personal protective equipment (PPE) category, and the date of the study.
−
−### Where no formal arc flash analysis has been performed, a generic warning label identifying the voltage class and requiring use of appropriate PPE shall be installed as a minimum.
−
−### A formal arc flash analysis is recommended for all panelboards 400A and above and for any panel in an occupied area where maintenance personnel will be present with the panel energized. {note}
−
−### The analysis enables selection of appropriate PPE, supports documentation of safe work procedures, and is increasingly required by insurance carriers and OSHA enforcement. {note}
−
−# Testing {toc}
−
−## Factory Tests {toc}
−
−### Panelboard assemblies shall be factory-tested per NEMA PB 1 and UL 67 production test requirements prior to shipment.
−### Factory tests shall include:
−
−- Dielectric withstand test on the bus assembly (hi-pot) per UL 67 requirements
−- Mechanical operation of all circuit breakers — each breaker shall be operated through at least one open/close cycle to verify free operation and proper engagement with the bus stabs
−- Bus assembly inspection — verify all bus joints are properly torqued, bus is fully insulated, and no loose components or foreign objects are present
−- Dimensional and visual inspection against the approved shop drawings
−
−### Each factory-installed surge protective device shall be functionally tested at the factory and its test record furnished before shipment.
−
−### The extent of factory acceptance testing shall be as indicated in the datasheet.
−
−```datasheet
−label: Factory Acceptance Testing
−type: radio
−options:
− - "Standard production tests (unwitnessed, with certified test report)"
− - "Witnessed factory test (owner or engineer representative present)"
− - "Not required beyond standard UL 67 production tests"
−default: "Standard production tests (unwitnessed, with certified test report)"
−```
−
−### Witnessed factory testing is recommended for switchboard-height panelboards 800A and above, for service entrance equipment, and for projects where the lead time for repairs after a field failure is unacceptable. {note}
−
−### The manufacturer shall provide a minimum of two weeks' advance notice of test readiness and shall submit test procedures for review before testing.
−
−## Field Acceptance Tests {toc}
−
−### NETA ATS acceptance testing for panelboards shall include as a minimum:
−
−- Visual and mechanical inspection of the enclosure, bus assembly, breaker engagement, nameplate data, wiring connections, and clearances
−- Insulation resistance test on each phase bus, neutral bus, and each individual branch circuit (phase-to-phase and phase-to-ground, minimum 1 minute at 500VDC for systems below 300V and 1,000VDC for systems 300V through 1000V)
−- Contact resistance measurement on main bus joints and supply conductor terminations (microohmmeter)
−- Operational test of each circuit breaker — mechanical and electrical (trip coil, if provided)
−- Functional test of GFPE relay system per NEC 230.95(C) by primary current injection (where GFPE is installed)
−- Verification of neutral-to-ground separation in all non-service-entrance panels
−- Verification that all unused circuit spaces have filler plates and that bus stabs are not exposed
−- Circuit continuity check on each installed branch circuit
−- Verification of arc flash labels and circuit directory completeness
−- Torque verification of each accessible bolted bus joint and terminal lug against the manufacturer's published value, with the applied values recorded
−
−```datasheet
−label: Field Acceptance Tests Required
−type: checkbox
−options:
− - "Visual and mechanical inspection"
− - "Insulation resistance test"
− - "Contact resistance measurement (microohmmeter)"
− - "Torque verification with recorded values"
− - "Operational test of each circuit breaker"
− - "GFPE functional test by primary current injection"
− - "Neutral-to-ground separation verification"
− - "Filler plate and exposed bus stab verification"
− - "Branch circuit continuity check"
− - "Arc flash label and circuit directory verification"
−default:
− - "Visual and mechanical inspection"
− - "Insulation resistance test"
− - "Contact resistance measurement (microohmmeter)"
− - "Torque verification with recorded values"
− - "Operational test of each circuit breaker"
− - "Neutral-to-ground separation verification"
− - "Filler plate and exposed bus stab verification"
− - "Branch circuit continuity check"
− - "Arc flash label and circuit directory verification"
−```
−
−### Contractor shall engage a qualified independent testing firm to perform acceptance testing per NETA ATS after installation is complete and before the panelboard is energized under load.
−
−### The testing firm shall be regularly engaged in testing electrical power equipment, employing NETA-certified technicians.
−
−### Ground resistance and bonding continuity testing shall be performed per [[sync/grounding-and-bonding]].
−
−## Performance Test — GFPE {toc}
−
−### Where ground fault protection of equipment is installed per NEC 230.95, the Contractor shall arrange for a performance test of the GFPE system upon completion of the installation and before the service is energized for normal operation.
−
−### The test shall be conducted by a qualified person using primary current injection equipment per the GFPE manufacturer's test instructions.
−
−### Test results, including the actual pickup current and time-delay values, shall be recorded and submitted as part of project closeout.
−
−# Installation {toc}
−
−## Working Clearances {toc}
−
−| Nominal Voltage | Condition 1 (exposed on one side) | Condition 2 (exposed on both sides) | Condition 3 (exposed on both sides, energized equipment opposite) |
−|-----------------|-----------------------------------|--------------------------------------|-------------------------------------------------------------------|
−| 0–150V | 36 in. | 36 in. | 36 in. |
−| 151–1000V | 36 in. | 42 in. | 48 in. |
−
−### Minimum working space shall be maintained in front of panelboards per NFPA 70 Article 110.26.
−
−### The applicable working clearance condition shall be as indicated in the datasheet.
−
−```datasheet
−label: Working Clearance Condition
−type: select
−drawing_ref: "electrical plans"
−options:
− - "Condition 1 — exposed energized parts on one side of the working space"
− - "Condition 2 — exposed energized parts on both sides"
− - "Condition 3 — energized equipment on the opposite side of the working space"
−default: deferred
−```
−
−### Working space depth shall be measured from the front of the live parts or the front of the enclosure, whichever is greater, to any obstruction.
−
−### Working space shall not be used for storage.
−
−### Dedicated electrical space above the panelboard to the structural ceiling (or 6 ft above the top of the panel, whichever is lower) shall be maintained per NEC 110.26(E).
−
−### This dedicated space shall not be penetrated by piping, ducts, or other non-electrical systems unless protected from drips or leaks.
−
−### Headroom in working spaces shall be a minimum of 6.5 ft or the height of the equipment, whichever is greater.
−
−## Mounting {toc}
−
−### The mounting height to the top of the panel shall be as indicated in the datasheet.
−
−```datasheet
−label: Mounting Height (to top of panel)
−type: range
−unit: in
−options:
− min: 48
− max: 78
− step: 2
−default: 72
−```
−
−### Panelboards shall be mounted plumb, level, and secure per manufacturer's installation instructions and NEMA PB 1.1.
−
−### Surface-mounted panelboards shall be anchored to the structural wall with minimum four fasteners engaging studs, masonry anchors, or structural backing.
−
−### Flush-mounted panelboards shall be secured to the rough opening framing or structural backing.
−
−### Where multiple panelboards are mounted in a row, the top of each panel shall be at a consistent height unless the installation conditions require otherwise.
−
−### The maximum height above the finished floor or working platform to the center of the grip of the highest operating handle shall be as indicated in the datasheet.
−
−```datasheet
−label: Maximum Operating Handle Height Above Finished Floor
−type: range
−unit: in
−options:
− min: 48
− max: 79
− step: 1
−default: 79
−```
−
−### No overcurrent device operating handle shall be installed so that the center of its grip is more than 6 ft 7 in. (2.0 m) above the floor or working platform, per NEC 240.24(A).
−
−### The 6 ft 7 in. limit is a reach requirement, not a mounting convention: a tall panel set to a comfortable top-of-panel height can still push its uppermost handle past the limit, which is why the handle height is verified separately from the mounting height. {note}
−
−### Panelboards shall not be mounted in bathrooms, clothes closets, or above steps of a stairway per NEC 240.24(E) and (F).
−
−## Housekeeping Pads {toc}
−
−### Free-standing floor-mounted panelboards (typically 800A and above) shall be mounted on reinforced concrete housekeeping pads extending a minimum of 3 in. beyond the base of the enclosure on all sides.
−
−### Pads shall be a minimum of 3.5 in. above the finished floor for indoor installations and 4 in. above finished grade for outdoor installations to protect against water pooling and forklift damage.
−
−### Coordinate pad dimensions, anchor bolt locations, and conduit penetration locations with the panelboard shop drawings prior to concrete placement.
−
−### See [[sync/cast-in-place-concrete]] for housekeeping pad construction requirements.
−
−## Conduit Terminations and Conductor Connections {toc}
−
−### The main lug termination type shall be as indicated in the datasheet.
−
−```datasheet
−label: Main Lug Termination Type
−type: radio
−options:
− - "Mechanical set-screw lugs (standard)"
− - "Compression (crimp) lugs (field-installed)"
− - "Bus bar extension lugs (large conductors, parallel sets)"
−default: "Mechanical set-screw lugs (standard)"
−```
−
−### Conduit entries shall comply with [[sync/raceways-and-conduit]].
−
−### All conduit penetrations into the panelboard enclosure shall be sealed where required by the installation conditions (wet locations, firestopping, rodent exclusion).
−
−### Conduit hubs listed for wet locations shall be used at all wet location panels.
−
−### Conductors shall comply with [[sync/conductors-and-cables]] and shall be installed per the conductor manufacturer's minimum bend radius requirements.
−
−### Supply conductors shall be terminated in the designated line-side terminal lugs and shall not share the terminal with other conductors unless the terminal is specifically listed for multiple conductors.
−
−### All conductor terminations shall be torqued to the manufacturer's published torque specifications using a calibrated torque wrench.
−
−### Torque values shall be recorded as part of the field test documentation.
−
−### Aluminum conductors shall use conductors listed for use with the terminal material; aluminum conductors shall be prepared with listed anti-oxidant compound prior to termination unless the terminal manufacturer's instructions indicate that preparation is not required.
−
−## Conductor Organization {toc}
−
−### Within the panelboard wiring compartment, conductors shall be neatly routed, supported, and organized so that each circuit can be individually identified and accessed without disturbing adjacent circuits.
−
−### Wire ties shall be used to bundle groups of conductors.
−
−### Conductors shall not cross energized bus.
−
−## Circuit Balancing {toc}
−
−### Branch circuits shall be assigned across the phases so that, at the connected load used for the panel schedule, the load on any phase does not deviate from the average phase load by more than the tolerance indicated in the datasheet.
−
−```datasheet
−label: Maximum Phase Load Imbalance
−type: range
−unit: '%'
−options:
− min: 5
− max: 20
− step: 5
−default: 10
−```
−
−### Where the indicated tolerance cannot be met because of the fixed characteristics of the connected equipment, the Engineer of Record shall determine the acceptable phase assignment.
−
−### An unbalanced panel drives neutral current, unequal voltage drop between phases, and premature transformer and conductor heating; balancing costs nothing at the panel-schedule stage and is expensive to correct after circuits are pulled. {note}
−
−### The final phase assignment of every branch circuit shall be recorded on the record panel schedule.
−
−## Outdoor Installation Requirements {toc}
−
−### Outdoor panelboards in NEMA 3R, 4, or 4X enclosures shall be installed with:
−
−- Conduit entries sealed at the enclosure with listed conduit hubs or fittings for wet locations, with all unused knockouts sealed
−- Conduit runs entering from the bottom of the enclosure where possible; conduit runs entering from the top shall have drip loops or conduit seals to prevent water migration
−- A rain-tight conduit hub or sealing fitting where conduit enters from top
−- All sealing requirements of [[sync/raceways-and-conduit]] for wet location conduit runs
−
−### A sun shield and rain hood shall be provided as indicated in the datasheet.
−
−```datasheet
−label: Outdoor Panel Sun Shield / Weather Hood
−type: radio
−options:
− - "Required"
− - "Not required"
−default: "Not required"
−```
−
−### A sun shield and rain hood shall be provided on any outdoor panelboard in unshaded, full-sun exposure, where solar gain would drive the interior above the equipment's rated ambient.
−
−## Delivery, Storage, and Handling {toc}
−
−### Panelboards shall be delivered to the site in the manufacturer's original packaging, with all breakers, interior components, and trim protected from damage.
−
−### Equipment shall be inspected for damage upon delivery and any damage documented and reported to the manufacturer before installation.
−
−### Equipment shall be stored indoors in a clean, dry, climate-controlled location where possible.
−
−### Where indoor storage is not available, equipment shall be stored under cover on pallets, off the ground, and protected from moisture and construction debris.
−
−### Condensation heaters shall be connected and energized during storage in unheated environments if the ambient temperature may fall below the dew point, to prevent condensation on bus and insulators.
−
−# Warranty {toc}
−
−## The manufacturer shall warrant each panelboard for the period indicated in the datasheet.
−
−```datasheet
−label: Warranty Period
−type: select
−options:
− - "1 year from date of substantial completion"
− - "2 years from date of substantial completion"
− - "3 years from date of substantial completion"
− - "5 years from date of substantial completion"
−default: "1 year from date of substantial completion"
−```
−
−## The warranty coverage scope shall be as indicated in the datasheet.
−
−```datasheet
−label: Warranty Coverage Scope
−type: radio
−options:
− - "Parts only"
− - "Parts and labor"
−default: "Parts only"
−```
−
−## Additional warranty services shall be provided as indicated in the datasheet.
−
−```datasheet
−label: Additional Warranty Services
−type: checkbox
−options:
− - "Emergency response (business hours)"
− - "Emergency response (24/7)"
− - "Annual preventive maintenance included"
−```
−
−## Warranty shall cover defects in materials and workmanship under normal conditions of use.
−
−## Warranty period shall begin at the date of substantial completion, not the date of shipment or installation.
−
−## The manufacturer shall maintain the capability to provide replacement parts for the panelboard assembly for a minimum of 10 years from the date of manufacture.
−
−# Spare Parts and Maintenance {toc}
−
−## Spare circuit breakers shall be furnished as indicated in the datasheet.
−
−```datasheet
−label: Spare Circuit Breakers
−type: radio
−options:
− - "None"
− - "Two spare of each pole count and trip rating installed"
− - "10% of each circuit breaker type (minimum two)"
−default: "Two spare of each pole count and trip rating installed"
−```
−
−## Spare breakers shall be identical in manufacturer, type, pole count, frame size, and trip rating to the installed breakers.
−
−## Spare breakers shall be stored in a labeled enclosure or storage box in the electrical room, not inside the operating panel.
−
−## Additional Closeout Items {toc}
−
−### The Contractor shall provide the following additional items at substantial completion:
−
−- All blank filler plates for unused circuit positions (in addition to those installed in the panel)
−- One complete set of keys for all panelboard locks and padlocks
−- Printed or electronic copy of the panelboard manufacturer's installation, operation, and maintenance instructions
−
−## Ongoing Maintenance {toc}
−
−### Ongoing maintenance of installed panelboards shall be conducted per NEMA PB 1.1, which specifies inspection and torque re-check intervals.
−
−### Bus joint bolts shall be re-torqued at the first annual maintenance interval following energization, as thermal cycling during the first year of service may cause relaxation in bolted joints.
+---
+title: Panelboards
+category: Electrical
+description: >
+ When to use: Dead-front panelboards rated 1000 V and below, listed to UL 67 and built to NEMA PB 1, that subdivide a feeder or a service into branch circuits and feeders and hold the overcurrent device for each, whether installed as service equipment or downstream of switchgear, switchboards, transformers, or other panelboards. Covers the ratings, the interrupting rating basis, the main device, the bus, the cabinet and front, the branch circuit devices and their accessories, the surge protection and metering provisions built into the cabinet, identification, factory and field testing, installation, warranty, and spares, for single-phase and three-phase AC systems in indoor and outdoor locations.
+
+ Not intended for: Dead-front switchboards and metal-enclosed switchgear ([[sync/low-voltage-switchboards]], [[sync/low-voltage-switchgear]]); motor control centers ([[sync/motor-control-centers]]); individually enclosed switches and circuit breakers used as disconnects ([[sync/enclosed-switches-and-disconnects]]); equipment above 1000 V ([[sync/medium-voltage-switchgear]]); DC panelboards; panelboards in hazardous classified locations; the surge protective devices themselves ([[sync/surge-protective-devices]]); the meters themselves ([[sync/electrical-power-monitoring]]); the remotely operated breakers and controllers of a lighting-control panelboard ([[sync/lighting-controls]]); and the short-circuit, coordination, and arc-flash studies that establish the ratings the panelboard is ordered to ([[sync/short-circuit-study]], [[sync/protective-coordination-study]], [[sync/arc-flash-study]]).
+---
+
+# Scope {toc}
+
+## This standard governs the panelboard as a listed assembly: the bus and its supports, the main device where one is furnished, the branch circuit devices and their mounting, the cabinet and its front, the provisions built into the cabinet for surge protection and metering, and the field work that puts the panelboard into service. {note}
+
+## A panelboard is a single panel or a group of panel units assembled as one panel, installed in a cabinet and accessible only from the front, that carries buses and overcurrent devices for the control of light, heat, or power circuits; dead-front construction leaves no energized part exposed on the operating face once the front is installed. {note}
+
+## The panelboard is the last piece of distribution equipment ahead of the branch circuits, so most projects have many of them, and the values that differ from one panelboard to the next, such as the voltage, the bus rating, the main device, the number of circuits, and the breakers installed, live on the panel schedules; the datasheet of this standard carries the policy that applies to every panelboard on the project unless a schedule states otherwise. {note}
+
+## The terms "lighting and appliance branch-circuit panelboard" and "power panelboard", together with the limit of 42 overcurrent devices in one cabinet, were removed from NFPA 70 Article 408 in the 2008 edition; they still appear in older documents and in catalogs, but they carry no code consequence and are not a basis for any requirement in this standard. {note}
+
+## The following are governed elsewhere and are outside this standard: {note}
+
+- switchboards, switchgear, and motor control centers, under [[sync/low-voltage-switchboards]], [[sync/low-voltage-switchgear]], and [[sync/motor-control-centers]]
+- enclosed switches and circuit breakers used as individual disconnects, under [[sync/enclosed-switches-and-disconnects]]
+- the feeders and branch circuit conductors that land in the panelboard and their terminations, under [[sync/conductors-and-cables]]
+- the raceways entering the cabinet, under [[sync/raceways-and-conduit]]
+- the grounding electrode system, the equipment grounding conductors, and the bonding of a separately derived system, under [[sync/grounding-and-bonding]]
+- the service point, the service conductors, and the utility metering, under [[sync/electrical-service-entrance]]
+- the surge protective device as a product, its ratings, its protection modes, and its lead length, under [[sync/surge-protective-devices]]
+- the meters, their accuracy class, their current transformers, and the monitoring system they report to, under [[sync/electrical-power-monitoring]]
+- the transformer feeding a panelboard and the grounding of its secondary, under [[sync/low-voltage-dry-type-transformers]]
+- the receptacles, switches, and outlet devices on the branch circuits, under [[sync/wiring-devices]]
+- the remotely operated breakers, relays, and controllers of a lighting-control panelboard, under [[sync/lighting-controls]]
+- the short-circuit, coordination, and arc-flash studies, under [[sync/short-circuit-study]], [[sync/protective-coordination-study]], and [[sync/arc-flash-study]]
+- the room the panelboard occupies, under [[sync/electrical-rooms]]
+
+## Panelboards shall comply with NEMA PB 1 and shall be listed and labeled to UL 67 by a Nationally Recognized Testing Laboratory.
+
+## The location of each panelboard shall be as indicated on [[drawing: the electrical plans]].
+
+## The voltage, the bus rating, the main device, the number of circuits, and the branch circuit devices of each panelboard shall be as indicated on [[drawing: the panel schedules]].
+
+## Where a value stated on a panel schedule for a particular panelboard differs from the datasheet selection under this standard, the panel schedule shall govern for that panelboard.
+
+# Referenced Standards {toc}
+
+## Equipment, materials, and installation shall comply with the latest adopted edition of each of the following unless a specific edition is cited.
+
+## Where the contract documents, the serving utility's requirements, the Authority Having Jurisdiction, or two referenced standards impose conflicting requirements, the more stringent requirement shall govern unless the Engineer of Record directs otherwise in writing.
+
+| Standard | Title |
+|----------|-------|
+| UL 67 | Panelboards |
+| UL 489 | Molded-Case Circuit Breakers, Molded-Case Switches, and Circuit-Breaker Enclosures |
+| UL 943 | Ground-Fault Circuit-Interrupters |
+| UL 1053 | Ground-Fault Sensing and Relaying Equipment |
+| UL 1699 | Arc-Fault Circuit-Interrupters |
+| UL 50 | Enclosures for Electrical Equipment, Non-Environmental Considerations |
+| UL 50E | Enclosures for Electrical Equipment, Environmental Considerations |
+| NEMA PB 1 | Panelboards |
+| NEMA PB 1.1 | General Instructions for Proper Installation, Operation and Maintenance of Panelboards Rated 1000 Volts or Less |
+| NEMA AB 1 | Molded-Case Circuit Breakers, Molded-Case Switches, and Circuit-Breaker Enclosures |
+| NEMA 250 | Enclosures for Electrical Equipment (1000 Volts Maximum) |
+| NFPA 70 | National Electrical Code (Articles 110, 210, 215, 220, 230, 240, 250, 312, 408, 700, 701, and 708) |
+| NFPA 70E | Standard for Electrical Safety in the Workplace |
+| ASTM B187 | Copper, Bus Bar, Rod, and Shapes and General Purpose Rod, Bar, and Shapes |
+| ASTM B317 | Aluminum-Alloy Extruded Bar, Rod, Tube, Pipe, Structural Profiles, and Profiles for Electrical Purposes (Bus Conductor) |
+| ANSI/NETA ATS | Standard for Acceptance Testing Specifications for Electrical Power Equipment and Systems |
+| ASCE 7 | Minimum Design Loads and Associated Criteria for Buildings and Other Structures (Chapter 13) |
+| ICC-ES AC156 | Acceptance Criteria for Seismic Certification by Shake-Table Testing of Nonstructural Components |
+
+# Submittals {toc}
+
+## Action Submittals {toc}
+
+### The Contractor shall submit the following for review before any panelboard is released for manufacture:
+
+- product data for the panelboard, the main device, the branch circuit devices, and every accessory, identifying the UL 67 listing and, where the panelboard is service equipment, the service equipment listing
+- shop drawings for each panelboard giving the cabinet dimensions, the mounting arrangement, the front trim, the bus material and rating, the device arrangement, and the conduit entry areas
+- a panel schedule for each panelboard giving every circuit number, the load served, the pole count, the frame size, the trip rating, and the trip unit type of every device, and every spare and space position
+- the assembly short-circuit current rating of each panelboard and the basis on which it is established, and where the basis is a series rating, the tested combination and the upstream device on which each rating depends
+- the seismic certification for the panelboard as furnished, where the datasheet requires one
+- product data for the surge protective device and the metering furnished within the cabinet, where either is furnished
+- the nameplate schedule listing the text to appear on each panelboard nameplate
+
+```datasheet
+label: Action Submittals
+type: checkbox
+options:
+ - "Product data with UL 67 listing"
+ - "Shop drawings"
+ - "Panel schedules"
+ - "Short-circuit current rating basis and series-rated combinations"
+ - "Seismic certification"
+ - "Surge protective device and metering product data"
+ - "Nameplate schedule"
+default:
+ - "Product data with UL 67 listing"
+ - "Shop drawings"
+ - "Panel schedules"
+ - "Short-circuit current rating basis and series-rated combinations"
+ - "Nameplate schedule"
+```
+
+### A panelboard shall not be released for manufacture until the action submittals covering it have been reviewed and returned.
+
+### The short-circuit current rating is the submittal item that most often comes back wrong, because a catalog rating is the rating of the highest-rated device the cabinet accepts, and the rating that applies to the panelboard is the lowest rating among the bus, the main device, and every branch device actually installed, or the series-rated combination that covers them. {note}
+
+## Informational Submittals {toc}
+
+### The Contractor shall submit the following with or before the action submittals:
+
+- the manufacturer's qualification statement required under Quality Assurance
+- the qualifications of the firm and the technicians who will perform field acceptance testing
+- the factory test procedure, where the datasheet selects witnessed factory testing
+- the manufacturer's published derating factors applied for ambient temperature and altitude, where either exceeds the rating basis of the listing
+
+```datasheet
+label: Informational Submittals
+type: checkbox
+options:
+ - "Manufacturer's qualification statement"
+ - "Field testing firm and technician qualifications"
+ - "Factory test procedure"
+ - "Ambient and altitude derating factors"
+default:
+ - "Manufacturer's qualification statement"
+ - "Field testing firm and technician qualifications"
+```
+
+## Closeout Submittals {toc}
+
+### The Contractor shall submit the following before any panelboard is accepted:
+
+- the record panel schedule for each panelboard, reflecting every as-installed circuit assignment and every field change
+- the certified factory test report, where the datasheet selects witnessed factory testing
+- the field acceptance test report for each panelboard, giving every measured value, the acceptance criterion applied, and the tester's determination
+- the ground-fault protection performance test record required by NFPA 70 230.95(C), where ground-fault protection of equipment is furnished
+- the final settings of every adjustable trip unit
+- operation and maintenance data covering the panelboard, the devices installed in it, and the inspection and re-torque intervals of NEMA PB 1.1
+- the warranty certificate identifying each panelboard by designation and the warranty commencement date
+- a signed receipt from the Owner for the spare parts and keys delivered
+
+```datasheet
+label: Closeout Submittals
+type: checkbox
+options:
+ - "Record panel schedules"
+ - "Certified factory test report"
+ - "Field acceptance test reports"
+ - "Ground-fault protection performance test record"
+ - "Final trip unit settings"
+ - "Operation and maintenance data"
+ - "Warranty certificate"
+ - "Spare parts and keys receipt"
+default:
+ - "Record panel schedules"
+ - "Field acceptance test reports"
+ - "Final trip unit settings"
+ - "Operation and maintenance data"
+ - "Warranty certificate"
+ - "Spare parts and keys receipt"
+```
+
+### The record panel schedule is the document the next electrician reads before opening the cover, and a panelboard whose circuit assignments exist only in the directory card in its door loses them with the first card that is replaced. {note}
+
+# Quality Assurance {toc}
+
+## Manufacturer Qualifications {toc}
+
+### The panelboard shall be produced by a manufacturer that has held a UL 67 listing for panelboards of the type furnished for not less than the period indicated in the datasheet.
+
+```datasheet
+label: Minimum Manufacturer Listing History
+type: range
+unit: years
+options:
+ min: 0
+ max: 20
+ setpoints: [0, 3, 5, 10, 20]
+default: 5
+```
+
+### The manufacturer shall maintain a technical service organization able to reach the site, and shall state in the qualification statement the location of the nearest service center and the period for which replacement devices for the panelboard platform will remain available.
+
+## Source Limitations {toc}
+
+### The cabinet, the interior, the bus, and the branch circuit devices of every panelboard shall be furnished by the panelboard manufacturer under one UL 67 listing.
+
+### Every panelboard on the project shall be furnished by one manufacturer, so that spare devices interchange and the Owner maintains one device family.
+
+### A branch circuit device from another maker shall be installed in a panelboard only where the panelboard manufacturer has listed the device for the interior under UL 67, and the assembly short-circuit current rating with that device installed shall be stated in the action submittals.
+
+### A breaker that fits the bus stab is not a breaker that is listed for the panelboard; the UL 67 listing covers the interior with the specific devices evaluated in it, and an unlisted device removes the panelboard from the condition under which its short-circuit current rating was established. {note}
+
+## Field Testing Firm {toc}
+
+### Field acceptance testing shall be performed by the firm indicated in the datasheet.
+
+```datasheet
+label: Field Acceptance Testing Firm
+type: radio
+options:
+ - "Independent testing firm accredited to ANSI/NETA ATS"
+ - "Manufacturer's field service organization"
+ - "Installing contractor's own technicians"
+```
+
+### The technicians who perform field acceptance testing shall hold a current certification for low-voltage equipment testing from NETA or from the manufacturer of the equipment tested.
+
+### An independent firm has no stake in whether the panelboard passes and reports against a published acceptance standard; the manufacturer's organization knows the product best; the installing contractor's own technicians cost least and are available on the installer's schedule. Which of these the Owner wants depends on how the results will be used and on whether a report from the party who installed the equipment would satisfy the Owner's insurer and the Authority Having Jurisdiction. {note}
+
+# Environmental and Service Conditions {toc}
+
+## Ambient Temperature {toc}
+
+### The panelboard shall carry its nameplate ratings continuously at the design ambient temperature of the space it is installed in.
+
+### The design ambient temperature for a panelboard installed indoors shall be as indicated in the datasheet.
+
+```datasheet
+label: Indoor Design Ambient Temperature
+type: range
+unit: °C
+options:
+ min: 25
+ max: 55
+ setpoints: [25, 30, 40, 50, 55]
+default: 40
+```
+
+### Molded-case circuit breakers are calibrated at a 40 °C ambient under UL 489, so a 40 °C design ambient is the condition at which the device ratings apply without correction; a higher value covers a rooftop mechanical room or an unventilated closet whose ambient cannot be held at 40 °C at design load, at the cost of a larger bus or a larger device for the same load. {note}
+
+### A panelboard installed outdoors or in a space that follows the outdoor temperature shall be rated for [[parameter: site-ambient-temperature-maximum]] where that temperature exceeds 40 °C, and the manufacturer shall state the derating applied in the action submittals.
+
+## Altitude {toc}
+
+### The panelboard and its devices shall be derated for [[parameter: altitude]] in accordance with the manufacturer's published correction factors where the altitude exceeds the 2000 m rating basis of the listing.
+
+### Air thins with altitude, which reduces both the convective cooling that sets the continuous current rating of a device and the dielectric strength of the clearances inside the cabinet, so a panelboard rated at sea level carries less current and less insulation margin at elevation than its nameplate states. {note}
+
+### Ambient temperature derating and altitude derating shall be applied cumulatively where both conditions apply.
+
+## Condensation Control {toc}
+
+### The space heater provision for the cabinet shall be as indicated in the datasheet.
+
+```datasheet
+label: Cabinet Space Heater
+type: radio
+options:
+ - "No space heater"
+ - "Thermostatically controlled space heater"
+```
+
+### A panelboard that stands in an unconditioned space cycles through the dew point with every cold night, and the condensation that forms on the bus, the device terminals, and the insulating supports is the mechanism behind most tracking failures on outdoor and unheated panelboards. {note}
+
+### Where the panelboard is installed outdoors or in a space that is not conditioned, a space heater shall be furnished unless the datasheet selects no space heater.
+
+### Where a space heater is furnished, it shall be sized to hold the interior of the cabinet above the dew point at [[parameter: site-ambient-temperature-minimum]], and shall be supplied from a circuit that stays energized while the panelboard main device is open.
+
+## Seismic Qualification {toc}
+
+### The seismic certification required for the panelboard shall be as indicated in the datasheet.
+
+```datasheet
+label: Seismic Certification Requirement
+type: select
+derived: "[[parameter: seismic-design-category]] and the component importance factor assigned to the panelboard under ASCE 7 Chapter 13"
+options:
+ - "Not required"
+ - "Anchorage design only per ASCE 7 Chapter 13"
+ - "Special seismic certification by shake-table test per ICC-ES AC156 or by analysis accepted by the Authority Having Jurisdiction"
+default: derived
+```
+
+### Anchorage keeps the panelboard on its wall or floor; special certification demonstrates that the devices in it still function after the design earthquake, which ASCE 7 requires of a component whose importance factor is above 1.0, such as a panelboard serving egress lighting, a fire pump, smoke control, or another load a Risk Category IV facility depends on. {note}
+
+### Where seismic certification is required, it shall be performed in accordance with the seismic provisions of [[parameter: adopted-building-code]] and ASCE 7 Chapter 13, and the certificate shall cover the panelboard as furnished, including the cabinet, the interior, and the devices installed.
+
+### A field change to the devices installed or to the mounting that departs from the certified configuration shall be re-evaluated by the manufacturer against the certification before the panelboard is energized.
+
+# Electrical Ratings {toc}
+
+## Service Configuration {toc}
+
+### Whether the panelboard is service equipment shall be as indicated in the datasheet.
+
+```datasheet
+label: Service Configuration
+type: radio
+drawing_ref: "the one-line diagram"
+options:
+ - "Service equipment"
+ - "Downstream distribution equipment"
+default: deferred
+```
+
+### Where the panelboard is service equipment, it shall be listed as suitable for use as service equipment and shall comply with NFPA 70 Article 230, including the service disconnecting means, the available fault current marking, the main bonding jumper, and the grounding electrode conductor termination furnished under [[sync/electrical-service-entrance]] and [[sync/grounding-and-bonding]].
+
+### Where the panelboard is service equipment, the number of service disconnects in the cabinet shall not exceed the number NFPA 70 230.71 permits for the service, and each shall be marked as a service disconnect.
+
+## System Voltage and Frequency {toc}
+
+### The system voltage and configuration shall be as indicated in the datasheet.
+
+```datasheet
+label: System Voltage
+type: select
+drawing_ref: "the panel schedules"
+options:
+ - "120/240 V 1Φ 3-wire"
+ - "208Y/120 V 1Φ 3-wire, two phases and neutral"
+ - "208Y/120 V 3Φ 4-wire"
+ - "240 V 3Φ 3-wire delta"
+ - "240/120 V 3Φ 4-wire high-leg delta"
+ - "480Y/277 V 3Φ 4-wire"
+ - "480 V 3Φ 3-wire delta"
+ - "600Y/347 V 3Φ 4-wire"
+ - "600 V 3Φ 3-wire delta"
+default: deferred
+```
+
+### The number of phases and the number of wires follow from the system voltage selected, and the number of poles on the main device and the presence of a neutral bus follow from them in turn. {note}
+
+### The panelboard voltage rating shall equal or exceed the system voltage, and where the panelboard is fed from a transformer secondary the Contractor shall confirm the rating against the secondary configuration selected under [[sync/low-voltage-dry-type-transformers]] before the panelboard is released for manufacture.
+
+### Where the system is a high-leg delta, the high leg shall be connected to the B phase of the bus, shall be identified in accordance with NFPA 70 110.15 and 408.3(F), and single-pole devices shall not be installed on the high-leg phase.
+
+### Where the system is a 3-wire delta or another system with no grounded conductor at the panelboard, the panelboard shall be furnished without a neutral bus and the devices shall be rated for the line-to-line voltage.
+
+### The system frequency shall be as indicated in the datasheet.
+
+```datasheet
+label: System Frequency
+type: radio
+options:
+ - "60 Hz"
+ - "50 Hz"
+default: "60 Hz"
+```
+
+## Main Bus Continuous Current {toc}
+
+### The main bus continuous current rating shall be as indicated in the datasheet.
+
+```datasheet
+label: Main Bus Continuous Current
+type: range
+unit: A
+drawing_ref: "the panel schedules"
+options:
+ min: 60
+ max: 1600
+ setpoints: [60, 100, 125, 150, 200, 225, 250, 400, 600, 800, 1000, 1200, 1600]
+default: deferred
+```
+
+### The main bus rating shall be not less than the rating of the main device where one is furnished, and not less than the rating of the feeder overcurrent device where the panelboard has main lugs only.
+
+### The bus rating is fixed per panelboard by the calculated load of NFPA 70 Article 220 and the spare capacity the project wants to leave, and it is stated on the panel schedule with the main device that protects it; the datasheet field records the rating only where one rating applies across the project. {note}
+
+## Short-Circuit Current Rating {toc}
+
+### The available fault current at the line terminals of each panelboard shall be as indicated on [[drawing: the panel schedules]].
+
+### The assembly short-circuit current rating marked on the nameplate of each panelboard shall equal or exceed the available fault current at its line terminals as established under [[sync/short-circuit-study]], and shall be as indicated in the datasheet.
+
+```datasheet
+label: Assembly Short-Circuit Current Rating
+type: range
+unit: kA
+drawing_ref: "the panel schedules"
+options:
+ min: 10
+ max: 200
+ setpoints: [10, 14, 18, 22, 25, 30, 35, 42, 50, 65, 85, 100, 150, 200]
+default: deferred
+```
+
+### The marked assembly rating is the lowest of the bus bracing, the interrupting rating of the main device, and the interrupting rating of every branch device, or the rating of the series-rated combination that covers them, so a single device of a lower rating installed in the field lowers the rating of the whole panelboard. {note}
+
+### The bus short-circuit bracing shall be as indicated in the datasheet.
+
+```datasheet
+label: Bus Short-Circuit Bracing
+type: range
+unit: kA
+derived: "the assembly short-circuit current rating; the bus is braced to not less than the rating marked on the panelboard"
+options:
+ min: 10
+ max: 200
+ setpoints: [10, 14, 18, 22, 25, 30, 35, 42, 50, 65, 85, 100, 150, 200]
+default: derived
+```
+
+### The available fault current at each panelboard is a property of the source, the transformer, and the feeder ahead of it, and it is recalculated when any of those change; the study establishes it, the panel schedule carries it, and the panelboard is rated against it. {note}
+
+## Interrupting Rating Basis {toc}
+
+### The basis on which the interrupting ratings of the devices in the panelboard are established shall be as indicated in the datasheet.
+
+```datasheet
+label: Interrupting Rating Basis
+type: radio
+options:
+ - "Fully rated"
+ - "Series rated"
+```
+
+### In a fully rated panelboard every device carries an interrupting rating that stands on its own at the available fault current; in a series-rated panelboard the branch devices carry a lower individual rating and reach the marked rating only in combination with the specific upstream device they were tested with, which NFPA 70 240.86 permits where the combination is listed. Series rating lowers the cost of the branch devices where the available fault current is high, and it makes the rating depend on an upstream device that must stay in place for the life of the installation; full rating costs more per device and depends on nothing upstream. {note}
+
+### The interrupting rating of the branch circuit devices shall be as indicated in the datasheet.
+
+```datasheet
+label: Branch Circuit Device Interrupting Rating
+type: range
+unit: kA
+derived: "the assembly short-circuit current rating and the interrupting rating basis; under a fully rated basis every device equals or exceeds the assembly rating, and under a series rated basis the listed combination fixes the branch device rating"
+options:
+ min: 10
+ max: 200
+ setpoints: [10, 14, 18, 22, 25, 30, 35, 42, 50, 65, 85, 100, 150, 200]
+default: derived
+```
+
+### Where series rating is the basis, the combination shall be one the manufacturer has tested and listed under UL 67 and UL 489 in accordance with NFPA 70 240.86(B), and the upstream device on which each rating depends shall be identified in the action submittals.
+
+### Where series rating is the basis, the panelboard shall be field-marked in accordance with NFPA 70 110.22(C) to identify the series combination and the replacement devices it depends on.
+
+### Where series rating is the basis, the Contractor shall confirm that the sum of the motor full-load currents connected between the upstream device and the panelboard does not exceed the limit NFPA 70 240.86(C) sets for the branch device rating, and shall report a combination that exceeds it to the Engineer of Record before the panelboard is released for manufacture.
+
+### Where the panelboard serves a system that NFPA 70 Article 700, 701, or 708 requires to be selectively coordinated, a series-rated combination shall not be relied on within the coordinated path, because the upstream device of a series combination opens with the branch device on a high-magnitude fault.
+
+### Where a device in a series-rated panelboard is replaced, the replacement shall be of the same manufacturer, type, and rating named in the listed combination.
+
+# Main Device {toc}
+
+## Main Device Type {toc}
+
+### The main device of the panelboard shall be as indicated in the datasheet.
+
+```datasheet
+label: Main Device Type
+type: select
+drawing_ref: "the panel schedules"
+options:
+ - "Main lugs only"
+ - "Main circuit breaker"
+ - "Main fusible switch"
+default: deferred
+```
+
+### The main device frame size and trip rating, or the switch and fuse rating, shall be as indicated on [[drawing: the panel schedules]].
+
+### A main circuit breaker gives the panelboard a disconnecting means and an overcurrent device at the cabinet, which is what a service disconnect, a tenant disconnect, and a panelboard whose feeder device is out of sight or out of reach each need; main lugs only leaves both functions to the feeder device upstream and saves the cost and the cabinet height of the main; a main fusible switch is the construction used where the fault current calls for a current-limiting fuse or where the Owner's device family is fused. {note}
+
+### Where the panelboard has main lugs only, it shall be protected by an overcurrent device on the supply side whose rating does not exceed the bus rating, in accordance with NFPA 70 408.36, and that device shall be accessible as the disconnecting means for the panelboard.
+
+### Where the panelboard is service equipment, the main device shall be the service disconnecting means and shall be rated in accordance with NFPA 70 Article 230.
+
+### The main device operating handle shall accept a padlock in the open position.
+
+## Main Circuit Breaker Trip Unit {toc}
+
+### Where a main circuit breaker is furnished, its trip unit shall be as indicated in the datasheet.
+
+```datasheet
+label: Main Circuit Breaker Trip Unit
+type: select
+drawing_ref: "the panel schedules"
+options:
+ - "Thermal-magnetic"
+ - "Electronic with long-time and instantaneous functions"
+ - "Electronic with long-time, short-time, and instantaneous functions"
+ - "Electronic with long-time, short-time, instantaneous, and ground-fault functions"
+default: deferred
+```
+
+### A thermal-magnetic trip unit has a fixed time-current characteristic, an instantaneous setting that is adjustable on the larger frames only, and no communications, and it is the construction the smaller frames are built with; an electronic trip unit has adjustable long-time, short-time, and instantaneous settings, which is what selective coordination with the upstream device is set with, and it is the construction the larger frames are built with; the ground-fault function on an electronic trip unit is one of the two ways ground-fault protection of equipment is furnished where code requires it. {note}
+
+### Where a main circuit breaker with an electronic trip unit is furnished, its settings shall be as established under [[sync/protective-coordination-study]], and the settings as commissioned shall be recorded in the closeout submittals.
+
+## Ground-Fault Protection of Equipment {toc}
+
+### Ground-fault protection of equipment on the main device shall be as indicated in the datasheet.
+
+```datasheet
+label: Ground-Fault Protection of Equipment on the Main Device
+type: select
+derived: "NFPA 70 230.95 and 215.10 applied to the system voltage, the main device rating, and whether the panelboard is service equipment"
+options:
+ - "Not provided"
+ - "Integral to the main circuit breaker electronic trip unit"
+ - "Separate ground-fault relay and sensor listed to UL 1053"
+default: derived
+```
+
+### Whether the main device must carry ground-fault protection of equipment is fixed by code from the system grounding, the voltage to ground, and the device rating, so the field records the consequence of those inputs rather than a preference; a project may add ground-fault protection where code does not require it, and where it is required the means of providing it is the project selection. {note}
+
+### Where ground-fault protection of equipment is furnished, it shall open all ungrounded conductors of the panelboard at a ground-fault pickup not exceeding 1200 A and within one second for a ground-fault current of 3000 A or more, in accordance with NFPA 70 230.95(A).
+
+### Where ground-fault protection of equipment is furnished on a panelboard that is not service equipment, its pickup and delay shall be set to coordinate with the ground-fault protection upstream as established under [[sync/protective-coordination-study]].
+
+### Where ground-fault protection of equipment is furnished, the Contractor shall have it performance-tested by primary current injection after installation in accordance with NFPA 70 230.95(C), and the written record shall be delivered with the closeout submittals.
+
+### Ground-fault protection of equipment protects the bus and the conductors from the arcing damage of a low-magnitude ground fault that the main device would not clear promptly; it does not protect a person, and it is not a substitute for the ground-fault circuit-interrupter protection NFPA 70 210.8 requires on branch circuits. {note}
+
+## Arc Energy Reduction {toc}
+
+### Where a circuit breaker in the panelboard is rated or can be adjusted to 1200 A or more, arc energy reduction shall be provided in accordance with NFPA 70 240.87 by the method indicated in the datasheet.
+
+```datasheet
+label: Arc Energy Reduction Method
+type: select
+derived: "NFPA 70 240.87 applied to the rating of the main device and of each feeder device shown on the panel schedules"
+options:
+ - "Not applicable, no device rated 1200 A or more"
+ - "Energy-reducing maintenance switching with local status indicator"
+ - "Zone-selective interlocking"
+ - "Differential relaying"
+ - "Energy-reducing active arc-flash mitigation system"
+ - "Instantaneous trip setting below the available arcing current"
+default: derived
+```
+
+### Whether arc energy reduction is required is fixed by the device rating, so the field carries the consequence of the panel schedules; only the method is a project selection where the threshold is met. {note}
+
+### An energy-reducing maintenance switch lowers the instantaneous pickup for the duration of the work and depends on a worker turning it on; zone-selective interlocking and differential relaying act without a worker's intervention but need the downstream devices or the current transformers to be part of the scheme; an active mitigation system detects the arc by light and current and clears it faster than any trip unit, at the highest cost; an instantaneous setting below the arcing current works only where the arcing current at the panelboard is well above the load current. {note}
+
+### Where energy-reducing maintenance switching is selected, the switch shall be lockable in the maintenance position and its status shall be indicated at the switch.
+
+### Where arc energy reduction is furnished, the Contractor shall perform the performance test NFPA 70 240.87(C) requires and shall deliver the documentation NFPA 70 240.87(A) requires with the closeout submittals.
+
+# Bus {toc}
+
+## Phase Bus Material {toc}
+
+### The phase bus material shall be as indicated in the datasheet.
+
+```datasheet
+label: Phase Bus Material
+type: radio
+options:
+ - "Copper"
+ - "Aluminum"
+```
+
+### Copper bus carries more current per unit cross-section, has the lower contact resistance at a bolted joint, and costs more; aluminum bus is lighter and less expensive for the same rating, and its joints depend on the plating and on the joint hardware to hold their resistance through thermal cycling, which is why aluminum is chosen where the cost difference on a large bus matters and copper is chosen where the joint count is high or the environment attacks aluminum. {note}
+
+### Where copper bus is selected, it shall be copper bus bar conforming to ASTM B187 with a conductivity of not less than 98% IACS.
+
+### Where aluminum bus is selected, it shall be an aluminum alloy bus conductor conforming to ASTM B317 with a conductivity of not less than 55% IACS, and shall be plated over its full length.
+
+### A joint between an aluminum bus and a copper conductor or terminal shall be made with a connector listed for the combination.
+
+## Bus Plating {toc}
+
+### The bus plating shall be as indicated in the datasheet.
+
+```datasheet
+label: Bus Plating
+type: radio
+options:
+ - "Unplated"
+ - "Tin-plated"
+ - "Silver-plated"
+default: manufacturer
+```
+
+### The manufacturer shall state the plating in the product data.
+
+### Unplated copper bus holds its contact resistance in a clean, dry interior and is the construction most panelboards are built with; tin plating resists the sulfur compounds that blacken silver and raise its contact resistance, and is the plating that holds its resistance where the atmosphere carries hydrogen sulfide, as in a wastewater facility; silver plating has the lowest contact resistance in a clean atmosphere. Aluminum bus is plated in every construction because its oxide forms within minutes of exposure and is an insulator. {note}
+
+### Where plating is furnished, it shall be continuous over every bolted joint contact surface and over the full length of the device stab contact area.
+
+## Neutral Bus {toc}
+
+### The neutral bus shall be as indicated in the datasheet.
+
+```datasheet
+label: Neutral Bus
+type: select
+derived: "the system voltage configuration and the share of nonlinear load served from the panelboard"
+options:
+ - "No neutral bus"
+ - "Neutral bus rated 100% of the phase bus"
+ - "Neutral bus rated 200% of the phase bus"
+default: derived
+```
+
+### A three-wire system has no neutral to carry, a four-wire system carries one rated with the phase bus, and a four-wire system whose load is predominantly single-phase nonlinear equipment, such as switch-mode power supplies, LED drivers, and single-phase drives, carries the triplen harmonic currents that add in the neutral rather than cancel, which is the condition under which the neutral is rated above the phase bus. {note}
+
+### Where a neutral bus is furnished, it shall be insulated from the cabinet, and where the panelboard is service equipment the main bonding jumper shall be furnished by the manufacturer and installed in accordance with [[sync/grounding-and-bonding]].
+
+### Where a neutral bus is furnished, it shall have not fewer than one terminal for every branch circuit position in the panelboard, and each neutral conductor shall be terminated in its own terminal in accordance with NFPA 70 408.41.
+
+### Where a neutral bus rated 200% of the phase bus is furnished, its terminals and the feeder neutral lug shall be sized for the neutral conductor that the rating implies.
+
+## Equipment Ground Bus {toc}
+
+### Each panelboard shall be furnished with an equipment grounding terminal bar bonded to the cabinet, with not fewer than one terminal for every branch circuit position, in accordance with NFPA 70 408.40.
+
+### Whether an isolated equipment ground bus is furnished shall be as indicated in the datasheet.
+
+```datasheet
+label: Isolated Equipment Ground Bus
+type: radio
+options:
+ - "Not furnished"
+ - "Furnished"
+default: "Not furnished"
+```
+
+### An isolated equipment ground bus is mounted on insulating standoffs so that the isolated grounding conductors of the circuits that use it return to the grounding point of the derived system without picking up the noise currents on the cabinet; it serves the isolated-ground receptacle circuits of NFPA 70 250.146(D), and a bus furnished where no such circuit exists adds cost and invites a termination on the wrong bar. {note}
+
+### Where an isolated equipment ground bus is furnished, it shall be insulated from the cabinet, shall be identified as the isolated ground bus, and shall be connected as [[sync/grounding-and-bonding]] requires for the circuits it serves.
+
+### Grounding and bonding of the panelboard shall comply with [[sync/grounding-and-bonding]].
+
+## Bus Arrangement and Bracing {toc}
+
+### The phase bus shall be arranged so that the phase sequence is A, B, C from front to back, top to bottom, or left to right as viewed from the front, in accordance with NFPA 70 408.3(E).
+
+### The bus shall be of distributed-phase construction, so that a two-pole or three-pole device installed at any listed position connects to adjacent phases in sequence.
+
+### The bus shall be supported on insulating supports that withstand the bus short-circuit bracing indicated in the datasheet without damage, and the bus and its supports shall be rated for the system voltage.
+
+### Bus joints shall be bolted with hardware that maintains contact pressure through thermal cycling, and the joint hardware and torque shall be those established under the listing.
+
+### Every unused device position on the bus shall be covered by a filler plate in the front when the panelboard is delivered, so that no bus stab is exposed with the door open.
+
+## Feed-Through and Sub-Feed Provisions {toc}
+
+### Feed-through lugs, sub-feed lugs, and sub-feed breakers shall be furnished on the panelboards indicated on [[drawing: the panel schedules]].
+
+### Where feed-through lugs are furnished, they shall be rated for the full bus current, shall be mounted on the load end of the bus, and shall accept the conductor size and count indicated on the panel schedule.
+
+### Where a panelboard is furnished in two sections because its circuit count exceeds one cabinet, both sections shall carry the full bus rating, the second section shall be fed from the first through sub-feed lugs or a sub-feed breaker furnished by the manufacturer, and the two sections shall carry one panelboard designation with a section suffix.
+
+### A feed-through lug passes the full bus current on to a second panelboard without a device at the first, so the feeder device upstream protects both; a sub-feed breaker adds a device at the first panelboard so that the second is protected and can be isolated on its own. {note}
+
+# Cabinet and Front {toc}
+
+## Enclosure Type {toc}
+
+### The enclosure type shall be as indicated in the datasheet.
+
+```datasheet
+label: Enclosure Type per NEMA 250
+type: select
+options:
+ - "Type 1"
+ - "Type 2"
+ - "Type 3R"
+ - "Type 4"
+ - "Type 4X"
+ - "Type 12"
+default: "Type 1"
+```
+
+### A dry, conditioned interior space is the installed location on most projects, which is why Type 1 is the default; every other location named in the clauses of this article calls for the type those clauses require. {note}
+
+### The cabinet shall comply with UL 50 and, for a type other than Type 1, with UL 50E and NEMA 250 for the type selected, and the type shall be marked on the cabinet.
+
+### A panelboard installed outdoors shall have an enclosure of Type 3R, Type 4, or Type 4X.
+
+### A panelboard installed where it is subject to hose-directed water or wash-down shall have an enclosure of Type 4 or Type 4X.
+
+### A panelboard installed where the atmosphere carries salt, chemical vapor, or another corrosive agent, including a coastal site, a wastewater facility, and a food-processing area, shall have a Type 4X enclosure.
+
+### A panelboard installed indoors where airborne dust, lint, or fibers accumulate shall have an enclosure of Type 12, Type 4, or Type 4X.
+
+### A panelboard installed indoors where dripping or light splashing of a non-corrosive liquid occurs shall have an enclosure of Type 2, Type 12, Type 4, or Type 4X.
+
+### Where a rating higher than the datasheet selection is required by the clauses of this article for the installed location, the higher rating shall be furnished and the conflict reported to the Engineer of Record before the panelboard is released for manufacture.
+
+### A field opening cut in a Type 3R, Type 4, Type 4X, or Type 12 cabinet other than at a location and by a method the listing permits removes the environmental rating, and the rework is charged to the party that made the cut. {note}
+
+## Enclosure Material and Finish {toc}
+
+### The cabinet material shall be as indicated in the datasheet.
+
+```datasheet
+label: Cabinet Material
+type: select
+options:
+ - "Galvanized steel with painted front"
+ - "Painted steel"
+ - "Type 304 stainless steel"
+ - "Type 316 stainless steel"
+ - "Non-metallic"
+default: "Galvanized steel with painted front"
+```
+
+### A galvanized steel box with a painted front is the construction the indoor panelboard is built with, and it serves every enclosure type in a non-corrosive exposure; stainless steel and non-metallic cabinets are what a Type 4X rating is built in, with Type 316 holding up where chlorides are present and a non-metallic cabinet holding up where the corrodent attacks stainless steel. {note}
+
+### Where the datasheet selects a Type 4X enclosure, the cabinet material shall be one for which the Type 4X rating is listed.
+
+### The cabinet and the front shall be formed from steel of not less than the thickness UL 50 requires for the cabinet dimensions, and the front shall be reinforced so that the door does not deflect when opened.
+
+### The finish color of the front shall be as indicated in the datasheet.
+
+```datasheet
+label: Front Finish Color
+type: select
+options:
+ - "ANSI 61 light gray"
+ - "ANSI 49 medium gray"
+ - "White"
+ - "Custom color matched to a sample furnished by the Owner"
+default: "ANSI 61 light gray"
+```
+
+### A painted front shall carry a baked powder coat or enamel finish over a phosphate pretreatment, and the manufacturer shall state the finish system in the product data.
+
+## Mounting Arrangement {toc}
+
+### The mounting arrangement shall be as indicated in the datasheet.
+
+```datasheet
+label: Mounting Arrangement
+type: select
+drawing_ref: "the panel schedules"
+options:
+ - "Surface mounted"
+ - "Flush mounted"
+ - "Semi-flush mounted"
+ - "Floor standing"
+default: deferred
+```
+
+### A flush-mounted cabinet is recessed so that the front sits at the finished wall, and once the wall is closed it accepts a new circuit only through a raceway that was left at rough-in; a surface-mounted cabinet stands proud of the wall and accepts a raceway at any time; a floor-standing panelboard is the construction the larger frames are built in and is set on a pad like a switchboard. {note}
+
+### A panelboard shall be furnished floor standing where its frame exceeds the manufacturer's published wall-mount limit, whatever the datasheet selects.
+
+### A column-width panelboard shall be furnished where indicated on [[drawing: the electrical plans]], with its pull box and its device arrangement as the manufacturer lists for that construction.
+
+### Where a flush-mounted panelboard is furnished, the Contractor shall install the number of empty raceways indicated in the datasheet from the cabinet to an accessible location above the ceiling, capped and identified at both ends.
+
+```datasheet
+label: Flush-Mount Spare Raceways
+type: range
+unit: count
+options:
+ min: 0
+ max: 8
+ step: 1
+```
+
+### The spare raceways are the only economical path to a new circuit once a flush-mounted cabinet is walled in, and the count is a judgment about how much future flexibility the Owner is buying at the time the wall is open. {note}
+
+## Front Trim and Door {toc}
+
+### The front construction shall be as indicated in the datasheet.
+
+```datasheet
+label: Front Construction
+type: radio
+options:
+ - "Trim with hinged door"
+ - "Door-in-door trim with hinged trim and hinged door"
+ - "Trim without door"
+default: "Trim with hinged door"
+```
+
+### A trim with a hinged door gives access to the device handles with the trim screwed in place and the bus covered; a door-in-door trim hinges the whole trim as well, so that the interior can be reached for wiring without removing the trim and without exposing the bus to a dropped panel; a trim without a door leaves the device handles exposed and is the construction used in a locked electrical room where the handles are meant to be reached without a key. {note}
+
+### The front shall be of dead-front construction, concealing every energized part and every device line terminal with the door open.
+
+### The door shall be hinged on a continuous hinge, shall open not less than 90 degrees, and shall be fitted with a flush cylinder lock and latch.
+
+### The keying of the door locks shall be as indicated in the datasheet.
+
+```datasheet
+label: Door Lock Keying
+type: radio
+options:
+ - "Keyed alike across the project"
+ - "Keyed to the Owner's existing panelboard key"
+default: "Keyed alike across the project"
+```
+
+### Two keys shall be furnished for each panelboard, and the Contractor shall deliver every key to the Owner against a signed receipt.
+
+### A directory holder with a transparent cover shall be mounted on the inside of the door.
+
+### Where the front is a trim without door, the interior shall be covered by a dead-front that exposes the device handles only.
+
+## Wiring Gutters and Conduit Entry {toc}
+
+### The wiring gutters on every side of the interior shall be sized for the conductors that enter the cabinet in accordance with NFPA 70 312.6, and the box width shall be not less than 20 in.
+
+### Where the panel schedules indicate a conductor size or count for which the standard gutters do not satisfy NFPA 70 312.6, the manufacturer shall furnish a wider or deeper cabinet, and the gutter dimensions shall be shown on the shop drawings.
+
+### Conduit shall enter the cabinet through the top, the bottom, or the side end walls as indicated on [[drawing: the electrical plans]], and a raceway shall not enter through the back of a flush-mounted cabinet.
+
+### A cabinet in a Type 3R, Type 4, or Type 4X enclosure shall be entered only with hubs or fittings listed for the enclosure type, and every unused opening shall be closed with a fitting listed for the type.
+
+### A cabinet shall be furnished with blank end walls for field-punched openings, and the manufacturer shall not furnish concentric or eccentric knockouts on a cabinet of a type other than Type 1.
+
+# Branch Circuit Devices {toc}
+
+## Branch Circuit Breaker Mounting {toc}
+
+### Branch circuit breakers shall be listed to UL 489, and their mounting shall be as indicated in the datasheet.
+
+```datasheet
+label: Branch Circuit Breaker Mounting
+type: radio
+options:
+ - "Bolt-on"
+ - "Plug-on"
+ - "Plug-on with plug-on neutral bus"
+default: "Bolt-on"
+```
+
+### A bolt-on breaker is secured to the bus with a bolt at each pole, which holds its contact pressure through vibration and through repeated operation; a plug-on breaker engages the bus stab with a spring clip and is installed and removed without a tool, at the cost of a connection that depends on the clip's tension; a plug-on neutral interior adds a neutral rail that a ground-fault or arc-fault breaker engages directly, which removes the neutral pigtail those breakers otherwise need. {note}
+
+### Branch circuit breakers shall be the panelboard manufacturer's breakers listed for the interior, and a breaker of another manufacturer shall be installed only as permitted under Source Limitations.
+
+### A breaker shall be installed only in a position the listing designates for its frame and pole count, and a tandem breaker shall be installed only in a position listed to accept it and only where the resulting device count does not exceed the number for which the panelboard is listed, in accordance with NFPA 70 408.54.
+
+### A tandem breaker doubles the circuits in one position but does not raise the listed device count of the panelboard, and installing tandems in positions not listed for them to fit more circuits into a full panelboard is the field expedient that fails inspection. {note}
+
+## Branch Circuit Breaker Ratings {toc}
+
+### The frame size, the pole count, the trip rating, and the trip unit type of every branch circuit breaker shall be as indicated on [[drawing: the panel schedules]].
+
+### Where the panel schedule does not indicate a trip unit type for a branch circuit breaker, the breaker shall be thermal-magnetic.
+
+### Every branch circuit breaker shall be rated for the system voltage, and a single-pole breaker on a system of more than 120 V to ground shall be rated for the line-to-ground voltage of that system.
+
+### A breaker used as the switch for a 120 V or 277 V fluorescent lighting circuit shall be marked SWD or HID, and a breaker used as the switch for a high-intensity discharge lighting circuit shall be marked HID, in accordance with NFPA 70 240.83(D).
+
+### Multi-pole breakers shall be common-trip, so that every pole opens when any pole trips, and identified handle ties on single-pole breakers shall be used in place of a multi-pole breaker only where NFPA 70 240.15(B) permits them.
+
+### Every branch circuit breaker shall have a trip-free mechanism and a handle that indicates the on, off, and tripped positions.
+
+## Spare Positions {toc}
+
+### The share of positions in each panelboard left for future circuits shall be not less than the share indicated in the datasheet, in addition to the spare and space positions the panel schedule designates.
+
+```datasheet
+label: Minimum Spare Branch Circuit Positions
+type: range
+unit: '%'
+options:
+ min: 0
+ max: 30
+ setpoints: [0, 10, 15, 20, 25, 30]
+```
+
+### The form in which spare positions are furnished shall be as indicated in the datasheet.
+
+```datasheet
+label: Spare Position Provision
+type: radio
+options:
+ - "Bussed spaces with filler plates"
+ - "Spare circuit breakers installed"
+```
+
+### A bussed space is a position with its stab or bolt connection in place and a filler plate in the front, ready to receive a breaker of any listed rating; a spare breaker installed is a device bought now, marked spare, and left open, which lets a circuit be added without a purchase but commits the trip rating in advance. {note}
+
+### Where spare circuit breakers are installed, the trip rating and pole count of the spares shall be as indicated on [[drawing: the panel schedules]], and each spare shall be left in the open position and identified as a spare.
+
+### Every space position shall be bussed and provided with the mounting hardware needed to receive a breaker without modifying the interior.
+
+## Personnel Ground-Fault and Arc-Fault Protection {toc}
+
+### The location at which ground-fault circuit-interrupter protection for personnel is provided on the branch circuits NFPA 70 210.8 requires it shall be as indicated in the datasheet.
+
+```datasheet
+label: Personnel Ground-Fault Protection Location
+type: radio
+options:
+ - "Ground-fault circuit-interrupter breakers at the panelboard"
+ - "Ground-fault circuit-interrupter receptacles and devices at the outlet"
+```
+
+### A ground-fault circuit-interrupter breaker protects the whole branch circuit, including its conductors, and is reset at the panelboard; a ground-fault circuit-interrupter receptacle protects the receptacle and the outlets downstream of it, costs less per circuit, and is reset where the person who tripped it is standing. Which is wanted depends on whether the conductors need protection, on who is expected to reset a trip, and on whether the panelboard is accessible to that person. {note}
+
+### Where the panel schedules designate a circuit for a protection location other than the datasheet selection, the panel schedule shall govern for that circuit.
+
+### Where ground-fault circuit-interrupter breakers are furnished, they shall be listed to UL 943 as Class A devices, and the receptacles and devices on those circuits shall comply with [[sync/wiring-devices]].
+
+### The means of arc-fault circuit-interrupter protection on the branch circuits NFPA 70 210.12 requires it shall be as indicated in the datasheet.
+
+```datasheet
+label: Arc-Fault Protection Means
+type: radio
+options:
+ - "Combination-type arc-fault circuit-interrupter breakers at the panelboard"
+ - "Outlet branch-circuit arc-fault circuit-interrupter devices at the first outlet"
+ - "Not applicable, no branch circuit requiring arc-fault protection"
+```
+
+### The branch circuits on which NFPA 70 210.12 requires arc-fault protection shall be as indicated on [[drawing: the panel schedules]].
+
+### Where arc-fault circuit-interrupter breakers are furnished, they shall be combination-type devices listed to UL 1699, and where a circuit requires both arc-fault and ground-fault protection a dual-function breaker listed to both UL 1699 and UL 943 may be furnished in place of two devices.
+
+### Where outlet branch-circuit arc-fault protection is selected, the branch circuit from the panelboard to the first outlet shall be installed by a wiring method NFPA 70 210.12 permits for that arrangement, and the device at the first outlet shall comply with [[sync/wiring-devices]].
+
+## Breaker Accessories {toc}
+
+### Handle lock-on devices, handle padlock provisions, shunt trips, auxiliary contacts, and bell alarms shall be furnished on the branch circuit breakers designated on [[drawing: the panel schedules]].
+
+### A handle lock-on device holds a breaker closed against an unintended manual opening and is the provision NFPA 70 requires on a fire alarm circuit and on other circuits that must not be switched off in error; a shunt trip lets a breaker be opened from a remote contact, as at a kitchen hood suppression system or an emergency power off station; an auxiliary contact reports the breaker position to a control system. {note}
+
+### Where a shunt trip is furnished, the control voltage and the source of the trip signal shall be as indicated on [[drawing: the panel schedules]], and the trip circuit shall be tested through its initiating device before the panelboard is accepted.
+
+### Where the panel schedules designate a panelboard as a lighting-control panelboard, its remotely operated breakers, their controller, and their power supply shall comply with [[sync/lighting-controls]] and shall be installed by the manufacturer in the interior under the UL 67 listing.
+
+# Surge Protection and Metering Provisions {toc}
+
+## Surge Protective Device Provisions {toc}
+
+### Surge protective devices shall be furnished at the panelboards indicated on [[drawing: the one-line diagram]], and the device, its ratings, its protection modes, and its lead length shall comply with [[sync/surge-protective-devices]].
+
+### Where a surge protective device is furnished at a panelboard, its mounting arrangement shall be as indicated in the datasheet.
+
+```datasheet
+label: Surge Protective Device Mounting Arrangement
+type: radio
+options:
+ - "Integral, factory-installed within the cabinet"
+ - "External, mounted adjacent to the cabinet and connected through a dedicated breaker"
+```
+
+### An integral device is connected to the bus by the manufacturer with the shortest lead the cabinet allows, is covered by the panelboard listing, and takes the cabinet with it when it is replaced at end of life; an external device is connected through a breaker with a lead of whatever length the installation produces, is replaced without opening the panelboard, and is the arrangement used where the panelboard is existing or where the Owner standardizes on one device family across equipment of several makers. {note}
+
+### Where an integral surge protective device is furnished, it shall be installed by the panelboard manufacturer under the UL 67 listing, shall be connected to the bus on the load side of the main device, and shall be disconnectable for replacement without de-energizing the panelboard where the listing provides a disconnect for it.
+
+### Where an integral surge protective device is furnished, the device status indication shall be visible with the door closed.
+
+## Metering Provisions {toc}
+
+### The metering furnished within the panelboard shall be as indicated in the datasheet.
+
+```datasheet
+label: Metering Provisions
+type: select
+options:
+ - "No metering"
+ - "Current transformer and meter mounting provisions only"
+ - "Main metering"
+ - "Main and branch-circuit metering"
+default: "No metering"
+```
+
+### Meters, their accuracy class, their current transformers, and their communications shall comply with [[sync/electrical-power-monitoring]], and where metering is furnished within the cabinet it shall be installed by the manufacturer under the UL 67 listing in a compartment separate from the wiring gutters.
+
+### Branch-circuit metering makes the energy of each circuit visible for tenant billing, commissioning, and measurement and verification, at the cost of a current transformer on every circuit and a meter that can read them; main metering records the panelboard as one load; mounting provisions leave the compartment and the current transformer space in place for a meter bought later. {note}
+
+### Where [[parameter: adopted-energy-code]] requires the loads served from the panelboard to be submetered, the metering shall accumulate energy for those loads and shall report it to the building energy monitoring system under [[sync/electrical-power-monitoring]].
+
+# Identification {toc}
+
+## Nameplates, circuit directories, arc-flash labels, and field markings shall comply with [[sync/electrical-identification]] for material, lettering, attachment, and directory format.
+
+## Each panelboard shall carry a nameplate stating the panelboard designation, the system voltage with the number of phases and wires, the main bus rating, the main device rating where one is furnished, the assembly short-circuit current rating, and the source that feeds it, in the text listed on the nameplate schedule.
+
+## The panelboard designation on the nameplate shall match the designation on the panel schedule and on the one-line diagram.
+
+## The manufacturer shall mark on the interior the UL 67 listing, the series-rated combinations where series rating is the basis, and the devices listed for installation in the interior.
+
+## The available fault current at the line terminals and the date it was calculated shall be field-marked on each panelboard that is service equipment, in accordance with NFPA 70 110.24.
+
+## The arc-flash warning label shall carry the values established under [[sync/arc-flash-study]] for the panelboard and shall be placed so that it is read before the door is opened, in accordance with NFPA 70 110.16.
+
+## Where the panelboard serves an emergency, legally required standby, or critical operations power system, it shall be marked as a component of that system in accordance with the article of NFPA 70 that governs the system.
+
+# Testing {toc}
+
+## Factory Tests {toc}
+
+### The manufacturer shall perform the production tests of UL 67 and NEMA PB 1 on every panelboard before shipment, including a dielectric withstand test of the bus, a mechanical operation check of every device, an inspection of every bus joint against the listed torque, and an inspection of the assembly against the reviewed shop drawings.
+
+### Factory test witnessing shall be as indicated in the datasheet.
+
+```datasheet
+label: Factory Test Witnessing
+type: radio
+options:
+ - "Witnessed by the Owner's representative"
+ - "Certified test report without witnessing"
+default: "Certified test report without witnessing"
+```
+
+### Where witnessing is selected, the manufacturer shall give not less than two weeks' notice of test readiness, shall submit the test procedure for review before the test, and shall not ship a panelboard until the witness has accepted the results or has waived attendance in writing.
+
+### A witnessed test lets the Owner see every device operate before the panelboard ships, and it commits a representative to a trip to the factory for each shipment; a certified report records the same tests without the trip, and leaves any discrepancy to be found at field acceptance testing. {note}
+
+## Field Acceptance Tests {toc}
+
+### Field acceptance tests shall be performed on every panelboard after installation is complete and before it is energized, in accordance with ANSI/NETA ATS and [[sync/electrical-acceptance-testing]], and shall include the tests indicated in the datasheet.
+
+```datasheet
+label: Field Acceptance Tests
+type: checkbox
+options:
+ - "Visual and mechanical inspection including anchorage, nameplate, clearances, and filler plates"
+ - "Bolted connection torque verification against the manufacturer's values, with the applied values recorded"
+ - "Insulation resistance of each phase bus and the neutral bus, phase-to-phase and phase-to-ground"
+ - "Contact resistance of the main bus joints and the line terminations"
+ - "Operation of every device through one open and close cycle"
+ - "Ground-fault protection of equipment performance test by primary current injection"
+ - "Trip unit settings verification against the coordination study"
+ - "Shunt trip and accessory operation from the initiating device"
+ - "Neutral-to-ground separation verification on every panelboard that is not service equipment"
+ - "Branch circuit continuity and phase assignment against the record panel schedule"
+default:
+ - "Visual and mechanical inspection including anchorage, nameplate, clearances, and filler plates"
+ - "Bolted connection torque verification against the manufacturer's values, with the applied values recorded"
+ - "Insulation resistance of each phase bus and the neutral bus, phase-to-phase and phase-to-ground"
+ - "Operation of every device through one open and close cycle"
+ - "Neutral-to-ground separation verification on every panelboard that is not service equipment"
+ - "Branch circuit continuity and phase assignment against the record panel schedule"
+```
+
+### Insulation resistance shall be measured for one minute at 500 V DC on a system rated 250 V and below and at 1000 V DC on a system rated above 250 V, and a reading below the minimum ANSI/NETA ATS states for the voltage class shall be investigated before the panelboard is energized.
+
+### A panelboard that fails a field acceptance test shall not be energized, the Contractor shall report the failure to the Engineer of Record within one working day with the measured values, and the cost of the correction and of every repeated test shall be borne by the Contractor.
+
+### Infrared thermographic inspection shall be as indicated in the datasheet.
+
+```datasheet
+label: Infrared Thermographic Inspection
+type: select
+options:
+ - "Not required"
+ - "One inspection within 90 days of energization"
+ - "One inspection within 90 days of energization and a second at eleven months"
+```
+
+### Where infrared inspection is indicated, it shall be performed with the panelboard carrying not less than 40% of its rated load on each scanned connection, and every connection showing a rise of more than 10 °C above its neighbors shall be reported and corrected.
+
+### A second inspection near the end of the first year finds the termination that loosened through the first full cycle of seasonal load, which the first inspection cannot see; it costs a second visit under load and a warranty claim filed before the warranty ends. {note}
+
+# Installation {toc}
+
+## Location and Working Space {toc}
+
+### The panelboard shall be installed at the location and in the orientation indicated on [[drawing: the electrical plans]], and its room shall satisfy [[sync/electrical-rooms]] where it is installed in an electrical room.
+
+### Working space in front of the panelboard shall comply with NFPA 70 110.26 for the system voltage and the condition of the space, and the door swing shall not reduce that space.
+
+### The dedicated electrical space above the panelboard required by NFPA 70 110.26(E) shall be kept clear of piping, ductwork, and equipment not associated with the electrical installation.
+
+### Working space shall not be used for storage at any time.
+
+### A panelboard shall not be installed in a clothes closet, in a bathroom of a dwelling unit, dormitory, or guest room, or over the steps of a stairway, in accordance with NFPA 70 240.24(D), (E), and (F).
+
+### A floor-standing panelboard shall be set on a concrete housekeeping pad constructed under [[sync/concrete-pads]], extending not less than 3 in. beyond the cabinet on every side and not less than 4 in. above the finished floor indoors or 6 in. above finished grade outdoors, and shall be anchored as indicated on [[drawing: the seismic anchorage details]].
+
+### Where seismic certification is required, the anchorage shall be that on which the certification depends, and a substitute anchor shall not be used without the manufacturer's written confirmation that the certification remains valid.
+
+## Mounting Height {toc}
+
+### The height from the finished floor to the top of a wall-mounted panelboard shall be as indicated in the datasheet.
+
+```datasheet
+label: Top-of-Panelboard Mounting Height
+type: range
+unit: in.
+drawing_ref: "the electrical details"
+options:
+ min: 48
+ max: 78
+ step: 6
+```
+
+### Where several panelboards stand in a row, their tops shall align unless the installation conditions require otherwise.
+
+### No device handle in the panelboard shall be installed with the center of its grip more than 6 ft 7 in. above the floor or working platform, in accordance with NFPA 70 240.24(A).
+
+### The handle height limit is a reach requirement rather than a mounting convention: a tall panelboard set to a comfortable top height can still put its uppermost handle past the limit, which is why the handle height is verified separately from the mounting height. {note}
+
+### A wall-mounted panelboard shall be anchored to the structure at not fewer than four points with fasteners engaging studs, masonry anchors, or structural backing, and a flush-mounted cabinet shall be secured to the rough opening framing so that the front sits flush with the finished wall.
+
+### A panelboard shall be installed plumb and level, and the interior shall be aligned in the cabinet so that the front trim fits without forcing.
+
+## Conductor Terminations {toc}
+
+### The main lugs and the feed-through lugs shall be of the type indicated in the datasheet.
+
+```datasheet
+label: Main and Feed-Through Lug Type
+type: radio
+options:
+ - "Mechanical set-screw lugs"
+ - "Compression lugs"
+default: manufacturer
+```
+
+### The manufacturer shall state the lug type furnished in the product data.
+
+### Mechanical lugs accept a range of conductor sizes and are the lugs the panelboard ships with; compression lugs are crimped to one conductor size with a tool matched to the lug, hold their pressure without re-torquing, and are used where the Owner's practice or the conductor material calls for them. {note}
+
+### Every lug shall be listed for the conductor material and size terminated in it, shall be rated for 75 °C conductors, and where aluminum conductors are terminated shall be listed for aluminum and the conductor prepared as the lug listing requires.
+
+### Every conductor termination shall be torqued to the device manufacturer's published value with a calibrated torque tool, and the values applied shall be recorded in the field test report.
+
+### A terminal shall carry one conductor unless the terminal is listed for more than one.
+
+### Conductors within the cabinet shall be trained and bundled so that each circuit can be identified and reached without disturbing its neighbors, shall not cross the bus, and shall not rest on a device.
+
+### Conductor selection and installation shall comply with [[sync/conductors-and-cables]], and raceways shall comply with [[sync/raceways-and-conduit]].
+
+## Circuit Balancing {toc}
+
+### Branch circuits shall be assigned across the phases so that, at the connected load used for the panel schedule, the load on any phase does not deviate from the average phase load by more than the tolerance indicated in the datasheet.
+
+```datasheet
+label: Maximum Phase Load Imbalance
+type: range
+unit: '%'
+options:
+ min: 5
+ max: 25
+ step: 5
+```
+
+### Where a tolerance is not selected in the datasheet, or where the tolerance cannot be met because of the fixed characteristics of the connected equipment, the Engineer of Record shall determine the acceptable phase assignment.
+
+### An unbalanced panelboard drives neutral current, unequal voltage drop between phases, and heating in the transformer and the feeder ahead of it; balancing costs nothing at the panel-schedule stage and is expensive to correct after the circuits are pulled. {note}
+
+### The final phase assignment of every branch circuit shall be recorded on the record panel schedule.
+
+# Delivery, Storage, and Handling {toc}
+
+## Each panelboard shall be delivered in the manufacturer's packaging with the listing marks and the nameplate intact, and shall be inspected for shipping damage at receipt.
+
+## Panelboards shall be stored indoors in a clean, dry space where the temperature is held above the dew point, and where indoor storage is not available they shall be stored under cover on pallets, off the ground, and protected from condensation, precipitation, dust, and physical damage.
+
+## Where a panelboard will stand more than 30 days in an unconditioned space before energization, its space heater, where furnished, shall be energized from a temporary source, or the cabinet shall otherwise be protected from condensation.
+
+## The interior shall remain in its packaging or covered until the branch circuit conductors are pulled, so that construction dust does not settle on the bus and the device terminals.
+
+## A panelboard damaged or wetted in transit, in storage, or in handling shall be repaired or replaced as the manufacturer directs and as the Engineer of Record accepts in writing.
+
+# Warranty {toc}
+
+## The manufacturer shall warrant each panelboard, its bus, and every factory-installed device against defects in materials and workmanship for the period indicated in the datasheet.
+
+```datasheet
+label: Manufacturer's Warranty Period
+type: range
+unit: years
+options:
+ min: 1
+ max: 5
+ setpoints: [1, 2, 3, 5]
+```
+
+## Where a warranty period is not selected in the datasheet, the manufacturer's standard warranty shall apply, and its term shall be stated in the product data.
+
+## The warranty period shall commence on the date indicated in the datasheet.
+
+```datasheet
+label: Warranty Commencement
+type: select
+options:
+ - "Date of substantial completion"
+ - "Date of energization"
+ - "Date of shipment"
+```
+
+## Warranty commencement at shipment is the manufacturer's usual term, and it consumes the warranty during storage and construction; commencement at energization or substantial completion moves the coverage to the period the Owner is operating the equipment, and the manufacturer prices the added months into the panelboard. {note}
+
+## The warranty coverage scope shall be as indicated in the datasheet.
+
+```datasheet
+label: Warranty Coverage Scope
+type: radio
+options:
+ - "Parts only"
+ - "Parts and labor"
+```
+
+## The Contractor shall warrant the installation, including every termination, the anchorage, and the field-installed accessories, for the project warranty period.
+
+## A device or interior replaced under warranty shall be warranted for the remainder of the original period or for one year from the date of replacement, whichever ends later, and the replacement shall not reduce the coverage of any other device in the panelboard.
+
+# Spare Parts {toc}
+
+## The Contractor shall deliver the spare parts indicated in the datasheet to the Owner before the panelboards are accepted, and shall obtain a signed receipt for them.
+
+```datasheet
+label: Spare Parts to Be Furnished
+type: checkbox
+options:
+ - "Two spare single-pole breakers of each trip rating installed"
+ - "One spare multi-pole breaker of each pole count and trip rating installed"
+ - "One spare ground-fault or arc-fault breaker of each type installed"
+ - "One set of filler plates for every space position on the project"
+ - "One set of fuses of each type and rating installed"
+default:
+ - "One set of filler plates for every space position on the project"
+```
+
+## Spare devices shall be identical to and interchangeable with the installed devices, shall be delivered in their original packaging, and shall be labeled with the panelboard designation or the device rating they serve.
+
+## Spare devices shall be stored in a labeled container in the electrical room, and shall not be stored inside an operating panelboard.