1910.305(a)(1): Bonding Metal Parts and Wiring in Ducts
Metal raceways, cable trays, enclosures and other metal parts serving as grounding conductors must be effectively bonded for continuity and to carry fault current safely, with nonconductive coatings removed at contact points. Isolating fittings for noise reduction need an internal grounding conductor. No wiring may run in ducts carrying dust, loose stock, flammable vapors or cooking ventilation.
Key takeaways
- 1910.305(a)(1) is part of OSHA's general industry standards (29 CFR Part 1910, Subpart S).
- OSHA cited it 19 times in the last 3 years, in 19 inspections, with $70,940 in current penalties.
- Most citations: MI (4), OK (3), IN (2).
- Related part: 1910.305(a) Wiring methods (382 citations).
- Free 5-minute toolbox talk for your crew below.
In this article
What this rule covers
29 CFR 1910.305(a)(1) ("General requirements") is one requirement inside 1910.305 Wiring methods, components, and equipment for general use, an OSHA general industry standard (Part 1910, Subpart S). It includes 3 sub-paragraphs. The official text below is copied word for word from the Electronic Code of Federal Regulations (eCFR). The numbers, injury cases and training on this page show how OSHA enforces it on real job sites.
Official text
(1) General requirements. 19 citations
(i) Metal raceways, cable trays, cable armor, cable sheath, enclosures, frames, fittings, and other metal noncurrent-carrying parts that are to serve as grounding conductors, with or without the use of supplementary equipment grounding conductors, shall be effectively bonded where necessary to ensure electrical continuity and the capacity to conduct safely any fault current likely to be imposed on them. Any nonconductive paint, enamel, or similar coating shall be removed at threads, contact points, and contact surfaces or be connected by means of fittings designed so as to make such removal unnecessary. Open (a)(1)(i) 19 citations
(ii) Where necessary for the reduction of electrical noise (electromagnetic interference) of the grounding circuit, an equipment enclosure supplied by a branch circuit may be isolated from a raceway containing circuits supplying only that equipment by one or more listed nonmetallic raceway fittings located at the point of attachment of the raceway to the equipment enclosure. The metal raceway shall be supplemented by an internal insulated equipment grounding conductor installed to ground the equipment enclosure.
(iii) No wiring systems of any type may be installed in ducts used to transport dust, loose stock, or flammable vapors. No wiring system of any type may be installed in any duct used for vapor removal or for ventilation of commercial-type cooking equipment, or in any shaft containing only such ducts.
Source: eCFR, text current as of 2026-10-15. Read all of 1910.305.
Where and how often it was cited
| Year | Citations |
|---|---|
| 2023 | 4 |
| 2024 | 7 |
| 2025 | 7 |
| 2026 | 1 |
Top states: MI (4), OK (3), IN (2), KS (2), TX (2)
Largest penalties
| Employer | Location | Penalty for this rule |
|---|---|---|
| ACME BRICK CO | TULSA, OK | $21,279 |
| TRIUMPH FOODS, LLC | SAINT JOSEPH, MO | $12,059 |
| AMERICAN SUGAR REFINING INC | ARABI, LA | $9,598 |
| PREMIUM VELOCITY AUTO LLC | LEAGUE CITY, TX | $6,084 |
| 157903 - TRUE2FORM COLLISION REPAIR CENTERS, LLC | GARNER, NC | $5,850 |
Free toolbox talk
A 5-minute crew talk on 1910.305(a)(1), plus alerts when this rule changes. Free.
OSHA interpretation letters
None exist. OSHA has not published a letter of interpretation for 1910.305(a)(1).
Related parts of this rule
- 1910.305(a) Wiring methods 382 citations
- 1910.305(a)(2) Temporary wiring 358 citations
- 1910.305(a)(2)(x) 123 citations
- 1910.305(a)(2)(ix) 100 citations
- 1910.305(a)(2)(i) 77 citations
- 1910.305(a)(2)(ii) 27 citations
- 1910.305(a)(1)(i) 19 citations
- 1910.305(a)(2)(xi) 11 citations
- 1910.305(a)(2)(i)(B) 10 citations
- 1910.305(a)(2)(v) 8 citations
- 1910.305(a)(2)(v)(C) 8 citations
- 1910.305(a)(3) Cable trays
Get your crew competent
Trainers on Black Belt Safety: Marc Harvey, Dana Reyes
Trainers and suppliers: feature your business on this rule for $25/month.
Frequently asked questions
Why remove paint at fittings?
Nonconductive paint, enamel or coatings must be removed at threads and contact surfaces, or suitable fittings used, so bonding is effective.
Can wiring run inside a dust duct?
No. No wiring system may be installed in ducts used to transport dust, loose stock or flammable vapors.
What about kitchen exhaust ducts?
No wiring may be installed in ducts for vapor removal or ventilation of commercial-type cooking equipment, or in shafts containing only such ducts.
About this page
Sources
- 29 CFR 1910.305 (eCFR), text current as of 2026-10-15
- U.S. Department of Labor enforcement data: OSHA inspections, citations and accident records, copied nightly; data as of 2026-10-20
3-year window. Federal OSHA only; state-plan rules are not counted. Plain-language text is a summary, not legal advice; the official text controls. Black Belt Safety is not part of OSHA or the Department of Labor.