Understanding the Electrical Inspection Process

Electrical inspections are conducted by the authority having jurisdiction (AHJ) — typically a municipal or county building department — to verify that electrical installations comply with the adopted edition of the National Electrical Code (NEC) and any local amendments. In a typical residential or light commercial project, inspections occur at two stages:

  1. Rough-In Inspection: After wiring is installed in walls, ceilings, and floors but before insulation and drywall cover the work. The inspector verifies box fill, conductor routing, conduit installation, and protection requirements.
  2. Final Inspection: After all devices, fixtures, panels, and equipment are installed and the system is ready for service. The inspector verifies GFCI/AFCI protection, panel labeling, grounding, and load calculations.

Some jurisdictions also conduct a service inspection before the utility connects power, focused specifically on the service entrance equipment.

Rough-In Inspection Checklist

Box Fill and Device Boxes (NEC 314)

  • All boxes properly secured and supported per NEC 314.23 — boxes must not rely solely on a single wiring method for support unless specifically permitted
  • Box fill calculations comply with NEC 314.16 — each conductor, device, and clamp counts as a specific volume in cubic inches
  • Boxes are positioned so the front edge is within 6mm (¼ inch) of the finished wall surface per NEC 314.20 for noncombustible materials, or flush with combustible surfaces
  • Unused knockouts are closed with appropriate fillers
  • Conductors are not damaged at entry points — check for insulation damage from staples or fasteners

Conductor Installation and Protection

  • NM (Romex) cable is protected from physical damage where run within 6 feet of the floor or through framing members that could be penetrated by screws or nails — NEC 334.15
  • Cables through studs and joists are centered or protected with nail plates when within 1.25 inches (32mm) of the edge per NEC 300.4
  • Conductors are supported within 12 inches of boxes and at intervals not exceeding 4.5 feet for NM cable per NEC 334.30
  • Appropriate cable type for the location — NM cable is not permitted in damp/wet locations, in concrete, or exposed in commercial applications where conduit is required
  • Conductor ampacity is appropriate for the overcurrent protection per NEC 310 and 240
  • All conductor splices are in accessible junction boxes — no splices are buried in walls without a box per NEC 300.15

Conduit and Raceway Systems (NEC Articles 342–388)

  • Conduit fill does not exceed the limits in NEC Chapter 9, Table 1 (40% fill for 3 or more conductors)
  • Conduit is properly supported at the intervals required for the conduit type (EMT every 10 feet and within 3 feet of boxes per NEC 358.30)
  • All conduit ends have bushings or fittings to protect conductors from sharp edges
  • Conduit bodies (LB, LL, LR) are properly sized for conductors and accessible
  • Expansion fittings are used where required for thermal expansion in long conduit runs

Service Entrance Inspection Checklist

Service Drop and Service Entrance Conductors (NEC Article 230)

  • Service entrance conductors are sized for the calculated load per NEC 230.42 (minimum 100A for dwellings per 230.79)
  • Overhead service conductors maintain the required clearances: 10 feet above finished grade at the point of attachment; 12 feet above residential driveways; 18 feet above public streets per NEC 230.24
  • Service entrance conductors maintain 3-foot clearance from windows that open, doors, porches, balconies, ladders, stairs, fire escapes, or similar locations per NEC 230.9 (unless the conductors run directly above the opening)
  • Point of attachment is not less than 10 feet above grade and properly supported per NEC 230.26 and 230.27
  • Service mast (if present) is adequately supported and weatherhead is positioned to prevent water entry
  • Service entrance cable or conduit is properly sealed to prevent moisture entry into the panel

Service Disconnect and Metering (NEC 230.70–230.82)

  • Service disconnect is located at or nearest the point of entrance of the service conductors per NEC 230.70
  • Service disconnect is accessible, externally operable, and permanently marked to identify it as the service disconnect per NEC 230.70(B)
  • Not more than six disconnects (or one main disconnect) per the "six-handle rule" of NEC 230.71
  • Service entrance equipment is listed for service entrance use and rated for the available fault current (interrupting capacity)

Panel Inspection Checklist

Working Clearance and Enclosure (NEC 110.26)

  • Minimum 36-inch clear working space in front of the panel (depth from front of panel) per NEC 110.26(A)(1) — deeper clearances required for higher voltages
  • Minimum 30-inch wide working space; at least as wide as the equipment per NEC 110.26(A)(2)
  • Minimum 6.5-foot headroom in front of the panel per NEC 110.26(A)(3)
  • Dedicated space 6 feet above and below the panel (to the ceiling structural element) free from foreign systems per NEC 110.26(F)
  • Panel is not located in bathrooms, clothes closets, or stairwells per NEC 240.24(E) and (D)
  • Panel door opens at least 90 degrees

Overcurrent Protective Devices and Wiring

  • All breakers are listed and rated for the panel — only listed breakers for the panel manufacturer are permitted per UL 67 and NEC 110.3
  • Tandem (twin) breakers only installed in positions listed for tandem use per the panel's labeling
  • All breakers are labeled on the directory inside the door per NEC 408.4 — the directory must accurately describe the load served
  • Conductors are properly landed — insulation stripped to the correct length, no nick marks on conductors, proper torque applied (many inspectors now check for torque marks)
  • Neutral conductors and grounding conductors are not cross-connected on sub-panels (they must be separated except at the main service) per NEC 250.24(A)(5)
  • Unused openings in the panel enclosure are closed per NEC 408.7
  • All knockout holes have the proper number of conductors or are sealed

GFCI and AFCI Protection Checklist

GFCI Protection Locations (NEC 210.8)

  • All 125V, 15A and 20A receptacles in bathrooms — NEC 210.8(A)(1)
  • All receptacles in garages and accessory buildings with a floor at or below grade — NEC 210.8(A)(2)
  • All outdoor receptacles — NEC 210.8(A)(3)
  • All receptacles in crawl spaces at or below grade — NEC 210.8(A)(4)
  • All receptacles in unfinished basements — NEC 210.8(A)(5)
  • Kitchen countertop receptacles within 6 feet of a sink — NEC 210.8(A)(6)
  • Boathouses — NEC 210.8(A)(7)
  • All receptacles within 6 feet of bathtubs or shower stalls — NEC 210.8(A)(8)
  • Receptacles in garages, service bays, and similar areas in commercial occupancies — NEC 210.8(B)

AFCI Protection Locations (NEC 210.12)

  • All 120V, 15A and 20A branch circuits supplying outlets in dwelling unit bedrooms, living rooms, parlors, libraries, dens, bedrooms, sunrooms, recreation rooms, closets, hallways, laundry areas, and similar rooms/areas — NEC 210.12(A)
  • Kitchen branch circuits serving countertop outlets require AFCI protection in the 2023 NEC
  • Dormitory units — NEC 210.12(B)
  • AFCI protection is at the panel (combination AFCI breaker) or at the first outlet (AFCI outlet device) where permitted

Grounding and Bonding Checklist (NEC Article 250)

  • Grounding electrode system is complete — at minimum, a ground rod driven to 8 feet (or two rods if resistance exceeds 25Ω) per NEC 250.52 and 250.56
  • Ground rod connections are accessible or buried at least 6 inches below grade; connections use listed clamps per NEC 250.70
  • Water pipe used as a grounding electrode if metallic water pipe is available within 5 feet of building entry per NEC 250.52(A)(1)
  • Ground ring, concrete-encased electrode (UFER), or other electrodes bonded together with appropriate conductors per NEC 250.50
  • Main bonding jumper is installed in the main service panel connecting the neutral bar to the panel enclosure per NEC 250.28
  • Equipment grounding conductors are properly sized per NEC Table 250.122 and landed in the panel
  • Bonding jumpers are installed on bonded water piping per NEC 250.104(A) — applicable to metallic gas piping as well per 250.104(B)
  • Pool, spa, and hot tub bonding is complete and verified per NEC 680

Common Reasons Electrical Inspections Fail

Failure ReasonNEC ReferenceFix
Missing GFCI protection210.8Install GFCI receptacle or GFCI breaker at required locations
Missing AFCI protection210.12Replace standard breaker with combination AFCI breaker
Insufficient panel working clearance110.26Remove obstructions; relocate panel if necessary
Open knockouts in panel408.7Install filler plates in all unused openings
Unlabeled breakers408.4Complete and accurate circuit directory required
Exposed wiring in garage334.15Protect NM cable with conduit or use permitted wiring method
Neutral and ground bonded in sub-panel250.24Separate neutral bar and ground bar; remove bond jumper
Box fill overfill314.16Replace with larger box or split circuit into two boxes
Conductors too close to stud edge300.4Install nail plates to protect conductors
No arc flash label on 480V gear110.16Apply required arc flash warning label

Load Calculation Review

While most inspectors do not perform a full load calculation in the field, they may request the load calculation documentation for service entrance sizing. Key points:

  • General lighting load calculated at 3 VA per square foot for dwelling units per NEC 220.12
  • Small appliance branch circuits: 1,500 VA each, minimum two required per 220.52(A)
  • Laundry circuit: 1,500 VA minimum per 220.52(B)
  • Demand factors from Table 220.42 are applied to general lighting loads
  • Fixed appliances (water heater, disposal, dishwasher) added at nameplate value
  • HVAC: larger of heating or cooling load (they cannot operate simultaneously in most cases)
  • The calculated load must not exceed the service rating