Arc flash safety: what OSHA requires
Published 2026-10-18 · 9 min read · sources checked 2026-10-18
There is no single OSHA standard called “arc flash”. The duties are spread across three places, and which one binds you depends on what you are building. What does not change: deenergized and locked out is the control, and arc-rated clothing is what is left when you cannot get there.
What an arc flash is
OSHA describes an electric arc as a type of electrical explosion: a bright flash of hot gas that can exceed 35,000 °F, vaporising the conductor metal and producing a blast with deafening noise, concussive force and super-heated shrapnel. Three of OSHA’s own points are worth putting on a toolbox talk sheet:
- Low voltage is not low risk. Even 120/208 V can create arcs energetic enough to burn skin and ignite clothing. Incident energy depends mostly on amperage, clearing time and distance — not voltage.
- Most arc flash burns come from clothing that ignites, not from the arc itself.
- “Deenergized” is often wrong. Parts that have been deenergized but not locked out or tagged are treated as energized.
Where the OSHA duties live
| Work | Rule | What it requires |
|---|---|---|
| General construction electrical work | 1926.416(a)(1) | No work close enough to contact a power circuit unless it is deenergized and grounded, or effectively guarded |
| Deenergized circuits on a construction site | 1926.417 | Rendered inoperative and tagged at every point where they can be energized |
| Building or altering transmission and distribution lines | 1926.960(g) | Hazard assessment, incident-energy estimate, clothing and arc-rating rules |
| General industry (facility maintenance) | 1910.333 · 1910.269 | Lockout/tagout before work is treated as deenergized; power-generation work mirrors Subpart V |
Read from 29 CFR 1926 Subparts K and V on 2026-10-18; the 1910 rows as summarised on OSHA’s arc flash page.
For most contractors that means the first two rows. Subpart K does not prescribe arc-rated clothing; it prescribes not working on live circuits. Put the isolation in a written lockout/tagout procedure and see lockout/tagout requirements for the program around it.
The power-line rule, step by step
Subpart V covers the construction of electric power transmission and distribution lines and equipment, including altering and improving existing lines. Its arc-flash paragraph is the most specific in the construction standards:
| 1926.960 | Step | Duty |
|---|---|---|
| (g)(1) | Assess | Identify employees exposed to hazards from flames or electric arcs |
| (g)(2) | Estimate | Make a reasonable estimate of the incident heat energy for each exposed employee |
| (g)(3) | Ban | No clothing that could melt onto skin or ignite and keep burning |
| (g)(4) | Flame-resistant outer layer | Over 600 V contact, ignition risks, or an estimate above 2.0 cal/cm² |
| (g)(5) | Arc rating ≥ estimate | Whole-body arc-rated protection whenever the estimate exceeds 2.0 cal/cm², with limited hand, foot and head exceptions |
The estimate does not have to be done task by task. The rule’s own note allows broad estimates covering several system areas, provided they represent the maximum exposure for those areas, and it deems employers who follow the method in Appendix E to Subpart V to be in compliance.
Clothing: what is banned, what is required
The ban comes first. Under 1926.960(g)(3) an exposed employee may not wear clothing that could melt onto the skin or ignite and keep burning. The rule’s note names the fabrics: acetate, nylon, polyester, rayon and polypropylene, alone or in blends — unless treated, or worn so as to eliminate the hazard. OSHA adds that meltable undergarments are dangerous under an arc-rated outer layer, and that an untucked shirt or rolled-up sleeve defeats it.
Above 2.0 cal/cm², arc-rated protection covers the whole body. The exceptions are narrow: hands in rubber insulating gloves with protectors (or heavy-duty leather gloves up to 14 cal/cm²), feet in heavy-duty work boots, and the head where a helmet meeting the electrical clause of 1926.100(b)(2) — see hard hat requirements — and, at higher levels, an arc-rated faceshield fall within the limits in (g)(5)(iii)–(v).
Danger
Where NFPA 70E fits
NFPA 70E, Standard for Electrical Safety in the Workplace, is a national consensus standard, not an OSHA regulation — OSHA lists it under consensus standards with that exact note. OSHA’s arc flash page describes it as originally developed at OSHA’s request and as helping employers comply with 1910 Subpart S and 1926 Subpart K. NFPA offers it free to read with an account.
In OSHA’s words it sets requirements for safe work practices that help avoid injuries from shock, electrocution, arc flash and arc blast — which makes it the natural reference when your program has to decide how energized work is justified, permitted and protected. Electrocution is one of the focus four; arc flash is the electrical hazard that hurts the people who believed the panel was dead.
The rule text
Quoted from the current eCFR text of title 29, read on 2026-10-18; “…” marks text left out.
No employer shall permit an employee to work in such proximity to any part of an electric power circuit that the employee could contact the electric power circuit in the course of work, unless the employee is protected against electric shock by deenergizing the circuit and grounding it or by guarding it effectively by insulation or other means.
Equipment or circuits that are deenergized shall be rendered inoperative and shall have tags attached at all points where such equipment or circuits can be energized.
For each employee exposed to hazards from electric arcs, the employer shall make a reasonable estimate of the incident heat energy to which the employee would be exposed.
The employer shall ensure that each employee exposed to hazards from electric arcs wears protective clothing and other protective equipment with an arc rating greater than or equal to the heat energy estimated under paragraph (g)(2) of this section whenever that estimate exceeds 2.0 cal/cm². This protective equipment shall cover the employee’s entire body, except as follows: …
Sources, with the date each was read
- Electric-Arc Flash Hazards (OSHA)read 2026-10-18
- Electrical — Standards, incl. national consensus standards (OSHA)read 2026-10-18
- 29 CFR 1926.960 — Working on or near exposed energized parts (eCFR)read 2026-10-18
- 29 CFR 1926.950 — Subpart V scope (eCFR)read 2026-10-18
- 29 CFR 1926.416 and 1926.417 — Electrical safety-related work practices (eCFR)read 2026-10-18