Low Voltage Switchgear

Revision 2 · SynC Standards Team — Specifier, SynC (SynC Platform Team / Platform Standards) ✓ Official · Jun 4, 2026 +855 −685

Granular element model: citable clauses + {note} rationale

Showing changes from Rev 1 to Rev 2 in Low Voltage Switchgear.

−---

−title: Low Voltage Switchgear

−category: Power Distribution

−toc_depth: 3

−description: >

− When to use: Metal-enclosed, low voltage power circuit breaker switchgear rated 600V and below for commercial, institutional, and industrial facilities. Covers indoor and outdoor configurations with drawout power circuit breakers. Not intended for: Panelboards (see [[sync/low-voltage-panelboards]]), switchboards (see [[sync/low-voltage-switchboards]]), motor control centers (see [[sync/motor-control-centers]]), or medium voltage switchgear above 600V (see [[sync/medium-voltage-switchgear]]).

−---

−

−# Scope

−

−This specification covers metal-enclosed, low voltage power circuit breaker switchgear assemblies rated 600V and below. Equipment shall comply with UL 1558 and IEEE C37.20.1 and shall be listed and labeled by a Nationally Recognized Testing Laboratory (NRTL).

−

−Switchgear covered by this standard utilizes individually mounted drawout power circuit breakers as the primary switching and protective devices. For applications using molded case or insulated case breakers in a non-drawout configuration, see [[sync/low-voltage-switchboards]].

−

−For medium voltage switchgear rated above 600V, see [[sync/medium-voltage-switchgear]]. Grounding and bonding per [[sync/grounding-and-bonding]].

−

−# Referenced Standards

−

−Equipment and installation shall comply with the latest edition of the following. Where conflicts exist between referenced standards, the more stringent requirement shall govern unless otherwise directed by the Engineer of Record.

−

−| Standard | Title |

−|----------|-------|

−| UL 1558 | Metal-Enclosed Low-Voltage Power Circuit Breaker Switchgear |

−| IEEE C37.20.1 | Metal-Enclosed Low-Voltage Power Circuit Breaker Switchgear |

−| IEEE C37.13 | Low-Voltage AC Power Circuit Breakers Used in Enclosures |

−| IEEE C37.20.7 | Arc-Resistance Testing of Metal-Enclosed Switchgear |

−| IEEE C37.51 | Conformance Testing of Metal-Enclosed LV AC Power Circuit Breaker Switchgear |

−| IEEE C37.90 | Relays and Relay Systems Associated with Electric Power Apparatus |

−| IEEE C57.13 | Requirements for Instrument Transformers |

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

−| NFPA 70 | National Electrical Code |

−| NEMA ICS 6 | Industrial Control and Systems: Enclosures |

−| NETA ATS | Acceptance Testing Specifications for Electrical Power Equipment and Systems |

−| ASCE 7 | Minimum Design Loads and Associated Criteria for Buildings |

−| ASHRAE 90.1 | Energy Standard for Buildings (submetering requirements) |

−| ANSI/NEMA SG 3 | Low-Voltage Power Circuit Breakers |

−

−# Submittals

−

−## Action Submittals

−

−Contractor shall submit the following for review prior to fabrication:

−

−- Shop drawings showing front, side, and rear elevations with overall dimensions

−- Single line diagram indicating breaker frame sizes, trip ratings, and bus configuration

−- Bill of materials listing all major components

−- Breaker time-current coordination curves for all protective devices

−- Control schematic and wiring diagrams

−- Seismic certification documentation, where required

−

−```datasheet

−label: Submittal Documentation

−type: checkbox

−options:

− - "Shop drawings (front, side, rear elevations)"

− - "Single line diagram"

− - "Bill of materials"

− - "Time-current coordination curves"

− - "Control schematics and wiring diagrams"

− - "Seismic certification (IBC/ASCE 7)"

− - "Arc flash calculation input data"

− - "Catalog cut sheets for all protective devices"

−default: "Shop drawings (front, side, rear elevations)"

−```

−

−## Closeout Submittals

−

−Contractor shall provide at substantial completion:

−

−- Operation and maintenance manuals, bound with table of contents

−- As-built shop drawings reflecting field modifications

−- Factory and field test reports

−- Warranty documentation

−- Spare parts inventory with reorder information

−

−# Quality Assurance

−

−## Manufacturer Qualifications

−

−Switchgear shall be manufactured by a single company responsible for the assembly, bus, and all integral protective devices. The manufacturer shall have a minimum of five years documented experience producing UL 1558 listed switchgear and shall maintain an ISO 9001 certified quality management system.

−

−The manufacturer shall maintain a 24/7 service organization with factory-trained field representatives available within 24 hours of notification.

−

−## Source Limitations

−

−All switchgear sections, bus, circuit breakers, protective relays, and metering equipment shall be produced or furnished by the switchgear manufacturer as an integrated assembly. Third-party components assembled by others are not acceptable.

−

−## Testing Personnel Qualifications

−

−Acceptance testing shall be performed by a firm regularly engaged in testing electrical power equipment, employing technicians certified by NETA or equivalent. Testing personnel shall have a minimum of three years experience testing low voltage switchgear assemblies.

−

−# Environmental and Service Conditions

−

−Switchgear shall be suitable for continuous operation under the following ambient conditions. Where site conditions exceed these parameters, notify the manufacturer and derate equipment accordingly.

−

−```datasheet

−label: Ambient Temperature (Maximum)

−type: select

−unit: °C

−options:

− - "40°C (standard rating)"

− - "50°C (tropical rating)"

− - "55°C (desert/rooftop rating)"

−default: "40°C (standard rating)"

−```

−

−```datasheet

−label: Installation Altitude

−type: select

−options:

− - "Below 6,600 ft (2,000 m) - No derating"

− - "6,600 - 9,900 ft (2,000 - 3,000 m) - Derating required"

− - "Above 9,900 ft (3,000 m) - Consult manufacturer"

−default: "Below 6,600 ft (2,000 m) - No derating"

−```

−

−Equipment rated for standard conditions (40°C, below 6,600 ft) shall be derated per IEEE C37.20.1 when installed outside these parameters. The Engineer shall document derating calculations on the contract drawings.

−

−```datasheet

−label: Corrosion Severity

−type: select

−options:

− - "C2 - Low (indoor, climate-controlled)"

− - "C3 - Medium (indoor, unconditioned)"

− - "C4 - High (coastal, chemical exposure)"

− - "C5 - Very High (industrial, marine)"

−default: "C2 - Low (indoor, climate-controlled)"

−```

−

−For installations classified C4 or C5, bus bars shall be copper (tin or silver-plated), and enclosure paint systems shall provide enhanced corrosion protection per IEEE C57.12.29. See [[sync/electrical-rooms]] for room environmental classification requirements.

−

−## Seismic Requirements

−

−Where required by the applicable building code, switchgear shall be seismically certified by shake-table testing per ICC ES AC156 or by analysis per ASCE 7.

−

−```datasheet

−label: Seismic Certification

−type: select

−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: "Not required"

−```

−

−Seismic certification shall be by an independent third-party testing laboratory. Certification shall cover the complete assembly including all circuit breakers, bus, and ancillary components as installed. Certification of individual components in isolation is not acceptable.

−

−# Electrical Requirements

−

−## System Ratings

−

−```datasheet

−label: Service Entrance Equipment

−type: radio

−options:

− - "Yes - Main Service Entrance"

− - "No - Downstream Distribution"

−default: "No - Downstream Distribution"

−```

−

−Where switchgear serves as main service entrance equipment, it shall comply with NFPA 70 Article 230 including provisions for metering, service disconnect, and available fault current labeling. Coordinate metering requirements with the serving utility prior to submittal.

−

−```datasheet

−label: System Voltage

−type: select

−options:

− - "120/208V 3-Phase 4-Wire"

− - "277/480V 3-Phase 4-Wire"

− - "480V 3-Phase 3-Wire"

−default: "277/480V 3-Phase 4-Wire"

−```

−

−```datasheet

−label: System Frequency

−type: radio

−unit: Hz

−options:

− - "60 Hz"

− - "50 Hz"

−default: "60 Hz"

−```

−

−## Bus Rating

−

−Main bus continuous current rating shall be [[drawing: as indicated on the one-line diagram]]. Bus shall be braced for the available short-circuit current at the point of installation as determined by a short-circuit analysis per IEEE 551.

−

−```datasheet

−label: Main Bus Continuous Current

−type: range

−unit: A

−drawing_ref: true

−options:

− min: 800

− max: 5000

− setpoints: [800, 1200, 1600, 2000, 2500, 3000, 4000, 5000]

−default: 1600

−```

−

−```datasheet

−label: Short-Circuit Current Rating

−type: select

−unit: kAIC

−options:

− - "42 kAIC"

− - "65 kAIC"

− - "85 kAIC"

− - "100 kAIC"

− - "200 kAIC"

−default: "65 kAIC"

−```

−

−Short-circuit current rating shall equal or exceed the available fault current at the switchgear terminals. Verify available fault current with the utility provider and perform a short-circuit study per [[sync/short-circuit-study]] prior to equipment procurement.

−

−```datasheet

−label: Short-Time Withstand Rating

−type: select

−options:

− - "30-cycle (0.5 seconds)"

− - "15-cycle (0.25 seconds)"

−default: "30-cycle (0.5 seconds)"

−```

−

−## Neutral and Ground Bus

−

−```datasheet

−label: Neutral Bus Rating

−type: select

−options:

− - "Full rated (100% of main bus)"

− - "Reduced (50% of main bus)"

− - "Oversized (200% of main bus)"

− - "Not applicable (3-wire system)"

−default: "Full rated (100% of main bus)"

−```

−

−Oversized neutral bus is required where nonlinear loads exceed 30% of the total connected load to accommodate triplen harmonic currents. The Engineer shall evaluate harmonic loading per IEEE 519 when selecting neutral bus sizing.

−

−```datasheet

−label: Ground Bus

−type: radio

−options:

− - "Included - Full length of assembly"

− - "Not required"

−default: "Included - Full length of assembly"

−```

−

−Ground bus shall be bare copper, minimum 1/4 in. x 2 in. cross-section, extending the full length of the switchgear assembly. Ground bus shall be accessible without removing any covers or barriers required for safe operation.

−

−# Physical Construction

−

−## Enclosure

−

−Enclosure shall be fabricated from galvanized steel with a minimum thickness of 12 gauge (2.66 mm) for structural members and 14 gauge (1.90 mm) for covers and doors. All joints shall be continuously welded or bolted with gaskets as required for the specified NEMA rating.

−

−```datasheet

−label: Enclosure Rating

−type: select

−options:

− - "NEMA 1 - Indoor General Purpose"

− - "NEMA 3R - Outdoor Rainproof"

− - "NEMA 12 - Industrial (dust-tight)"

−default: "NEMA 1 - Indoor General Purpose"

−```

−

−For outdoor installations (NEMA 3R), enclosure shall include sun shields, rain hoods over ventilation openings, and condensation heaters in each section. Heater sizing shall be a minimum of 250W per vertical section. Heaters shall be thermostat controlled and wired to remain energized whenever the switchgear is de-energized.

−

−```datasheet

−label: Front Accessibility

−type: radio

−options:

− - "Front accessible only"

− - "Front and rear accessible"

−default: "Front accessible only"

−```

−

−Rear-accessible configurations require minimum 36 in. working clearance at rear per NFPA 70 Article 110.26. Rear compartments shall have individual hinged doors with padlockable latches.

−

−Switchgear overall dimensions and arrangement shall be [[drawing: per the equipment room layout drawings]].

−

−## Bus Bars

−

−```datasheet

−label: Bus Bar Material

−type: radio

−options:

− - "Copper"

− - "Copper (tin-plated)"

− - "Copper (silver-plated)"

−default: "Copper"

−```

−

−Bus bar joints shall be bolted with Belleville washers to maintain contact pressure under thermal cycling. All joint contact surfaces shall be silver-plated. Bus connections shall be designed to be accessible for re-torquing during maintenance without de-energizing adjacent sections.

−

−Phase bus shall be fully insulated with flame-retardant material rated for the operating temperature of the bus. Bus insulation shall be continuous through barriers and bus transitions between sections.

−

−```datasheet

−label: Bus Extension Provisions

−type: radio

−options:

− - "No future extension"

− - "Provision for future extension at one end"

− - "Provision for future extension at both ends"

−default: "No future extension"

−```

−

−## Barriers and Compartmentalization

−

−Switchgear shall provide metal barriers between all functional units and between the bus compartment and cable compartment. Barriers shall prevent propagation of an arc fault from one compartment to adjacent compartments.

−

−Individual circuit breaker compartments shall allow insertion, withdrawal, and testing of any breaker without exposing personnel to energized components in adjacent compartments. Interlocks shall prevent opening compartment doors while the breaker is in the connected position.

−

−## Arc Resistance

−

−```datasheet

−label: Arc-Resistant Construction

−type: select

−options:

− - "Not required"

− - "Type 1 - Front only (accessible from front)"

− - "Type 2 - Front and rear"

− - "Type 2B - Front, rear, and sides"

− - "Type 2C - Front, rear, sides, and between units"

−default: "Not required"

−```

−

−Where arc-resistant construction is specified, switchgear shall be tested per IEEE C37.20.7 at the specified short-circuit current rating and duration. Arc-resistant design shall redirect arc gases through plenums or ducts to areas where personnel are not present. Pressure relief flaps and reinforced enclosure construction shall contain the arc event.

−

−Arc-resistant construction does not eliminate the need for arc flash hazard analysis per IEEE 1584. See [[sync/arc-flash-study]] for arc flash study requirements and labeling.

−

−## Infrared Scanning Provisions

−

−Enclosure shall include removable infrared inspection windows or cover plates at each bus joint, main breaker connections, and feeder breaker connections. Windows shall allow thermographic inspection of energized connections without removing covers or de-energizing equipment.

−

−# Circuit Breakers

−

−## Main Circuit Breaker

−

−Circuit breakers shall comply with IEEE C37.13 and shall be drawout, stored-energy type with manual charging and electrical close/trip capability. Each breaker shall have three distinct positions: connected, test, and disconnected. It shall not be possible to move a breaker between positions with the door closed unless motor operators are provided.

−

−```datasheet

−label: Main Breaker Configuration

−type: select

−options:

− - "Power circuit breaker (drawout)"

− - "Main lugs only (no main breaker)"

−default: "Power circuit breaker (drawout)"

−```

−

−Main breaker frame size and trip rating shall be [[drawing: as indicated on the one-line diagram]].

−

−```datasheet

−label: Main Breaker Trip Unit

−type: select

−options:

− - "Electronic trip - LSI (Long-time, Short-time, Instantaneous)"

− - "Electronic trip - LSIG (Long-time, Short-time, Instantaneous, Ground Fault)"

−default: "Electronic trip - LSIG (Long-time, Short-time, Instantaneous, Ground Fault)"

−```

−

−LSIG trip units are recommended for all applications. Ground fault protection is required by NFPA 70 Article 230.95 for solidly grounded wye services of more than 150V to ground and 1000A or more. Even where not code-required, ground fault protection significantly reduces equipment damage from arcing faults.

−

−## Arc Flash Mitigation

−

−NFPA 70 Article 240.87 requires that circuit breakers rated 1200A or more have one of the following arc energy reduction methods. Specify the method appropriate for the project's operating requirements.

−

−```datasheet

−label: Arc Energy Reduction Method (1200A+ Breakers)

−type: select

−options:

− - "Zone-selective interlocking (ZSI)"

− - "Energy reducing maintenance switch (ERMS)"

− - "Energy reducing active arc flash mitigation system"

− - "Approved equivalent method"

−default: "Zone-selective interlocking (ZSI)"

−```

−

−Zone-selective interlocking allows upstream breakers to delay tripping only when a downstream breaker detects the fault, reducing arc flash energy at the upstream equipment while maintaining coordination. This is the most common method and does not require any mode switching for maintenance activities.

−

−## Feeder Circuit Breakers

−

−Feeder breaker sizes, quantities, and trip ratings are [[drawing: as indicated on the one-line diagram and panel/breaker schedules]].

−

−```datasheet

−label: Feeder Breaker Type

−type: select

−options:

− - "Power circuit breaker (drawout)"

− - "Insulated case circuit breaker (drawout)"

−default: "Power circuit breaker (drawout)"

−```

−

−```datasheet

−label: Feeder Breaker Trip Units

−type: select

−options:

− - "Electronic trip - LSI"

− - "Electronic trip - LSIG"

− - "Combination per breaker schedule"

−default: "Electronic trip - LSI"

−```

−

−```datasheet

−label: Breaker Accessories (All Breakers)

−type: checkbox

−options:

− - "Auxiliary contacts (1a + 1b minimum)"

− - "Shunt trip"

− - "Undervoltage release"

− - "Mechanical interlock (paired breakers)"

− - "Kirk key interlock"

− - "Motor operator with remote close/trip"

− - "Breaker position indication (drawout connected/test/disconnected)"

−default: "Auxiliary contacts (1a + 1b minimum)"

−```

−

−Auxiliary contacts shall be provided on every breaker regardless of other accessory selections. Contacts shall indicate breaker open/close status and shall be wired to terminal blocks accessible without removing the breaker from its compartment.

−

−## Breaker Drawout Mechanism

−

−All breakers shall be fully drawout and interchangeable within a given frame size. A manual racking mechanism shall allow movement between connected, test, and disconnected positions. The racking mechanism shall include a mechanical position indicator visible from the front of the switchgear and a means to padlock the breaker in any of the three positions.

−

−Self-aligning primary disconnects shall engage automatically when the breaker is racked to the connected position. Secondary disconnects for control wiring shall engage at the test position. It shall be possible to operate the breaker electrically in the test position for trip testing without energizing the primary circuit.

−

−# Protective Relaying

−

−```datasheet

−label: Protective Relay Functions

−type: checkbox

−options:

− - "Overcurrent (50/51)"

− - "Ground fault (50G/51G)"

− - "Bus differential (87B)"

− - "Under/overvoltage (27/59)"

− - "Under/overfrequency (81)"

− - "Breaker failure (50BF)"

− - "Reverse power (32)"

−default: "Overcurrent (50/51)"

−```

−

−Protective relays shall comply with IEEE C37.90 and shall be microprocessor-based with digital displays, self-diagnostics, and event recording. Relays shall be tested per IEEE C37.90.1 for surge withstand capability.

−

−Protection coordination study shall be performed per [[sync/protective-coordination-study]]. Relay settings are [[drawing: as indicated on the relay setting schedule]].

−

−# Metering and Instrumentation

−

−## Instrument Transformers

−

−Current transformers shall comply with IEEE C57.13. Accuracy class shall be appropriate for the connected metering:

−

−- Revenue metering: Class 0.3 accuracy

−- Protective relaying: Class C200 or higher

−- General monitoring: Class 0.6 accuracy

−

−Current transformers for metering and relaying shall be provided on separate cores. Do not share CTs between metering and protection functions.

−

−## Power Monitoring

−

−```datasheet

−label: Metering Type

−type: select

−options:

− - "No metering"

− - "Digital multifunction meter (main only)"

− - "Digital multifunction meter (main and feeders)"

− - "Revenue-grade metering per utility requirements"

−default: "Digital multifunction meter (main only)"

−```

−

−```datasheet

−label: Meter Functions

−type: checkbox

−options:

− - "Voltage (L-L, L-N all phases)"

− - "Current (per phase and neutral)"

− - "Power factor (per phase and total)"

− - "kW / kVA / kVAR (demand and instantaneous)"

− - "kWh / kVARh energy accumulation"

− - "Harmonics (THD per phase, individual to 31st)"

− - "Min/max recording with time stamp"

− - "Waveform capture"

−default: "Voltage (L-L, L-N all phases)"

−```

−

−```datasheet

−label: Metering Communication Protocol

−type: select

−options:

− - "No communications"

− - "Modbus RTU (RS-485)"

− - "Modbus TCP/IP (Ethernet)"

− - "BACnet IP"

− - "DNP3"

−default: "Modbus TCP/IP (Ethernet)"

−```

−

−Where building energy code requires submetering (ASHRAE 90.1 Section 8.4.3 or local amendments), meter data shall be accessible via the selected communication protocol for integration with the building management system. Coordinate communication wiring and protocols with [[sync/building-automation]].

−

−# Finish and Identification

−

−Enclosure shall receive a minimum two-coat paint system: corrosion-resistant primer and manufacturer's standard polyester powder coat finish. Minimum total dry film thickness shall be 3 mils (75 microns).

−

−```datasheet

−label: Finish Color

−type: text

−default: "ANSI 61 gray"

−```

−

−For outdoor installations or environments classified C3 or higher, an enhanced paint system with a minimum of 5 mils dry film thickness shall be applied. All internal structural members shall receive the same corrosion treatment as exterior surfaces.

−

−## Labeling

−

−Manufacturer shall provide engraved phenolic nameplates for the switchgear assembly and each individual device. Nameplates shall identify:

−

−- Switchgear designation and one-line reference

−- Bus ratings (voltage, continuous current, short-circuit)

−- Individual breaker designation, frame size, and trip rating

−- Current transformer ratios and accuracy class

−- Arc flash warning labels per NFPA 70E and IEEE 1584

−

−```datasheet

−label: Nameplate Material

−type: radio

−options:

− - "Laminated phenolic (indoor)"

− - "Stainless steel (outdoor or corrosive)"

− - "Aluminum (anodized)"

−default: "Laminated phenolic (indoor)"

−```

−

−Mimic bus diagram shall be provided on the front of the switchgear showing the bus configuration, breaker positions, and instrument transformer locations. Equipment labeling shall follow [[sync/equipment-labeling]] conventions.

−

−# Testing

−

−## Factory Tests

−

−The manufacturer shall perform the following production tests on the completed switchgear assembly per IEEE C37.51:

−

−- 60 Hz dielectric withstand test on primary bus

−- Insulation resistance measurement on each phase and neutral bus

−- Mechanical operation of each circuit breaker (minimum 5 open/close cycles)

−- Electrical operation of each circuit breaker (trip and close)

−- Ground fault sensing system functional test

−- Control wiring continuity verification

−- Current transformer ratio and polarity test

−- Protective relay functional test (verify trip at set values)

−- Visual and dimensional inspection

−

−```datasheet

−label: Factory Acceptance Test

−type: radio

−options:

− - "Witnessed by Owner's representative"

− - "Unwitnessed with certified test report"

− - "Not required beyond standard production tests"

−default: "Witnessed by Owner's representative"

−```

−

−Where witnessed factory testing is specified, the manufacturer shall provide a minimum of two weeks advance notice of test readiness. Test procedures shall be submitted for review prior to testing.

−

−## Field Acceptance Tests

−

−Contractor shall engage a qualified independent testing firm to perform acceptance testing per NETA ATS. Testing shall occur after installation is complete and before the equipment is energized.

−

−```datasheet

−label: Field Testing Requirements

−type: radio

−options:

− - "NETA acceptance testing and manufacturer startup"

− - "NETA acceptance testing only"

− - "Manufacturer startup only"

−default: "NETA acceptance testing and manufacturer startup"

−```

−

−Field acceptance tests shall include as a minimum:

−

−- Visual and mechanical inspection of all sections

−- Insulation resistance testing (phase-to-phase and phase-to-ground)

−- Contact resistance measurement on all bolted bus connections

−- Circuit breaker operational testing (mechanical and electrical)

−- Protective relay calibration verification

−- Primary current injection testing of all trip functions (long-time, short-time,

− instantaneous, ground fault pickup and time delay)

−- Current transformer ratio and polarity verification

−- Metering accuracy verification

−- Ground impedance measurement per IEEE 81

−- Functional testing of all control circuits, interlocks, and alarms

−

−```datasheet

−label: Infrared Thermographic Inspection

−type: radio

−options:

− - "Initial scan within 90 days of energization, follow-up at 11 months"

− - "Initial scan within 90 days of energization only"

− - "Not required"

−default: "Initial scan within 90 days of energization, follow-up at 11 months"

−```

−

−Infrared scanning shall be performed under normal operating load conditions (minimum 40% of rated load). All connections exceeding 10°C rise above ambient shall be reported and corrected. Follow-up scan at 11 months captures connections that may loosen during the initial thermal cycling period.

−

−# Installation

−

−## Concrete Housekeeping Pad

−

−Switchgear shall be mounted on a reinforced concrete housekeeping pad extending a minimum of 3 in. beyond the base of the equipment on all sides. Pad shall be a minimum of 4 in. above finished floor for indoor installations and 6 in. above finished grade for outdoor installations.

−

−Coordinate pad dimensions, conduit penetrations, and anchor bolt locations with equipment shop drawings prior to concrete placement. See [[sync/concrete-pads]] for construction requirements.

−

−## Equipment Setting

−

−Contractor shall comply with manufacturer's installation instructions and applicable rigging requirements. Remove all temporary shipping braces, blocking, and desiccants prior to final assembly. Verify section alignment and bolt all sections together per manufacturer's torque specifications.

−

−After assembly, verify the following before energizing:

−

−- All shipping restraints and temporary grounds removed

−- Bus joint torque verified per manufacturer's specifications using calibrated

− torque wrench

−- All circuit breakers rack and operate freely in all three positions

−- Conduit terminations sealed and cable connections torqued

−- Space heaters energized (outdoor or unconditioned installations)

−- Working clearances per NFPA 70 Article 110.26 are maintained

−

−## Working Clearance

−

−Minimum working space shall be maintained per NFPA 70 Article 110.26 based on the nominal voltage and accessibility configuration:

−

−| Voltage | Condition 1 (exposed on one side) | Condition 2 (exposed on both sides) |

−|---------|-----------------------------------|--------------------------------------|

−| 0-150V | 36 in. | 36 in. |

−| 151-600V | 36 in. | 48 in. |

−

−Working space shall not be used for storage. Dedicated electrical space above and below the equipment shall be maintained per NFPA 70 Article 110.26(E).

−

−# Delivery, Storage, and Handling

−

−Switchgear shall be shipped in the largest factory-assembled sections that can be transported to and within the installation site. Verify all pathway dimensions (doors, hallways, elevator shafts) between the delivery point and the final installation location prior to ordering.

−

−Equipment shall be stored indoors in a clean, dry location. Where indoor storage is not available, the manufacturer shall provide weatherproof packaging. Condensation heaters shall be connected and energized during storage if the equipment will be stored for more than 30 days or if the storage environment is not climate-controlled.

−

−# Warranty

−

−```datasheet

−label: Warranty Period

−type: select

−options:

− - "1 year from substantial completion"

− - "2 years from substantial completion"

− - "3 years from substantial completion"

− - "5 years from substantial completion"

−default: "1 year from substantial completion"

−```

−

−Warranty shall cover defects in materials and workmanship under normal use and service conditions. The manufacturer shall maintain a service organization capable of providing emergency replacement parts and field service within 24 hours during the warranty period.

−

−```datasheet

−label: Extended Warranty Coverage

−type: checkbox

−options:

− - "Parts only"

− - "Parts and labor"

− - "Emergency response (24/7 with 4-hour commitment)"

− - "Scheduled preventive maintenance (annual)"

−default: "Parts only"

−```

−

−# Spare Parts

−

−```datasheet

−label: Spare Breakers

−type: radio

−options:

− - "None"

− - "One spare of each frame size"

− - "10% of each frame size (minimum one)"

−default: "One spare of each frame size"

−```

−

−Spare breakers shall be of the same type, rating, and configuration as the installed breakers and shall be fully interchangeable. Spare breakers shall be stored in a manufacturer-provided storage cabinet or on a breaker storage truck, located in the electrical room.

−

−Manufacturer shall provide the following additional spare parts:

−

−- One set of replacement fuses for each fuse type and rating installed

−- One set of replacement indicating lights for each type installed

−- One set of racking handle, breaker test plugs, and portable closing tools

−- One complete set of keys for all locks

+---

+title: Low Voltage Switchgear

+category: Power Distribution

+toc_depth: 3

+description: >

+ When to use: Metal-enclosed, low voltage power circuit breaker switchgear rated 600V and below for commercial, institutional, and industrial facilities. Covers indoor and outdoor configurations with drawout power circuit breakers. Not intended for: Panelboards (see [[sync/low-voltage-panelboards]]), switchboards (see [[sync/low-voltage-switchboards]]), motor control centers (see [[sync/motor-control-centers]]), or medium voltage switchgear above 600V (see [[sync/medium-voltage-switchgear]]).

+---

+# Scope {toc}

+## This specification covers metal-enclosed, low voltage power circuit breaker switchgear assemblies rated 600V and below. {note}

+## Switchgear covered by this standard utilizes individually mounted drawout power circuit breakers as the primary switching and protective devices. {note}

+## For applications using molded case or insulated case breakers in a non-drawout configuration, see [[sync/low-voltage-switchboards]]. {note}

+## For medium voltage switchgear rated above 600V, see [[sync/medium-voltage-switchgear]]. {note}

+## Grounding and bonding per [[sync/grounding-and-bonding]]. {note}

+## Equipment shall comply with UL 1558 and IEEE C37.20.1 and shall be listed and labeled by a Nationally Recognized Testing Laboratory (NRTL).

+# Referenced Standards {toc}

+## Equipment and installation shall comply with the latest edition of the following.

+| Standard | Title |

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

+| UL 1558 | Metal-Enclosed Low-Voltage Power Circuit Breaker Switchgear |

+| IEEE C37.20.1 | Metal-Enclosed Low-Voltage Power Circuit Breaker Switchgear |

+| IEEE C37.13 | Low-Voltage AC Power Circuit Breakers Used in Enclosures |

+| IEEE C37.20.7 | Arc-Resistance Testing of Metal-Enclosed Switchgear |

+| IEEE C37.51 | Conformance Testing of Metal-Enclosed LV AC Power Circuit Breaker Switchgear |

+| IEEE C37.90 | Relays and Relay Systems Associated with Electric Power Apparatus |

+| IEEE C57.13 | Requirements for Instrument Transformers |

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

+| NFPA 70 | National Electrical Code |

+| NEMA ICS 6 | Industrial Control and Systems: Enclosures |

+| NETA ATS | Acceptance Testing Specifications for Electrical Power Equipment and Systems |

+| ASCE 7 | Minimum Design Loads and Associated Criteria for Buildings |

+| ASHRAE 90.1 | Energy Standard for Buildings (submetering requirements) |

+| ANSI/NEMA SG 3 | Low-Voltage Power Circuit Breakers |

+## Equipment and installation shall comply with the latest edition of the standards listed above.

+## Where conflicts exist between referenced standards, the more stringent requirement shall govern unless otherwise directed by the Engineer of Record.

+# Submittals {toc}

+## Action Submittals {toc}

+### Contractor shall submit the following for review prior to fabrication:

+- Shop drawings showing front, side, and rear elevations with overall dimensions

+- Single line diagram indicating breaker frame sizes, trip ratings, and bus configuration

+- Bill of materials listing all major components

+- Breaker time-current coordination curves for all protective devices

+- Control schematic and wiring diagrams

+- Seismic certification documentation, where required

+```datasheet

+label: Submittal Documentation

+type: checkbox

+options:

+ - "Shop drawings (front, side, rear elevations)"

+ - "Single line diagram"

+ - "Bill of materials"

+ - "Time-current coordination curves"

+ - "Control schematics and wiring diagrams"

+ - "Seismic certification (IBC/ASCE 7)"

+ - "Arc flash calculation input data"

+ - "Catalog cut sheets for all protective devices"

+default: "Shop drawings (front, side, rear elevations)"

+```

+### Contractor shall submit the action submittals listed above for review prior to fabrication.

+## Closeout Submittals {toc}

+### Contractor shall provide at substantial completion:

+- Operation and maintenance manuals, bound with table of contents

+- As-built shop drawings reflecting field modifications

+- Factory and field test reports

+- Warranty documentation

+- Spare parts inventory with reorder information

+```datasheet

+label: Closeout Submittals

+type: checkbox

+options:

+ - "Operation and maintenance manuals, bound with table of contents"

+ - "As-built shop drawings reflecting field modifications"

+ - "Factory and field test reports"

+ - "Warranty documentation"

+ - "Spare parts inventory with reorder information"

+default: [Operation and maintenance manuals, bound with table of contents, As-built shop drawings reflecting field modifications, Factory and field test reports, Warranty documentation, Spare parts inventory with reorder information]

+```

+### Contractor shall provide the closeout submittals listed above at substantial completion.

+# Quality Assurance {toc}

+## Manufacturer Qualifications {toc}

+### Switchgear shall be manufactured by a single company responsible for the assembly, bus, and all integral protective devices.

+### The manufacturer shall have a minimum of five years documented experience producing UL 1558 listed switchgear.

+### The manufacturer shall maintain an ISO 9001 certified quality management system.

+### The manufacturer shall maintain a 24/7 service organization with factory-trained field representatives available within 24 hours of notification.

+## Source Limitations {toc}

+### All switchgear sections, bus, circuit breakers, protective relays, and metering equipment shall be produced or furnished by the switchgear manufacturer as an integrated assembly.

+### Third-party components assembled by others are not acceptable.

+## Testing Personnel Qualifications {toc}

+### Acceptance testing shall be performed by a firm regularly engaged in testing electrical power equipment, employing technicians certified by NETA or equivalent.

+### Testing personnel shall have a minimum of three years experience testing low voltage switchgear assemblies.

+# Environmental and Service Conditions {toc}

+## Switchgear shall be suitable for continuous operation under the following ambient conditions.

+## Where site conditions exceed these parameters, notify the manufacturer and derate equipment accordingly. {note}

+```datasheet

+label: Ambient Temperature (Maximum)

+type: select

+unit: °C

+options:

+ - "40°C (standard rating)"

+ - "50°C (tropical rating)"

+ - "55°C (desert/rooftop rating)"

+default: "40°C (standard rating)"

+```

+```datasheet

+label: Installation Altitude

+type: select

+options:

+ - "Below 6,600 ft (2,000 m) - No derating"

+ - "6,600 - 9,900 ft (2,000 - 3,000 m) - Derating required"

+ - "Above 9,900 ft (3,000 m) - Consult manufacturer"

+default: "Below 6,600 ft (2,000 m) - No derating"

+```

+```datasheet

+label: Corrosion Severity

+type: select

+options:

+ - "C2 - Low (indoor, climate-controlled)"

+ - "C3 - Medium (indoor, unconditioned)"

+ - "C4 - High (coastal, chemical exposure)"

+ - "C5 - Very High (industrial, marine)"

+default: "C2 - Low (indoor, climate-controlled)"

+```

+## See [[sync/electrical-rooms]] for room environmental classification requirements. {note}

+## Switchgear shall be suitable for continuous operation under the specified ambient conditions.

+## Where site conditions exceed the specified parameters, the Contractor shall notify the manufacturer and derate equipment accordingly.

+## Equipment rated for standard conditions (40°C, below 6,600 ft) shall be derated per IEEE C37.20.1 when installed outside these parameters.

+## The Engineer shall document derating calculations on the contract drawings.

+## For installations classified C4 or C5, bus bars shall be copper (tin or silver-plated).

+## For installations classified C4 or C5, enclosure paint systems shall provide enhanced corrosion protection per IEEE C57.12.29.

+## Seismic Requirements {toc}

+```datasheet

+label: Seismic Certification

+type: select

+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: "Not required"

+```

+### Where required by the applicable building code, switchgear shall be seismically certified by shake-table testing per ICC ES AC156 or by analysis per ASCE 7.

+### Seismic certification shall be by an independent third-party testing laboratory.

+### Certification shall cover the complete assembly including all circuit breakers, bus, and ancillary components as installed.

+### Certification of individual components in isolation is not acceptable.

+# Electrical Requirements {toc}

+## System Ratings {toc}

+```datasheet

+label: Service Entrance Equipment

+type: radio

+options:

+ - "Yes - Main Service Entrance"

+ - "No - Downstream Distribution"

+default: "No - Downstream Distribution"

+```

+```datasheet

+label: System Voltage

+type: select

+options:

+ - "120/208V 3-Phase 4-Wire"

+ - "277/480V 3-Phase 4-Wire"

+ - "480V 3-Phase 3-Wire"

+default: "277/480V 3-Phase 4-Wire"

+```

+```datasheet

+label: System Frequency

+type: radio

+unit: Hz

+options:

+ - "60 Hz"

+ - "50 Hz"

+default: "60 Hz"

+```

+### Where switchgear serves as main service entrance equipment, it shall comply with NFPA 70 Article 230 including provisions for metering, service disconnect, and available fault current labeling.

+### The Contractor shall coordinate metering requirements with the serving utility prior to submittal.

+## Bus Rating {toc}

+### Main bus continuous current rating shall be [[drawing: as indicated on the one-line diagram]].

+```datasheet

+label: Main Bus Continuous Current

+type: range

+unit: A

+drawing_ref: true

+options:

+ min: 800

+ max: 5000

+ setpoints: [800, 1200, 1600, 2000, 2500, 3000, 4000, 5000]

+default: 1600

+```

+```datasheet

+label: Short-Circuit Current Rating

+type: select

+unit: kAIC

+options:

+ - "42 kAIC"

+ - "65 kAIC"

+ - "85 kAIC"

+ - "100 kAIC"

+ - "200 kAIC"

+default: "65 kAIC"

+```

+```datasheet

+label: Short-Time Withstand Rating

+type: select

+options:

+ - "30-cycle (0.5 seconds)"

+ - "15-cycle (0.25 seconds)"

+default: "30-cycle (0.5 seconds)"

+```

+### Main bus continuous current rating shall be as indicated on the one-line diagram.

+### Bus shall be braced for the available short-circuit current at the point of installation as determined by a short-circuit analysis per IEEE 551.

+### Short-circuit current rating shall equal or exceed the available fault current at the switchgear terminals.

+### The Contractor shall verify available fault current with the utility provider and perform a short-circuit study per [[sync/short-circuit-study]] prior to equipment procurement.

+## Neutral and Ground Bus {toc}

+```datasheet

+label: Neutral Bus Rating

+type: select

+options:

+ - "Full rated (100% of main bus)"

+ - "Reduced (50% of main bus)"

+ - "Oversized (200% of main bus)"

+ - "Not applicable (3-wire system)"

+default: "Full rated (100% of main bus)"

+```

+```datasheet

+label: Ground Bus

+type: radio

+options:

+ - "Included - Full length of assembly"

+ - "Not required"

+default: "Included - Full length of assembly"

+```

+### Oversized neutral bus is required where nonlinear loads exceed 30% of the total connected load to accommodate triplen harmonic currents.

+### The Engineer shall evaluate harmonic loading per IEEE 519 when selecting neutral bus sizing.

+### Ground bus shall be bare copper, minimum 1/4 in. x 2 in. cross-section, extending the full length of the switchgear assembly.

+### Ground bus shall be accessible without removing any covers or barriers required for safe operation.

+# Physical Construction {toc}

+## Enclosure {toc}

+```datasheet

+label: Enclosure Rating

+type: select

+options:

+ - "NEMA 1 - Indoor General Purpose"

+ - "NEMA 3R - Outdoor Rainproof"

+ - "NEMA 12 - Industrial (dust-tight)"

+default: "NEMA 1 - Indoor General Purpose"

+```

+```datasheet

+label: Front Accessibility

+type: radio

+options:

+ - "Front accessible only"

+ - "Front and rear accessible"

+default: "Front accessible only"

+```

+### Switchgear overall dimensions and arrangement shall be [[drawing: per the equipment room layout drawings]].

+### Enclosure shall be fabricated from galvanized steel with a minimum thickness of 12 gauge (2.66 mm) for structural members and 14 gauge (1.90 mm) for covers and doors.

+### All joints shall be continuously welded or bolted with gaskets as required for the specified NEMA rating.

+### For outdoor installations (NEMA 3R), enclosure shall include sun shields, rain hoods over ventilation openings, and condensation heaters in each section.

+### For outdoor installations (NEMA 3R), heater sizing shall be a minimum of 250W per vertical section.

+### For outdoor installations (NEMA 3R), heaters shall be thermostat controlled and wired to remain energized whenever the switchgear is de-energized.

+### Rear-accessible configurations require minimum 36 in. working clearance at rear per NFPA 70 Article 110.26.

+### Rear compartments shall have individual hinged doors with padlockable latches.

+### Switchgear overall dimensions and arrangement shall be per the equipment room layout drawings.

+## Bus Bars {toc}

+```datasheet

+label: Bus Bar Material

+type: radio

+options:

+ - "Copper"

+ - "Copper (tin-plated)"

+ - "Copper (silver-plated)"

+default: "Copper"

+```

+```datasheet

+label: Bus Extension Provisions

+type: radio

+options:

+ - "No future extension"

+ - "Provision for future extension at one end"

+ - "Provision for future extension at both ends"

+default: "No future extension"

+```

+### Bus bar joints shall be bolted with Belleville washers to maintain contact pressure under thermal cycling.

+### All joint contact surfaces shall be silver-plated.

+### Bus connections shall be designed to be accessible for re-torquing during maintenance without de-energizing adjacent sections.

+### Phase bus shall be fully insulated with flame-retardant material rated for the operating temperature of the bus.

+### Bus insulation shall be continuous through barriers and bus transitions between sections.

+## Barriers and Compartmentalization {toc}

+### Switchgear shall provide metal barriers between all functional units and between the bus compartment and cable compartment.

+### Barriers shall prevent propagation of an arc fault from one compartment to adjacent compartments.

+### Individual circuit breaker compartments shall allow insertion, withdrawal, and testing of any breaker without exposing personnel to energized components in adjacent compartments.

+### Interlocks shall prevent opening compartment doors while the breaker is in the connected position.

+## Arc Resistance {toc}

+```datasheet

+label: Arc-Resistant Construction

+type: select

+options:

+ - "Not required"

+ - "Type 1 - Front only (accessible from front)"

+ - "Type 2 - Front and rear"

+ - "Type 2B - Front, rear, and sides"

+ - "Type 2C - Front, rear, sides, and between units"

+default: "Not required"

+```

+### See [[sync/arc-flash-study]] for arc flash study requirements and labeling. {note}

+### Where arc-resistant construction is specified, switchgear shall be tested per IEEE C37.20.7 at the specified short-circuit current rating and duration.

+### Arc-resistant design shall redirect arc gases through plenums or ducts to areas where personnel are not present.

+### Pressure relief flaps and reinforced enclosure construction shall contain the arc event.

+### Arc-resistant construction does not eliminate the need for arc flash hazard analysis per IEEE 1584. {note}

+## Infrared Scanning Provisions {toc}

+### Enclosure shall include removable infrared inspection windows or cover plates at each bus joint, main breaker connections, and feeder breaker connections.

+### Windows shall allow thermographic inspection of energized connections without removing covers or de-energizing equipment.

+# Circuit Breakers {toc}

+## Main Circuit Breaker {toc}

+```datasheet

+label: Main Breaker Configuration

+type: select

+options:

+ - "Power circuit breaker (drawout)"

+ - "Main lugs only (no main breaker)"

+default: "Power circuit breaker (drawout)"

+```

+```datasheet

+label: Main Breaker Trip Unit

+type: select

+options:

+ - "Electronic trip - LSI (Long-time, Short-time, Instantaneous)"

+ - "Electronic trip - LSIG (Long-time, Short-time, Instantaneous, Ground Fault)"

+default: "Electronic trip - LSIG (Long-time, Short-time, Instantaneous, Ground Fault)"

+```

+### Main breaker frame size and trip rating shall be [[drawing: as indicated on the one-line diagram]].

+### Circuit breakers shall comply with IEEE C37.13 and shall be drawout, stored-energy type with manual charging and electrical close/trip capability.

+### Each breaker shall have three distinct positions: connected, test, and disconnected.

+### It shall not be possible to move a breaker between positions with the door closed unless motor operators are provided.

+### Main breaker frame size and trip rating shall be as indicated on the one-line diagram.

+### LSIG trip units are recommended for all applications. {note}

+### Ground fault protection is required by NFPA 70 Article 230.95 for solidly grounded wye services of more than 150V to ground and 1000A or more.

+### Even where not code-required, ground fault protection significantly reduces equipment damage from arcing faults. {note}

+## Arc Flash Mitigation {toc}

+### NFPA 70 Article 240.87 requires that circuit breakers rated 1200A or more have one of the following arc energy reduction methods. {note}

+### Specify the method appropriate for the project's operating requirements. {note}

+```datasheet

+label: Arc Energy Reduction Method (1200A+ Breakers)

+type: select

+options:

+ - "Zone-selective interlocking (ZSI)"

+ - "Energy reducing maintenance switch (ERMS)"

+ - "Energy reducing active arc flash mitigation system"

+ - "Approved equivalent method"

+default: "Zone-selective interlocking (ZSI)"

+```

+### Circuit breakers rated 1200A or more shall have one of the arc energy reduction methods listed above per NFPA 70 Article 240.87.

+### Zone-selective interlocking allows upstream breakers to delay tripping only when a downstream breaker detects the fault, reducing arc flash energy at the upstream equipment while maintaining coordination, and does not require any mode switching for maintenance activities. {note}

+## Feeder Circuit Breakers {toc}

+### Feeder breaker sizes, quantities, and trip ratings are [[drawing: as indicated on the one-line diagram and panel/breaker schedules]]. {note}

+```datasheet

+label: Feeder Breaker Type

+type: select

+options:

+ - "Power circuit breaker (drawout)"

+ - "Insulated case circuit breaker (drawout)"

+default: "Power circuit breaker (drawout)"

+```

+```datasheet

+label: Feeder Breaker Trip Units

+type: select

+options:

+ - "Electronic trip - LSI"

+ - "Electronic trip - LSIG"

+ - "Combination per breaker schedule"

+default: "Electronic trip - LSI"

+```

+```datasheet

+label: Breaker Accessories (All Breakers)

+type: checkbox

+options:

+ - "Auxiliary contacts (1a + 1b minimum)"

+ - "Shunt trip"

+ - "Undervoltage release"

+ - "Mechanical interlock (paired breakers)"

+ - "Kirk key interlock"

+ - "Motor operator with remote close/trip"

+ - "Breaker position indication (drawout connected/test/disconnected)"

+default: "Auxiliary contacts (1a + 1b minimum)"

+```

+### Feeder breaker sizes, quantities, and trip ratings shall be as indicated on the one-line diagram and panel/breaker schedules.

+### Auxiliary contacts shall be provided on every breaker regardless of other accessory selections.

+### Auxiliary contacts shall indicate breaker open/close status and shall be wired to terminal blocks accessible without removing the breaker from its compartment.

+## Breaker Drawout Mechanism {toc}

+### All breakers shall be fully drawout and interchangeable within a given frame size.

+### A manual racking mechanism shall allow movement between connected, test, and disconnected positions.

+### The racking mechanism shall include a mechanical position indicator visible from the front of the switchgear and a means to padlock the breaker in any of the three positions.

+### Self-aligning primary disconnects shall engage automatically when the breaker is racked to the connected position.

+### Secondary disconnects for control wiring shall engage at the test position.

+### It shall be possible to operate the breaker electrically in the test position for trip testing without energizing the primary circuit.

+# Protective Relaying {toc}

+```datasheet

+label: Protective Relay Functions

+type: checkbox

+options:

+ - "Overcurrent (50/51)"

+ - "Ground fault (50G/51G)"

+ - "Bus differential (87B)"

+ - "Under/overvoltage (27/59)"

+ - "Under/overfrequency (81)"

+ - "Breaker failure (50BF)"

+ - "Reverse power (32)"

+default: "Overcurrent (50/51)"

+```

+## Relay settings are [[drawing: as indicated on the relay setting schedule]]. {note}

+## Protective relays shall comply with IEEE C37.90 and shall be microprocessor-based with digital displays, self-diagnostics, and event recording.

+## Relays shall be tested per IEEE C37.90.1 for surge withstand capability.

+## Protection coordination study shall be performed per [[sync/protective-coordination-study]].

+## Relay settings shall be as indicated on the relay setting schedule.

+# Metering and Instrumentation {toc}

+## Instrument Transformers {toc}

+### Current transformers shall comply with IEEE C57.13.

+### Accuracy class shall be appropriate for the connected metering:

+- Revenue metering: Class 0.3 accuracy

+- Protective relaying: Class C200 or higher

+- General monitoring: Class 0.6 accuracy

+### Current transformers shall comply with IEEE C57.13.

+### Current transformer accuracy class shall be appropriate for the connected metering: Class 0.3 for revenue metering, Class C200 or higher for protective relaying, and Class 0.6 for general monitoring.

+### Current transformers for metering and relaying shall be provided on separate cores.

+### CTs shall not be shared between metering and protection functions.

+## Power Monitoring {toc}

+```datasheet

+label: Metering Type

+type: select

+options:

+ - "No metering"

+ - "Digital multifunction meter (main only)"

+ - "Digital multifunction meter (main and feeders)"

+ - "Revenue-grade metering per utility requirements"

+default: "Digital multifunction meter (main only)"

+```

+```datasheet

+label: Meter Functions

+type: checkbox

+options:

+ - "Voltage (L-L, L-N all phases)"

+ - "Current (per phase and neutral)"

+ - "Power factor (per phase and total)"

+ - "kW / kVA / kVAR (demand and instantaneous)"

+ - "kWh / kVARh energy accumulation"

+ - "Harmonics (THD per phase, individual to 31st)"

+ - "Min/max recording with time stamp"

+ - "Waveform capture"

+default: "Voltage (L-L, L-N all phases)"

+```

+```datasheet

+label: Metering Communication Protocol

+type: select

+options:

+ - "No communications"

+ - "Modbus RTU (RS-485)"

+ - "Modbus TCP/IP (Ethernet)"

+ - "BACnet IP"

+ - "DNP3"

+default: "Modbus TCP/IP (Ethernet)"

+```

+### Coordinate communication wiring and protocols with [[sync/building-automation]]. {note}

+### Where building energy code requires submetering (ASHRAE 90.1 Section 8.4.3 or local amendments), meter data shall be accessible via the selected communication protocol for integration with the building management system.

+### The Contractor shall coordinate communication wiring and protocols with [[sync/building-automation]].

+# Finish and Identification {toc}

+```datasheet

+label: Finish Color

+type: text

+default: "ANSI 61 gray"

+```

+## Enclosure shall receive a minimum two-coat paint system: corrosion-resistant primer and manufacturer's standard polyester powder coat finish.

+## Minimum total dry film thickness shall be 3 mils (75 microns).

+## For outdoor installations or environments classified C3 or higher, an enhanced paint system with a minimum of 5 mils dry film thickness shall be applied.

+## All internal structural members shall receive the same corrosion treatment as exterior surfaces.

+## Labeling {toc}

+### Manufacturer shall provide engraved phenolic nameplates for the switchgear assembly and each individual device.

+### Nameplates shall identify:

+- Switchgear designation and one-line reference

+- Bus ratings (voltage, continuous current, short-circuit)

+- Individual breaker designation, frame size, and trip rating

+- Current transformer ratios and accuracy class

+- Arc flash warning labels per NFPA 70E and IEEE 1584

+```datasheet

+label: Nameplate Material

+type: radio

+options:

+ - "Laminated phenolic (indoor)"

+ - "Stainless steel (outdoor or corrosive)"

+ - "Aluminum (anodized)"

+default: "Laminated phenolic (indoor)"

+```

+### Equipment labeling shall follow [[sync/equipment-labeling]] conventions.

+### Manufacturer shall provide engraved phenolic nameplates for the switchgear assembly and each individual device, identifying the switchgear designation and one-line reference, bus ratings (voltage, continuous current, short-circuit), individual breaker designation, frame size, and trip rating, current transformer ratios and accuracy class, and arc flash warning labels per NFPA 70E and IEEE 1584.

+### Mimic bus diagram shall be provided on the front of the switchgear showing the bus configuration, breaker positions, and instrument transformer locations.

+### Equipment labeling shall follow [[sync/equipment-labeling]] conventions.

+# Testing {toc}

+## Factory Tests {toc}

+### The manufacturer shall perform the following production tests on the completed switchgear assembly per IEEE C37.51:

+- 60 Hz dielectric withstand test on primary bus

+- Insulation resistance measurement on each phase and neutral bus

+- Mechanical operation of each circuit breaker (minimum 5 open/close cycles)

+- Electrical operation of each circuit breaker (trip and close)

+- Ground fault sensing system functional test

+- Control wiring continuity verification

+- Current transformer ratio and polarity test

+- Protective relay functional test (verify trip at set values)

+- Visual and dimensional inspection

+```datasheet

+label: Factory Acceptance Test

+type: radio

+options:

+ - "Witnessed by Owner's representative"

+ - "Unwitnessed with certified test report"

+ - "Not required beyond standard production tests"

+default: "Witnessed by Owner's representative"

+```

+### The manufacturer shall perform the production tests listed above on the completed switchgear assembly per IEEE C37.51.

+### Where witnessed factory testing is specified, the manufacturer shall provide a minimum of two weeks advance notice of test readiness.

+### Where witnessed factory testing is specified, test procedures shall be submitted for review prior to testing.

+## Field Acceptance Tests {toc}

+### Contractor shall engage a qualified independent testing firm to perform acceptance testing per NETA ATS.

+### Field acceptance tests shall include as a minimum:

+- Visual and mechanical inspection of all sections

+- Insulation resistance testing (phase-to-phase and phase-to-ground)

+- Contact resistance measurement on all bolted bus connections

+- Circuit breaker operational testing (mechanical and electrical)

+- Protective relay calibration verification

+- Primary current injection testing of all trip functions (long-time, short-time, instantaneous, ground fault pickup and time delay)

+- Current transformer ratio and polarity verification

+- Metering accuracy verification

+- Ground impedance measurement per IEEE 81

+- Functional testing of all control circuits, interlocks, and alarms

+```datasheet

+label: Field Testing Requirements

+type: radio

+options:

+ - "NETA acceptance testing and manufacturer startup"

+ - "NETA acceptance testing only"

+ - "Manufacturer startup only"

+default: "NETA acceptance testing and manufacturer startup"

+```

+```datasheet

+label: Infrared Thermographic Inspection

+type: radio

+options:

+ - "Initial scan within 90 days of energization, follow-up at 11 months"

+ - "Initial scan within 90 days of energization only"

+ - "Not required"

+default: "Initial scan within 90 days of energization, follow-up at 11 months"

+```

+### Contractor shall engage a qualified independent testing firm to perform acceptance testing per NETA ATS.

+### Acceptance testing shall occur after installation is complete and before the equipment is energized.

+### Field acceptance tests shall include as a minimum the inspections and tests listed above.

+### Infrared scanning shall be performed under normal operating load conditions (minimum 40% of rated load).

+### All connections exceeding 10°C rise above ambient shall be reported and corrected.

+### A follow-up scan at 11 months captures connections that may loosen during the initial thermal cycling period. {note}

+# Installation {toc}

+## Concrete Housekeeping Pad {toc}

+### See [[sync/concrete-pads]] for construction requirements. {note}

+### Switchgear shall be mounted on a reinforced concrete housekeeping pad extending a minimum of 3 in. beyond the base of the equipment on all sides.

+### Pad shall be a minimum of 4 in. above finished floor for indoor installations and 6 in. above finished grade for outdoor installations.

+### The Contractor shall coordinate pad dimensions, conduit penetrations, and anchor bolt locations with equipment shop drawings prior to concrete placement.

+## Equipment Setting {toc}

+### Before energizing, verify the following: {note}

+- All shipping restraints and temporary grounds removed

+- Bus joint torque verified per manufacturer's specifications using calibrated torque wrench

+- All circuit breakers rack and operate freely in all three positions

+- Conduit terminations sealed and cable connections torqued

+- Space heaters energized (outdoor or unconditioned installations)

+- Working clearances per NFPA 70 Article 110.26 are maintained

+### Contractor shall comply with manufacturer's installation instructions and applicable rigging requirements.

+### The Contractor shall remove all temporary shipping braces, blocking, and desiccants prior to final assembly.

+### The Contractor shall verify section alignment and bolt all sections together per manufacturer's torque specifications.

+### After assembly and before energizing, the Contractor shall verify the conditions listed above.

+## Working Clearance {toc}

+### Minimum working space shall be maintained per NFPA 70 Article 110.26 based on the nominal voltage and accessibility configuration:

+| Voltage | Condition 1 (exposed on one side) | Condition 2 (exposed on both sides) |

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

+| 0-150V | 36 in. | 36 in. |

+| 151-600V | 36 in. | 48 in. |

+### Minimum working space shall be maintained per NFPA 70 Article 110.26 based on the nominal voltage and accessibility configuration shown in the table above.

+### Working space shall not be used for storage.

+### Dedicated electrical space above and below the equipment shall be maintained per NFPA 70 Article 110.26(E).

+# Delivery, Storage, and Handling {toc}

+## Switchgear shall be shipped in the largest factory-assembled sections that can be transported to and within the installation site.

+## The Contractor shall verify all pathway dimensions (doors, hallways, elevator shafts) between the delivery point and the final installation location prior to ordering.

+## Equipment shall be stored indoors in a clean, dry location.

+## Where indoor storage is not available, the manufacturer shall provide weatherproof packaging.

+## Condensation heaters shall be connected and energized during storage if the equipment will be stored for more than 30 days or if the storage environment is not climate-controlled.

+# Warranty {toc}

+```datasheet

+label: Warranty Period

+type: select

+options:

+ - "1 year from substantial completion"

+ - "2 years from substantial completion"

+ - "3 years from substantial completion"

+ - "5 years from substantial completion"

+default: "1 year from substantial completion"

+```

+```datasheet

+label: Extended Warranty Coverage

+type: checkbox

+options:

+ - "Parts only"

+ - "Parts and labor"

+ - "Emergency response (24/7 with 4-hour commitment)"

+ - "Scheduled preventive maintenance (annual)"

+default: "Parts only"

+```

+## Warranty shall cover defects in materials and workmanship under normal use and service conditions.

+## The manufacturer shall maintain a service organization capable of providing emergency replacement parts and field service within 24 hours during the warranty period.

+# Spare Parts {toc}

+```datasheet

+label: Spare Breakers

+type: radio

+options:

+ - "None"

+ - "One spare of each frame size"

+ - "10% of each frame size (minimum one)"

+default: "One spare of each frame size"

+```

+## Spare breakers shall be of the same type, rating, and configuration as the installed breakers and shall be fully interchangeable.

+## Spare breakers shall be stored in a manufacturer-provided storage cabinet or on a breaker storage truck, located in the electrical room.

+## Manufacturer shall provide the following additional spare parts: one set of replacement fuses for each fuse type and rating installed, one set of replacement indicating lights for each type installed, one set of racking handle, breaker test plugs, and portable closing tools, and one complete set of keys for all locks.

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