NEC 90.12: rough-in checklist

NEC 90.12 landed in the 2023 code cycle and pulled a long-standing jobsite expectation into enforceable text: protect wiring and equipment from damage and contamination during and after installation. It's short, but inspectors are citing it, and GCs are starting to reference it when rough-in gets sloppy. Here's what to actually do on site.

What 90.12 Says

The exact language: "Installed electrical equipment and wiring shall be protected against damage and contamination during and after installation." That's it. No tables, no exceptions, no subsections. The brevity is the problem. It's written broadly so the AHJ can cite it any time moisture, debris, concrete splatter, drywall dust, or physical impact compromises your install.

Pair 90.12 with the specific protection articles already in force: 300.4 for physical damage, 300.5(F) for underground, 300.6 for corrosion, 312.7 and 314.23 for box integrity, and 110.11/110.12 for deteriorating agents and mechanical execution. 90.12 is the umbrella. The specific articles are where you'll actually hang your defense during an inspection.

Pre Rough-In Walkthrough

Before you pull a single wire, walk the space with the other trades' schedule in hand. You're looking for anything that will spray, grind, cut, or drop after you leave. HVAC sheet metal crews, fire sprinkler fitters, and drywall tapers cause the most post-rough damage. Plan your cable routing to stay out of their working envelope where possible.

Mark your conductor paths on the studs with keel or a crayon before drilling. Shallow bores and off-center holes are the number one source of drywall screw punctures. NEC 300.4(A)(1) requires 1-1/4 in. from the nearest edge, or a 1/16 in. steel plate. Plates are cheap insurance, not a shortcut.

If the framer didn't leave you a clean path, install nail plates even where you technically meet the 1-1/4 in. rule. A $0.40 plate beats an open wall and a callback every time.

Cable and Raceway Protection

Once pulled, conductors are exposed to three things: impact, moisture, and contamination. Address all three before you leave the rough.

• Cap open raceway ends with manufactured plugs or duct seal. Dust and mortar in a conduit will destroy a fish tape and contaminate insulation.
• Bundle NM cable away from plumbing rough and gas lines. A pipe wrench swing breaks staples and nicks jackets.
• Keep cable jackets at least 6 in. inside boxes where possible, even though 312.5(C) and 314.17(B) only require the jacket to extend 1/4 in. into the box. Extra slack lets you re-dress damaged sections without a splice.
• Any conductor passing through a metal stud needs a listed bushing per 300.4(B)(1). Grommets pop out under pull tension. Snap-in bushings stay put.

Where cable runs through areas with ongoing trade work, sleeve vulnerable sections in scrap EMT or flex. It's not required by code, but it's defensible under 90.12 and stops the mystery staple gun from a finish carpenter.

Box and Device Protection

Boxes are a contamination magnet. Drywall mud, texture spray, and concrete pour spatter will coat terminals, clog KOs, and corrode ground screws. Taping boxes over during rough-in is standard practice, and 90.12 now gives it teeth.

Use painter's tape or manufactured box covers. Avoid duct tape, which leaves adhesive residue on plaster ears and device yokes. For deep wall boxes near a stucco or exterior pour, foam backer or a plastic cover plate screwed to the mud ring keeps everything out until trim.

Red-tag risk: a panelboard interior left open during a ceiling grid install. One tile crew's metal shavings on a bus bar, and you're replacing the guts. Cover gear the day you set it.

Panelboards, Gear, and Terminations

Article 110.12(A) already requires "unused openings" to be closed and explicitly calls out keeping foreign materials out of equipment during construction. 90.12 reinforces it. If you set a panel, load center, or transformer before the space is dried in, bag it. Heavy-mil poly and tape around the cabinet, not just a cardboard sheet on top. Moisture drifts sideways.

Torque values on lugs are a protection issue too. Per 110.14(D), terminations must be torqued per manufacturer specs. Documented torque with a calibrated driver protects against heat damage that 90.12 implicitly covers. Log your values.

• Bag or shrink-wrap all panelboards, switchboards, and MCCs until energization.
• Close unused KOs with listed plugs, not tape or duct seal alone (110.12(A)).
• Protect bus stabs with the shipping covers until breakers are installed.
• Elevate floor-mounted gear off slabs if concrete is still curing. Moisture wicks.

Rough-In Inspection Checklist

Run this the morning of your inspection. Fix anything that fails before the AHJ shows up.

1. All NM and AC cable within 1-1/4 in. of stud edge has a nail plate (300.4(A)(1)).
2. Cable jackets extend into boxes per 314.17(B); no nicks or crushed sections visible.
3. Conductor bundles supported within 12 in. of each box and every 4-1/2 ft (334.30).
4. All open conduit ends capped; pull strings intact and dry.
5. Grounding conductors pig-tailed and folded into boxes, not dangling.
6. Boxes taped or covered; no mud, texture, or dust inside.
7. Panelboards bagged if drywall or finishes are pending.
8. Unused KOs plugged on any exposed enclosure.
9. Nothing stored on top of or leaning against gear.
10. Photos taken of protected-but-concealed runs (plates, sleeves) for your own record.

90.12 is broad on purpose. Treat it as the reason you already do this work right, and document enough that an inspector citing it walks away satisfied on the first pass.