Rough-In Inspection Readiness

Purpose

Turn the rough-in inspection into a formality by running the inspector's own checks the day before, while everything is still reachable. Every item an inspector fails a rough-in on is measurable before they arrive, and every one of them costs an order of magnitude more to fix after the drywall than before it.

The re-inspection is not the real cost. The real cost is the schedule: a failed rough holds the insulator, who holds the drywaller, who holds every trade behind them, and the general contractor remembers which subcontractor caused it long after the correction is forgotten. A shop that self-inspects is a shop that gets called back.

Scope

Covers the pre-inspection self-check on a residential or light-commercial rough-in: box installation and fill, cable support and protection, conductor lengths, grounding, panel work, and the paperwork on site.

Does not cover the design itself, meaning the load calculation, circuit count and receptacle layout, which are set at permit; the final or trim inspection, where device installation, GFCI and AFCI function testing and cover plates are the subject; or low-voltage and fire alarm rough-in, which are usually a separate permit and a separate inspector.

Roles and handoffs

Procedure

1. Confirm the permit is issued, posted and matches the work you actually installed. Check the permit card is on site and visible, that the approved plans on site are the current revision, and that any field changes have been dealt with the way the authority having jurisdiction requires. Acceptance: card posted, plan revision on site matching the revision the office holds, change log current. Wrong looks like a crew rough-ing to a revision the plan reviewer never saw. Stop rule: an undocumented field change is corrected on paper before the inspection, not explained at the panel, because an inspector who finds an unapproved change stops reading and starts looking.

2. Verify box fill on every box carrying more than two cables, by counting rather than by feel. Add the volume allowances the NEC assigns: one for each current-carrying conductor by its size, one allowance of the largest equipment grounding conductor for all the grounds together, one for all internal cable clamps of the largest conductor size, and two allowances of the largest conductor connected to a device for each device yoke. Compare the total to the box's marked volume plus the marked volume of any plaster ring. Acceptance: required volume at or below available volume, computed and written for each such box. Wrong looks like conductors that will not fold back without forcing. Stop rule: a box that fails gets changed now, while the framing is open, because the same change after drywall is a repair to the wall as well as to the box.

3. Check cable support and the sheath entry at every box, walking the run rather than spot-checking. Nonmetallic-sheathed cable is secured within 12 in of a box with a cable clamp and at intervals not exceeding 4.5 ft along the run, and where a box has an internal clamp the sheath extends at least 1/4 in inside the box. Acceptance: every run correct, with staples driven flat and not cutting the sheath. Wrong looks like a staple hammered until it bites, which is a conductor fault waiting for the drywall screw that finishes it. Stop rule: a cut or crushed sheath is replaced, not taped, and the replacement is logged so the inspector sees the same thing you did.

4. Walk every framing member the cable passes through for the protection the code requires. Where a cable is closer than 1-1/4 in from the nearest edge of a stud, joist or plate, it takes a steel plate at least 1/16 in thick, and a bored hole in the center of a nominal two-inch stud usually clears without one. Acceptance: every hole and notch inside the depth limit measured, and every one within 1-1/4 in of an edge plated. Wrong looks like a plate on a notch and none on the plate bore beside it. Hazard clause: check for holes drilled through the plate by other trades while you look, because a cable sharing a bore with a plumbing line or a gas line is a hazard that outlives this inspection.

5. Measure conductor length at every outlet before you cap anything. At each box, at least 6 in of free conductor is required, measured from where it emerges from the cable sheath, with at least 3 in of that extending outside the box opening. Acceptance: 6 in and 3 in met at every box, checked with a tape on any box you are unsure of rather than by eye. Wrong looks like a box where a device could be landed but not folded back. Stop rule: short conductors are the one rough-in defect that gets discovered at trim, by a different tech, on a different day, and it is fixed now by adding an accessible junction with a cover, not by stretching.

6. Set box depth and alignment against the finished surface, not the framing. Boxes set in walls of noncombustible material may be set back no more than 1/4 in from the finished surface, and boxes in combustible material must be flush with or project from that surface. Work out the finished thickness including any tile or panelling the plan calls for. Acceptance: each box measured against the stated finished thickness, and the finished thickness written on the check sheet. Wrong looks like boxes set for 1/2 in drywall in a room getting 5/8 in with a tile backsplash. Stop rule: correct depth now with the right box or an extension ring; an extension ring added at trim is a callback the customer sees.

7. Verify grounding and panel work is complete to the point the inspection covers. Every box, device yoke and metal enclosure has its grounding conductor made up and long enough to land, the panel's grounds and neutrals are landed on their correct bars with one conductor per terminal unless the bar is listed for more, and the grounding electrode conductor and its connections are complete and accessible. Acceptance: every one of those confirmed with the deadfront off. Wrong looks like two neutrals under one screw on a bar listed for one. Hazard clause: if the service is already energized, isolate and prove dead live-dead-live per NFPA 70E-2021, 120.5, and lock and tag under 29 CFR 1910.333(b)(2) before the deadfront comes off; a panel with a live service and no main installed is the most dangerous enclosure on the job.

8. Walk the job as the inspector will, then produce a correction list with a location on every line. Start at the service, work through the panel, then room by room in the order the plan is numbered. Acceptance: a written list where each item names the specific box, run or panel position, so the crew can find it without the lead. Wrong looks like "box fill in the kitchen." Stop rule: the inspection is not called until every line on that list is signed off by the person who corrected it, because a correction reported as done without a name is the one that turns out not to be.

When the site does not match the assumption

Another trade has damaged your work, usually a plumber's hole through a cable or a framer's screw into a box. Photograph it before you touch it, repair it, and report it through the general contractor the same day. The repair is yours; the cost conversation belongs to the office and the general contractor, not to two techs in a hallway.

The inspection is called and the job is not ready because the schedule moved. Say so and move it. Inspectors keep a longer memory of which contractors waste their trip than of which ones rescheduled.

The plan is silent on something the field must decide, such as an outlet location a cabinet run now blocks. Do not decide it alone on the day. Get it in writing from the general contractor or the designer, attach it to the permit file, and install to the written answer.

The record this produces

One rough-in check sheet per permit: the permit number, plan revision and inspection date; the box-fill computation for every box carrying more than two cables, showing the allowances counted and the marked box and ring volumes; the finished-wall thickness the box depths were set to; the support and protection walk noted by run; a conductor-length confirmation per room; the panel and grounding confirmation; the correction list with a location and the initials of whoever cleared each line; and the inspection result with any inspector comment recorded verbatim.

The lead reads the check sheet the morning of. The office reads the inspector's comments to spot a pattern across jobs, which is how a shop finds out that one crew is consistently short on conductor length. And the box-fill computations are what you hand an inspector who questions a box, which turns an argument into a document.

Worked pass: three-bedroom addition, rough-in the day before inspection

Step 1: permit posted, plans on site are revision B, and the office confirms revision B is what was reviewed. One field change, an added receptacle on the rear wall, is already logged.

Step 2 fails on the kitchen switch bank. The box is a 4 in by 4 in by 1-1/2 in square, marked 21.0 cubic inches, with a raised device ring marked 3.0 cubic inches, giving 24.0 available. Into it come four 12/2 cables plus one device yoke, with internal clamps. The count: eight current-carrying 12 AWG conductors at 2.25 cubic inches each is 18.0; all the equipment grounding conductors together count as one 12 AWG allowance, 2.25; the internal clamps together count as one, 2.25; the single device yoke counts as two, 4.5. Total required is 27.0 against 24.0 available, so the box is over by 3.0 cubic inches.

Stop rule taken. The box is swapped for a 4 in by 4 in by 2-1/8 in square marked 30.3 cubic inches, which with the same 3.0 cubic inch ring gives 33.3 available against the same 27.0 required, clearing by 6.3. The swap takes eleven minutes with the framing open. The same swap after drywall is a hole cut, a box changed, a patch and a paint call, on a wall the homeowner is watching.

Steps 3 and 4: eleven runs walked. Two staples in the hall are backed off a sixteenth where they were driven proud. Three bores in the top plate over the bathroom sit inside 1-1/4 in of the edge and take steel plates.

Step 5: conductor lengths confirmed at 34 boxes. One box in the mechanical room measures 5 in of free conductor because the cable was cut short at a re-route; it gets an accessible junction box with a blank cover rather than a stretch, and the junction location goes on the check sheet so the trim tech is not surprised.

Step 6: the plan calls for 5/8 in drywall throughout with tile only in the bath. Nine boxes in the bath were set for 1/2 in and are re-set before the walk finishes.

Step 7: panel confirmed with the deadfront off, service not yet energized, one doubled neutral corrected on a bar listed for one conductor per terminal.

Step 8: the correction list runs to sixteen items with a location on each. Fifteen are cleared and initialled that afternoon. The sixteenth, a plumber's bore through a bedroom cable, is photographed, repaired, and reported through the general contractor the same day. The inspection is called for the following morning and passes with no corrections, which is the outcome the three hours of self-checking bought.

References

• NEC Article 314, in the edition your authority having jurisdiction has adopted, for box volume calculations, conductor allowances and box depth relative to the finished surface
• NEC Article 300 for free-conductor length at outlets and for protection of cables from physical damage at framing members, and NEC Article 334 for support and securing of nonmetallic-sheathed cable
• NEC Article 250 for grounding and bonding of boxes, enclosures and device yokes, and the panelboard's own listing for the number of conductors permitted per terminal
• 29 CFR 1910.333(b)(2) and NFPA 70E-2021, 120.5, in the edition your employer's electrical safety program has adopted, for isolation and the live-dead-live sequence in step 7
• See related: Panel Labeling and As-Built Handover SOP, Grounding and Bonding Verification SOP