NEC 90.13: correlation with OSHA

NEC 90.13 is short, but it matters. It points you to another rulebook that governs your work: OSHA 29 CFR 1910 Subpart S and 29 CFR 1926 Subpart K. The NEC tells you how to install. OSHA tells you how to work safely around it. Both apply on every job.

What NEC 90.13 actually says

Section 90.13 is an informational note added in the 2020 NEC cycle. It reminds users that OSHA standards in 29 CFR 1910 Subpart S (general industry) and 29 CFR 1926 Subpart K (construction) contain electrical safety requirements that correlate with the NEC. It is not enforceable code text. It is a pointer.

The distinction matters. The NEC is adopted by states and local AHJs as an installation standard. OSHA is federal law covering worker safety. An installation can be fully NEC compliant and still land you an OSHA citation if the work practice was wrong.

Field tip: when an inspector signs off on an install, that does not clear you with OSHA. Lockout/tagout, PPE, and approach boundaries are separate obligations.

Where NEC and OSHA overlap

OSHA's 1910.302 through 1910.308 (design safety standards) lift language almost verbatim from older NEC editions. OSHA has not fully updated to the current NEC, so you will see references that trace back to the 1978 through 2007 cycles depending on the subsection.

On construction sites, 29 CFR 1926.402 through 1926.408 cover the same territory. Grounding, GFCI protection for receptacles used by employees, temporary wiring, and guarding of live parts all show up in both books with similar but not identical language.

• Grounding: NEC Article 250 correlates with 1910.304(g) and 1926.404(f).
• GFCI on construction sites: NEC 590.6 correlates with 1926.404(b)(1).
• Working space: NEC 110.26 correlates with 1910.303(g).
• Guarding live parts: NEC 110.27 correlates with 1910.303(g)(2).
• Flexible cords: NEC Article 400 correlates with 1910.305(g) and 1926.405(g).

Work practices: where OSHA goes beyond NEC

NFPA 70E is the bridge. OSHA does not write the shock and arc flash boundary tables itself, but it enforces the general duty clause and 1910.333 by pointing to consensus standards. 70E is the one OSHA recognizes in practice. If you work energized, you work to 70E.

Key areas where OSHA requires more than the NEC installation rules:

1. Lockout/tagout procedures under 1910.147 and 1910.333(b).
2. Qualified person training and documentation under 1910.332.
3. Arc flash PPE selection, tied to incident energy analysis or the 70E category tables.
4. Approach boundaries for unqualified and qualified persons under 1910.333(c).
5. Energized work permits when de-energizing is not feasible.

Temporary power and the construction trap

Temporary wiring on a construction site is where NEC Article 590 and OSHA 1926.404/405 most often collide in the field. The NEC lets you do things on a temp install that would fail a permanent inspection. OSHA still expects GFCI protection on every 15, 20, and 30 amp 125-volt receptacle used by employees, or an assured equipment grounding conductor program under 1926.404(b)(1)(iii).

Most contractors pick GFCI. The AEGCP is paperwork heavy: written procedure, competent person designated, testing before first use and every three months, documented continuity and terminal tests on every cord and tool. Skip a test cycle and you lose the program.

Field tip: if your GFCI keeps tripping on a long cord run, do not swap to a non-GFCI receptacle. Shorten the run, check for damaged insulation, or use a GFCI at the tool end. The trip is telling you something.

Inspections, citations, and who enforces what

AHJs enforce the NEC at permit and final. OSHA compliance officers enforce work practices during and after construction. A foreman who energizes a panel without a permit, without PPE, and without a qualified second person is looking at a serious or willful citation regardless of whether the panel itself meets Article 408.

Citations typically cluster in a few places: missing GFCI on temp power, damaged extension cords in service, open knockouts and unguarded live parts in gear rooms, and working space blocked by stored material. These are all NEC issues that become OSHA issues the moment an employee is exposed.

How to use 90.13 on the job

Treat the informational note as a reminder to check two books, not one. When you plan a job, walk the install rules in the NEC and the work rules in NFPA 70E and the relevant OSHA subpart. The install rules tell you what to build. The work rules tell you how to stay alive while building it and how to service it five years later.

For service and maintenance work on existing gear, 70E and 1910 Subpart S are the primary references. For new construction, 70E and 1926 Subpart K control the work. In both cases, the NEC is the installation backbone and 90.13 is the breadcrumb that tells you to keep reading.

• Before energized work: job briefing, permit if required, PPE rated to the incident energy.
• Before any work: verify absence of voltage with a tested meter on a known source before and after.
• On temp power: GFCI on every applicable receptacle, inspect cords daily.
• On permanent installs: 110.26 working space kept clear, 110.27 guarding intact.