Panelboards

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SynC Standards Team — Specifier (Platform Standards) ✓ OfficialDiscloses employment SynC (SynC Platform Team)

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Showing changes from Rev 2 to Rev 3 in Panelboards.

−---

−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 buildings - lighting-and-appliance

− and power distribution panelboards installed as sub-distribution points fed from

− switchboards, switchgear, or larger panelboards. Covers main-breaker (MCB) and

− main-lug-only (MLO) configurations, surface- and flush-mounted enclosures, and

− the branch-circuit overcurrent devices housed within.

− Not intended for: residential-grade low-voltage load centers (use

− sync/low-voltage-panelboards); enclosed safety switches and fused disconnects

− (use sync/enclosed-switches-and-disconnects); grounding electrode conductors and

− bonding within the panelboard (use sync/grounding-and-bonding); feeder and branch

− conductors entering and leaving the panelboard (use sync/conductors-and-cables);

− switchboards, switchgear, and multi-section lineups; and medium-voltage (above

− 1000 V) distribution panels.

−---

−

−# Scope {toc}

−

−## This standard covers dead-front panelboards rated 1000 V or less for use in commercial, institutional, and light-to-medium industrial buildings. {note}

−

−## It applies to lighting-and-appliance panelboards and power distribution panelboards installed as sub-distribution points fed from switchboards, switchgear, or larger panelboards. {note}

−

−## The scope includes main-breaker and main-lug-only configurations, surface- and flush-mounted enclosures, and the branch-circuit overcurrent devices housed within the panelboard. {note}

−

−## A panelboard is a single-panel or group-of-panels assembly designed for installation in a cabinet or cutout box, accessible only from the front, and includes buses and overcurrent devices for the control of light, heat, or power circuits. The dead-front construction places no energized parts on the operating face once the trim is installed. {note}

−

−## The following are excluded from this standard. {note}

−

−### Residential-grade low-voltage load centers (typically 200 A or less, tested to the consumer-product provisions of UL 67) are covered by [[sync/low-voltage-panelboards]]. {note}

−

−### Enclosed safety switches, fused disconnects, and non-automatic disconnecting means are covered by [[sync/enclosed-switches-and-disconnects]]. {note}

−

−### Grounding electrode conductors, bonding jumpers, and equipment grounding terminations within the panelboard are covered by [[sync/grounding-and-bonding]]. {note}

−

−### Feeder and branch conductors entering and leaving the panelboard are covered by [[sync/conductors-and-cables]]. {note}

−

−### Switchboards, switchgear, and multi-section distribution lineups (typically mains above 1600 A) are outside the scope of UL 67 and NEMA PB 1 and are specified under a separate switchboard standard. {note}

−

−### Medium-voltage distribution panels rated above 1000 V are outside the scope of UL 67 entirely. {note}

−

−# 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 referenced standards conflict, the more stringent requirement shall govern unless the Engineer of Record directs otherwise in writing.

−

−## The adoption of the National Electrical Code and its effective edition varies by jurisdiction; the edition enforced by the Authority Having Jurisdiction shall be verified before fabrication. {note}

−

−| Standard | Title |

−|----------|-------|

−| UL 67 | Panelboards |

−| NEMA PB 1 | Panelboards |

−| ANSI/NEMA PB 1.1 | General Instructions for Proper Installation, Operation and Maintenance of Panelboards Rated 1000 V or Less |

−| NFPA 70 (NEC), Article 408 | National Electrical Code - Switchboards, Switchgear, and Panelboards |

−| NFPA 70 (NEC), Article 240 | National Electrical Code - Overcurrent Protection |

−| NFPA 70 (NEC), Article 230 | National Electrical Code - Services |

−| NFPA 70 (NEC), Article 285 | National Electrical Code - Surge-Protective Devices |

−| NFPA 70 (NEC), Article 220 | National Electrical Code - Branch-Circuit, Feeder, and Service Load Calculations |

−| NFPA 70 (NEC), Article 110 | National Electrical Code - Requirements for Electrical Installations |

−| NFPA 70 (NEC), Article 700 | National Electrical Code - Emergency Systems |

−| IEEE 1584 | Guide for Performing Arc-Flash Hazard Calculations |

−| UL 489 | Molded-Case Circuit Breakers, Molded-Case Switches, and Circuit-Breaker Enclosures |

−

−# Submittals {toc}

−

−## Action Submittals {toc}

−

−### The Contractor shall submit the following action submittals for review and approval before fabrication:

−

−- Product data for each panelboard type, including ratings, dimensions, enclosure type, and bus material.

−- Shop drawings showing panelboard schedule, circuit arrangement, ampere ratings, and interrupting ratings.

−- Panelboard schedules listing each branch circuit, its overcurrent device rating, number of poles, and connected load.

−- Dimensioned enclosure drawings showing gutter space, wiring space, and conduit entry locations.

−- Short-circuit current rating (SCCR) of each panelboard with supporting documentation.

−- Wiring diagrams differentiating factory-installed and field-installed wiring.

−

−```datasheet

−label: Action submittals required

−type: checkbox

−options:

− - Product data

− - Shop drawings

− - Panelboard schedules

− - Enclosure dimension drawings

− - SCCR documentation

− - Wiring diagrams

−```

−

−### Where selective coordination is required for an emergency, legally required standby, or critical operations power system, the Contractor shall submit a coordination study sealed by a registered professional engineer.

−

−### Where an arc-flash study is required by the Owner or the Authority Having Jurisdiction, the Contractor shall submit incident-energy calculations performed in accordance with IEEE 1584.

−

−## Informational Submittals {toc}

−

−### The Contractor shall submit the following informational submittals:

−

−- Manufacturer's product certifications confirming UL 67 listing.

−- Field quality-control test reports, including torque verification records.

−- Source quality-control reports for factory-installed surge protective devices.

−

−```datasheet

−label: Informational submittals required

−type: checkbox

−options:

− - UL 67 listing certification

− - Field test reports

− - Torque verification records

− - SPD source test reports

−```

−

−## Closeout Submittals {toc}

−

−### The Contractor shall submit the following closeout submittals before final acceptance:

−

−- Operation and maintenance manuals prepared in accordance with ANSI/NEMA PB 1.1.

−- As-built panelboard schedules reflecting final installed circuit assignments.

−- Final laminated or typed circuit directory installed in each panelboard.

−- Warranty documentation.

−

−```datasheet

−label: Closeout submittals required

−type: checkbox

−options:

− - Operation and maintenance manuals

− - As-built panelboard schedules

− - Final circuit directory

− - Warranty documentation

−```

−

−# Quality Assurance {toc}

−

−## Each panelboard shall be listed and labeled to UL 67 by a Nationally Recognized Testing Laboratory.

−

−## Each branch-circuit and main overcurrent device shall be listed to UL 489 where it is a molded-case circuit breaker.

−

−## Panelboards shall be the product of a single manufacturer for a given project to maintain interchangeability of breakers and trim. {note}

−

−### Using a single manufacturer across a project allows spare breakers and replacement parts to be stocked once and installed in any panel, and avoids field confusion between visually similar but non-interchangeable breaker lines. {note}

−

−## The manufacturer shall have produced panelboards of the type specified for a minimum of five years.

−

−## Field modifications that alter the listing, such as drilling additional knockouts in a NEMA 3R enclosure or adding non-listed components, shall void the listing and are prohibited.

−

−# Ratings {toc}

−

−## Panelboard Class {toc}

−

−### A lighting-and-appliance panelboard is one having more than 10 percent of its overcurrent devices rated 30 A or less for which neutral connections are provided; a power distribution panelboard is any panelboard that is not a lighting-and-appliance panelboard. {note}

−

−### The classification governs the maximum overcurrent device count and main-device rules under NEC Article 408; misclassifying a panel leads to upsized or non-code-compliant designs and is a frequent code-interpretation error. {note}

−

−### Each panelboard shall be classified as a lighting-and-appliance panelboard or a power distribution panelboard.

−

−```datasheet

−label: Panelboard class

−type: radio

−options:

− - Lighting-and-appliance

− - Power distribution

−default: Lighting-and-appliance

−```

−

−### A lighting-and-appliance branch-circuit panelboard shall not contain more than 42 overcurrent devices, excluding the main, in a single cabinet or cutout box.

−

−## Voltage and Phase {toc}

−

−### The system voltage, phase, and number of wires for each panelboard are determined by the upstream distribution design and shown on the drawings. {note}

−

−### Each panelboard shall be rated for the system voltage and phase configuration indicated.

−

−```datasheet

−label: System voltage and phase

−type: radio

−options:

− - 120/240 V 1Φ 3-wire

− - 120/208 V 3Φ 4-wire

− - 277/480 V 3Φ 4-wire

−default: 120/208 V 3Φ 4-wire

−```

−

−### The panelboard voltage rating shall equal or exceed the nominal system voltage at the point of installation.

−

−## Main Device {toc}

−

−### A main-breaker (MCB) panelboard includes an integral overcurrent device on the line side of the branch buses; a main-lug-only (MLO) panelboard terminates the feeder directly on the bus with no integral main device. {note}

−

−### A main lug only panelboard relies on an upstream overcurrent device for its main protection; specifying MLO where NEC 225.32 or 230.70 requires a disconnecting means at the panel results in field relabeling or replacement. {note}

−

−### Each panelboard shall be furnished as a main-breaker or main-lug-only type as indicated.

−

−```datasheet

−label: Main device type

−type: radio

−options:

− - Main circuit breaker (MCB)

− - Main lug only (MLO)

−default: Main circuit breaker (MCB)

−```

−

−### A lighting-and-appliance branch-circuit panelboard shall be provided with individual protection on the supply side by an overcurrent device rated not greater than the panelboard rating, unless protection is otherwise provided in accordance with NEC 408.36 exceptions.

−

−### The main device ampere rating shall be coordinated with the calculated load per NEC Article 220 and with the rating of the bus.

−

−```datasheet

−label: Main device ampere rating

−type: select

−unit: A

−options:

− - 100

− - 125

− - 150

− - 200

− - 225

− - 250

− - 400

− - 600

− - 800

− - 1000

− - 1200

−default: 225

−drawing_ref: panelboard schedule

−```

−

−## Bus Rating {toc}

−

−### The main bus continuous current rating shall be not less than the main device rating and not less than the calculated continuous load.

−

−### The bus bracing shall withstand the mechanical stresses produced by the short-circuit current rating of the panelboard.

−

−```datasheet

−label: Main bus continuous rating

−type: select

−unit: A

−options:

− - 100

− - 125

− - 150

− - 200

− - 225

− - 250

− - 400

− - 600

− - 800

− - 1000

− - 1200

−default: 225

−drawing_ref: panelboard schedule

−```

−

−## Short-Circuit Current Rating {toc}

−

−### The short-circuit current rating (SCCR) is the maximum prospective fault current the panelboard can safely interrupt or withstand; it must equal or exceed the available fault current at the point of installation under NEC 110.10. {note}

−

−### The available fault current depends on the upstream transformer, utility contribution, and conductor impedance, and must be stated on the drawings; specifying an SCCR without providing the available fault current forces the Contractor to submit an RFI. {note}

−

−### The panelboard short-circuit current rating shall equal or exceed the available fault current at the line terminals.

−

−### The available fault current at the panelboard line terminals shall be as indicated [[drawing: one-line diagram fault-current notation]].

−

−```datasheet

−label: Minimum panelboard SCCR

−type: select

−unit: kA

−options:

− - 10

− - 14

− - 22

− - 25

− - 35

− - 42

− - 65

− - 100

−default: 22

−```

−

−### A series-rated combination shall be applied only where the combination is tested and listed, and the panelboard shall be field-marked to indicate the series combination rating and the devices involved.

−

−# Overcurrent Devices {toc}

−

−## Branch Breaker Mounting {toc}

−

−### Bolt-on breakers are secured to the bus with a threaded fastener; plug-in breakers engage the bus by a stab connection and are retained by spring tension. {note}

−

−### Some Owner standards and Authorities Having Jurisdiction require bolt-on breakers for reliability in commercial applications; specifying a panel that accepts only plug-in breakers in that case will generate substitution requests. {note}

−

−### Branch-circuit breakers shall be of the mounting type indicated for the panelboard.

−

−```datasheet

−label: Branch breaker mounting

−type: radio

−options:

− - Bolt-on

− - Plug-in

−default: Bolt-on

−```

−

−## Branch Breaker Type {toc}

−

−### Branch-circuit overcurrent devices shall be thermal-magnetic molded-case circuit breakers unless a fused branch device is indicated.

−

−### Branch breakers serving circuits required by NEC to have arc-fault or ground-fault protection shall be of the corresponding type.

−

−```datasheet

−label: Branch breaker protection type

−type: select

−options:

− - Standard thermal-magnetic

− - Ground-fault circuit interrupter (GFCI)

− - Arc-fault circuit interrupter (AFCI)

− - Combination AFCI/GFCI

−default: Standard thermal-magnetic

−```

−

−### Tandem (twin) breakers shall be used only in panelboard positions specifically listed to accept them and only where permitted by NEC 408.54.

−

−### Each branch breaker shall have an interrupting rating not less than the available fault current at its line terminals.

−

−## Spaces and Spares {toc}

−

−### The number of circuit spaces (poles) shall be coordinated with the distribution design; specifying a panel smaller than the required circuit count forces change orders or additional panels. {note}

−

−### Each panelboard shall provide the number of circuit positions indicated.

−

−```datasheet

−label: Number of circuit positions (poles)

−type: select

−options:

− - 12

− - 18

− - 24

− - 30

− - 42

− - 54

− - 60

− - 72

−default: 42

−drawing_ref: panelboard schedule

−```

−

−### Each panelboard shall be furnished with the indicated number of spare overcurrent devices, installed and connected to spare bus positions.

−

−```datasheet

−label: Installed spare breakers

−type: range

−unit: count

−min: 0

−max: 12

−step: 1

−default: 2

−```

−

−### Each panelboard shall retain a minimum percentage of its positions as unequipped spaces for future circuits.

−

−```datasheet

−label: Minimum spare capacity (unequipped spaces)

−type: range

−unit: '%'

−min: 0

−max: 30

−step: 5

−default: 20

−```

−

−# Construction {toc}

−

−## Bus Material {toc}

−

−### Copper bus has lower resistivity and is dimensionally stable at terminations; aluminum bus is lighter and lower cost but requires controlled torque and anti-oxidant compound to maintain a stable connection over time. {note}

−

−### Aluminum connections that are not properly torqued and treated loosen over time and develop high-resistance hot spots; specifying aluminum bus without stating these requirements is a recurring source of failures. {note}

−

−### Panelboard buses shall be of the material indicated.

−

−```datasheet

−label: Bus material

−type: radio

−options:

− - Copper

− - Aluminum

−default: Copper

−```

−

−### Where aluminum bus or aluminum lug connections are used, terminations shall be made with the manufacturer's specified torque value and treated with a listed anti-oxidant compound.

−

−### Bus bars shall be of uniform cross-section throughout the length of the panelboard for the full ampere rating.

−

−## Neutral and Ground Bus {toc}

−

−### Each panelboard supplying a circuit requiring a neutral shall include a full-capacity insulated neutral bus rated for the same current as the phase bus.

−

−### Each panelboard shall include an equipment grounding bus bonded to the enclosure.

−

−### An isolated (insulated) equipment grounding bus shall be provided only where indicated for sensitive-equipment branch circuits.

−

−```datasheet

−label: Equipment grounding bus

−type: radio

−options:

− - Standard bonded ground bus

− - Standard plus isolated ground bus

−default: Standard bonded ground bus

−```

−

−## Enclosure {toc}

−

−### The enclosure NEMA type shall be selected for the environment of the installation; an indoor type installed outdoors or in a wash-down area will admit water or dust and corrode. {note}

−

−### Each panelboard enclosure shall be rated for the indicated NEMA type.

−

−```datasheet

−label: Enclosure NEMA type

−type: radio

−options:

− - NEMA 1 (indoor, general purpose)

− - NEMA 3R (outdoor, rainproof)

− - NEMA 4X (corrosion-resistant, wash-down)

− - NEMA 12 (industrial, dust-tight)

−default: NEMA 1 (indoor, general purpose)

−```

−

−### Enclosure boxes and trims shall be fabricated from sheet steel finished with a corrosion-resistant coating, or from stainless steel where a NEMA 4X corrosion-resistant rating is indicated.

−

−### The enclosure shall provide gutter and wiring space not less than the minimum required by NEC Article 408 and UL 67 for the conductors installed.

−

−## Mounting {toc}

−

−### A surface-mounted panel is fastened to the wall face; a flush-mounted panel is recessed into the wall with only its trim exposed, and requires the wall depth and conduit stub-outs to be coordinated before rough-in. {note}

−

−### Each panelboard shall be furnished for the indicated mounting method.

−

−```datasheet

−label: Mounting method

−type: radio

−options:

− - Surface

− - Flush

− - Semi-flush

−default: Surface

−```

−

−### Flush-mounted panelboards shall be furnished with empty conduit stub-outs from the gutter to an accessible location above an accessible ceiling for future circuit extension.

−

−```datasheet

−label: Flush-mount spare conduit stub-outs

−type: range

−unit: count

−min: 0

−max: 6

−step: 1

−default: 2

−```

−

−## Trim and Door {toc}

−

−### The front trim shall be of the dead-front type, concealing all energized parts and breaker line terminals when the door is open.

−

−### The door shall be furnished with a flush latch and a key lock, and all panelboards on a project shall be keyed alike.

−

−### A directory cardholder with a transparent cover shall be mounted on the inside face of the door.

−

−# Service-Entrance and Special Provisions {toc}

−

−## Service-Entrance Rating {toc}

−

−### Standard panelboards lack the main bonding jumper, neutral-to-ground bond, and service markings required of service equipment; a panel used as the first means of disconnect after the meter must be specified as service-entrance rated. {note}

−

−### Where the panelboard serves as service equipment, it shall be listed and labeled as suitable for use as service equipment.

−

−```datasheet

−label: Service-entrance rated

−type: radio

−options:

− - 'No'

− - 'Yes'

−default: 'No'

−```

−

−### Where the panelboard is service equipment, a factory-installed main bonding jumper connecting the neutral bus to the enclosure shall be provided.

−

−## Surge Protective Device {toc}

−

−### The NEC requires surge protective devices on service-entrance equipment for most commercial buildings, and carrying surge protection downstream to sub-panels serving sensitive equipment areas protects those loads from internally generated transients. {note}

−

−### A factory-installed surge protective device offers a lower let-through voltage and a shorter lead length than a field-installed unit, but commits the panel to a single SPD model; a field-installed unit is more flexible. {note}

−

−### A surge protective device shall be provided where indicated, either factory-installed within the panelboard or field-installed at the panelboard.

−

−```datasheet

−label: Surge protective device

−type: select

−options:

− - None

− - Factory-installed integral SPD

− - Field-installed SPD

−default: None

−```

−

−### The surge protective device, where provided, shall be a Type 1 or Type 2 device as required by its point of connection under NEC Article 285.

−

−## Selective Coordination {toc}

−

−### Selective coordination requires that only the overcurrent device nearest a fault opens, leaving upstream devices closed; the NEC mandates it for emergency, legally required standby, and critical operations power systems. {note}

−

−### Selective coordination must be demonstrated by a study comparing actual breaker time-current curves; it cannot be assumed from device ratings alone. {note}

−

−### Where the panelboard serves an emergency, legally required standby, or critical operations power system, the overcurrent devices shall be selectively coordinated with all upstream and downstream devices.

−

−## Metering {toc}

−

−### Where indicated, the panelboard shall include integral metering provisions, current transformers, or a meter socket within or adjacent to the enclosure.

−

−```datasheet

−label: Integral metering provisions

−type: select

−options:

− - None

− - Current transformer compartment

− - Integral revenue meter socket

− - Integral power/energy meter

−default: None

−```

−

−# Identification {toc}

−

−## A permanent nameplate shall be affixed to each panelboard identifying its designation, voltage, phase, main device rating, and source.

−

−```datasheet

−label: Nameplate engraving

−type: text

−placeholder: 'Panel designation, voltage, phase, main rating, fed-from source'

−```

−

−## Each panelboard shall be field-marked with the maximum available fault current and the date the calculation was performed, in accordance with NEC 110.24.

−

−## A series-combination-rated panelboard shall be field-marked to identify the series rating and the devices that establish it.

−

−## A typed or computer-generated circuit directory accurately identifying the load served by each circuit shall be installed in each panelboard at closeout, in accordance with NEC 408.4. {note}

−

−### The NEC requires permanent, legible circuit identification, yet specifications often omit the requirement for the final laminated schedule, leaving hand-written directories that become illegible. {note}

−

−### A typed or computer-generated circuit directory shall be installed in the directory cardholder of each panelboard at closeout.

−

−# Environmental and Service Conditions {toc}

−

−## Panelboards shall be suitable for continuous operation at the ambient temperature of the installed location without derating below the rating indicated. {note}

−

−### Each panelboard shall be rated for service at the indicated maximum ambient temperature.

−

−```datasheet

−label: Maximum ambient temperature

−type: range

−unit: °C

−min: 25

−max: 50

−step: 5

−default: 40

−```

−

−### Each panelboard installed above an indicated elevation shall be derated in accordance with the manufacturer's altitude correction data.

−

−```datasheet

−label: Installation altitude

−type: range

−unit: m

−min: 0

−max: 3000

−step: 500

−default: 0

−```

−

−# Testing {toc}

−

−## Source Quality Control {toc}

−

−### Each panelboard shall be production tested at the factory in accordance with UL 67, including a dielectric withstand test.

−

−### Each factory-installed surge protective device shall be functionally tested at the factory before shipment.

−

−## Field Quality Control {toc}

−

−### After installation, each panelboard shall be inspected for tightness of all bus and terminal connections.

−

−### Each accessible bolted bus and lug connection shall be torqued to the manufacturer's published value and the value shall be recorded.

−

−### Each branch and main overcurrent device shall be exercised manually from off to on to off before energization.

−

−### Insulation-resistance testing shall be performed phase-to-phase and phase-to-ground before energization where required by the Owner.

−

−```datasheet

−label: Field tests required

−type: checkbox

−options:

− - Connection tightness inspection

− - Torque verification with recorded values

− - Manual operation of all devices

− - Insulation-resistance test

−```

−

−# Installation {toc}

−

−## Working Clearances {toc}

−

−### The dedicated electrical space above a panelboard - extending from the floor to a height of 1.8 m above the equipment or to the structural ceiling, whichever is lower - must be kept clear of piping, ducts, and other systems not serving the equipment under NEC 110.26(F). {note}

−

−### Ceiling soffits, ductwork, and piping routed through the dedicated space above a panel are a frequent source of field conflicts and RFIs when not coordinated on the architectural drawings during design. {note}

−

−### Each panelboard shall be installed with the working clearances required by NEC 110.26 maintained clear of obstruction.

−

−### The dedicated electrical space above each panelboard shall be kept clear of foreign systems in accordance with NEC 110.26(F).

−

−### Panelboards shall not be installed in the dedicated space of, or within the working clearance of, other equipment unless the arrangement is shown on the drawings [[drawing: electrical room equipment layout]].

−

−## Mounting Height {toc}

−

−### Each panelboard shall be mounted so that the highest operating handle does not exceed the maximum reach height permitted by NEC 240.24.

−

−```datasheet

−label: Top operating handle height above finished floor

−type: range

−unit: m

−min: 1.5

−max: 2.0

−step: 0.1

−default: 1.8

−```

−

−### Panelboards shall be mounted plumb and securely fastened to the building structure, independent of the conduit entering the enclosure.

−

−## Connections {toc}

−

−### Feeder and branch conductors shall be terminated at the panelboard lugs with the conductor material for which the lug is listed.

−

−### Aluminum conductor terminations shall be treated with a listed anti-oxidant compound and torqued to the manufacturer's value.

−

−### Circuits shall be balanced across the phases so that the load on any phase does not deviate from the average phase load by more than the indicated tolerance.

−

−```datasheet

−label: Maximum phase load imbalance

−type: range

−unit: '%'

−min: 5

−max: 20

−step: 5

−default: 10

−```

−

−# Delivery, Storage, and Handling {toc}

−

−## Panelboards shall be delivered to the site in the manufacturer's original packaging with the listing label and ratings intact.

−

−## Panelboards shall be stored indoors in a clean, dry space and protected from construction dust, moisture, and physical damage until installation.

−

−## Panelboards shall be kept covered and energized with space heaters where provided, or otherwise protected from condensation, during prolonged storage.

−

−# Warranty {toc}

−

−## The manufacturer shall warrant each panelboard and its overcurrent devices against defects in materials and workmanship for the indicated period from the date of substantial completion.

−

−```datasheet

−label: Manufacturer warranty period

−type: range

−unit: year

−min: 1

−max: 5

−step: 1

−default: 1

−```

−

−## The warranty shall cover repair or replacement of defective components, including labor for replacement of factory-installed devices.

−

−# Spare Parts {toc}

−

−## The Contractor shall furnish spare branch-circuit breakers of each frame and pole configuration used, in the indicated quantity, delivered to the Owner at closeout.

−

−```datasheet

−label: Spare branch breakers per configuration

−type: range

−unit: count

−min: 0

−max: 6

−step: 1

−default: 2

−```

−

−## The Contractor shall furnish spare directory cards and blank trim fillers for each panelboard type.

+---

+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}

+|-----------------|-----------------------------------|--------------------------------------|-------------------------------------------------------------------|

+| 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.

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