A rough-in electrical inspection is the code check a local inspector performs after all wiring, boxes, and grounding are installed but before insulation or drywall covers them. Every jurisdiction in the United States enforces some version of the National Electrical Code, and this is the only realistic chance anyone has to physically trace each wire and connection before the walls close. Pass it and you can insulate and sheetrock. Fail it, or skip it, and the fixes get expensive fast.
When to Schedule It
The window opens once framing is complete and the building is weathertight, and it closes the moment anything starts covering the wiring. By that point, every cable run, junction box, and grounding conductor should be installed, secured, and fully visible. Nothing is energized. The system sits exposed and inert so the inspector can see every path and connection.
Electrical rough-in is typically the last of the mechanical trades to install, since cable is flexible enough to route around plumbing and ductwork. In practice the trades overlap, but the general sequence puts electricians working after plumbers and HVAC crews have claimed the big cavities.
Do not cover any wiring before the inspector signs off. Jurisdictions typically hold whoever concealed the wiring responsible for the full cost of opening it back up, and no inspector will approve work they cannot see.
Permit and Site Access
You need an electrical permit from your local building department before any inspection can be scheduled. Without one, the work is unauthorized. Fees vary with the scope: small residential jobs may run under $100, while larger or commercial projects can reach several hundred. Post the permit on site, usually near the main panel, so the inspector can sign it.
Site prep matters more than people expect. The inspector needs unobstructed access to every box, every cable run, and the service panel. Clear construction debris, move ladders and stacked materials away from the walls, and keep crawl space and attic hatches reachable. If your jurisdiction requires a circuit directory or wiring diagram, attach it to the panel enclosure before the visit so the inspector can match the physical installation against the approved plans.
What the Inspector Checks
The inspection is methodical. The inspector walks every room, traces wiring paths, tugs on cables, measures distances, and checks each component against the NEC edition your jurisdiction has adopted. All 50 states enforce some version of the code, though the specific edition varies by state.1NFPA. Learn Where the NEC Is Enforced The edition in force determines which specific requirements apply, but the core items below have been consistent across recent editions.
Cable Routing and Support
Every nonmetallic-sheathed cable (standard Romex-type wire) must be stapled or strapped within 12 inches of entering any electrical box and at intervals no greater than 4½ feet along the run. Inspectors check this with a tape measure. It is one of the most commonly flagged violations because the work is tedious and often rushed.
Where cables pass through holes drilled in wood studs or joists, the edge of the hole must sit at least 1¼ inches from the nearest edge of the framing member. If the hole is closer than that, a steel nail plate at least 1/16 inch thick must cover the area so a future drywall screw or finish nail cannot puncture the wire. Inspectors look carefully for these plates. A missed one can mean a fire years after the walls close.
Each box must have at least 6 inches of free conductor extending from it, with a minimum of 3 inches projecting outside the box opening. Short leads get failed.
Boxes and Box Fill
Box fill is where many installations run into trouble. The NEC assigns a specific volume allowance in cubic inches for every conductor, clamp, device, and grounding wire inside a box. A standard single-gang plastic box might hold four or five 14-gauge wires before it exceeds its rated volume. One extra wire creates a heat buildup risk the inspector will catch. The fix is swapping in a deeper or larger box, which is far easier before drywall.
Metal boxes carry an extra requirement: the equipment grounding conductor must bond directly to the box through a connection dedicated to that purpose, such as a green grounding screw or a listed grounding clip. The connection cannot share a screw that also holds the receptacle, because removing the receptacle would otherwise sever the safety path.
Box setback is also checked. In noncombustible wall finishes like drywall, the front edge of the box may sit up to ¼ inch behind the finished surface. In combustible surfaces like wood paneling, the box must be flush with or project beyond the surface. Inspectors check depth against the expected wall thickness at rough-in because a box set too deep is expensive to correct later.
Where a ceiling fan could be mounted, even if none is planned now, a fan-rated box must be installed. Standard ceiling boxes are not designed for the dynamic load of a spinning fan, and inspectors specifically look for this.
AFCI and GFCI Protection
Arc-fault circuit interrupters are required on virtually every living-space circuit. The current NEC requires AFCI protection for all 120-volt, 15- and 20-amp branch circuits serving bedrooms, living rooms, dining rooms, kitchens, family rooms, hallways, closets, laundry areas, and similar spaces. At rough-in, the inspector confirms AFCI breakers are specified for these circuits or that the panel is set up to accept them.
Ground-fault circuit interrupters are required wherever water and electricity might meet: bathrooms, kitchen countertop receptacles, garages, outdoor locations, unfinished basements, crawl spaces, laundry areas, and any receptacle within six feet of a sink or bathtub. Protection can come from a GFCI breaker in the panel or a GFCI receptacle at the first outlet on the circuit. The devices themselves are usually installed later, but the protection plan is verified at rough-in.
Wire Sizing
Every wire must be thick enough for the breaker protecting it. The NEC limits overcurrent protection to 15 amps for 14-gauge wire, 20 amps for 12-gauge, and 30 amps for 10-gauge. A 14-gauge wire on a 20-amp breaker can overheat before the breaker trips. It is an automatic failure, and inspectors trace wire sizes back to the panel to confirm the matchups.
Common Reasons Rough-Ins Fail
Most failures cluster in a few predictable categories. Working through this list before you call for the inspection usually saves a re-inspection fee and a week of delay.
- Missing nail plates where cables run within 1¼ inches of a framing edge.
- Unsupported cables running loose between studs without staples at the required intervals.
- Overcrowded boxes with too many conductors or splices for the rated volume.
- Missing AFCI or GFCI protection on circuits that require it.
- Double-tapped breakers, with two wires landed on a single breaker terminal designed for one.
- Wrong wire gauge for the breaker, such as 14-gauge on a 20-amp circuit.
- Short conductor leads: less than 6 inches of free wire at a box, or less than 3 inches past the opening.
- Unused box knockouts left open. Plastic boxes with punched-out but unused cable entries need to be replaced entirely.
None of these are hard to fix while the walls are open. All of them get harder once insulation and drywall go up.
The Inspection Visit
Most building departments require 24 to 48 hours of advance notice. Some offer online scheduling; others still take requests by phone. The visit itself is usually brief, 30 minutes to an hour for a standard residential project, but the inspector covers a lot of ground.
Expect the inspector to walk every room, tug cables to confirm they are secured, measure conductor lengths, examine box fill, verify grounding connections, and check nail plate placement against the approved plans and permit scope. Problems get called out on the spot and noted on the inspection report.
Results come immediately. A pass is marked with a green tag, an approval sticker on the permit card, or the inspector’s signature on the permit, depending on the jurisdiction. That signature is what authorizes you to close the walls.
After a Pass or a Fail
A passing rough-in clears the way for insulation, vapor barriers, and drywall. It covers only the hidden infrastructure. A separate final electrical inspection happens later, after switches, receptacles, light fixtures, and cover plates are installed and the system is energized. At that final visit, the inspector tests outlets, turns on lights, and verifies the completed system works as designed. Utilities generally will not release permanent power to a new construction project without proof that the required electrical inspections have been completed and approved; typically the contractor or homeowner provides a signed inspection form before service is energized.
A failed rough-in produces a correction notice listing each specific violation. Fix the items, then call the building department to schedule a re-inspection. Re-inspection fees are common and add up quickly if you fail more than once. Nothing moves forward until every item on the notice is resolved and the inspector signs off. The walls stay open the whole time.
Why Skipping the Permit and Inspection Backfires
Some homeowners are tempted to skip the permit entirely to save money or avoid the paperwork. The consequences usually surface at the worst possible times.
Building departments in most jurisdictions impose surcharges for work started without a permit, commonly double the original permit fee and sometimes higher. The department can also require you to open finished walls so the wiring can be inspected, at your expense.
Insurance is the bigger exposure. If property damage traces back to unpermitted electrical work, say a fire in an unpermitted addition, the insurer may deny the claim on the grounds that the work was never inspected or verified to meet code. Some carriers exclude coverage entirely for portions of a home with known unpermitted work, and discovery during a claims investigation can lead to policy cancellation or non-renewal.
Unpermitted wiring also creates problems at resale. Home inspectors routinely flag signs of DIY or unpermitted work, and once buyers see that flag, they demand repairs, renegotiate the price, or walk away. In many states, sellers face legal liability for failing to disclose known unpermitted work, and courts have held sellers responsible even when they claimed they didn’t know.
Compared with the cost of a permit and an hour of the inspector’s time, these risks are disproportionate. The rough-in inspection exists to catch problems while they are still cheap and simple. Skipping it just moves those problems to a point when they are neither.