1910.304(f)(1): Overcurrent Protection for 600 Volts or Less
For circuits rated 600 volts, nominal, or less, employers must protect conductors and equipment from overcurrent according to their ability to safely carry current. Overcurrent devices must be readily accessible and kept away from physical damage and easily ignitable material, disconnecting means are required ahead of certain fuses, and fuses and breakers must be located or shielded so their operation does not burn or strike workers.
Key takeaways
- 1910.304(f)(1) is part of OSHA's general industry standards (29 CFR Part 1910, Subpart S).
- OSHA cited it 136 times in the last 3 years, in 136 inspections, with $197,006 in current penalties.
- Most citations: NY (25), VA (23), HI (18).
- Related part: 1910.304(f) Overcurrent protection (136 citations).
- Free 5-minute toolbox talk for your crew below.
In this article
What this rule covers
29 CFR 1910.304(f)(1) ("600 volts, nominal, or less") is one requirement inside 1910.304 Wiring design and protection, an OSHA general industry standard (Part 1910, Subpart S). It includes 9 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) 600 volts, nominal, or less. The following requirements apply to overcurrent protection of circuits rated 600 volts, nominal, or less. 136 citations
(i) Conductors and equipment shall be protected from overcurrent in accordance with their ability to safely conduct current. 2 citations
(ii) Except for motor running overload protection, overcurrent devices may not interrupt the continuity of the grounded conductor unless all conductors of the circuit are opened simultaneously.
(iii) A disconnecting means shall be provided on the supply side of all fuses in circuits over 150 volts to ground and cartridge fuses in circuits of any voltage where accessible to other than qualified persons so that each individual circuit containing fuses can be independently disconnected from the source of power. However, a current-limiting device without a disconnecting means is permitted on the supply side of the service disconnecting means. In addition, a single disconnecting means is permitted on the supply side of more than one set of fuses as permitted by the exception in § 1910.305(j)(4)(vi) for group operation of motors, and a single disconnecting means is permitted for fixed electric space-heating equipment.
(iv) Overcurrent devices shall be readily accessible to each employee or authorized building management personnel. These overcurrent devices may not be located where they will be exposed to physical damage or in the vicinity of easily ignitable material. Open (f)(1)(iv) 101 citations
(v) Fuses and circuit breakers shall be so located or shielded that employees will not be burned or otherwise injured by their operation. Handles or levers of circuit breakers, and similar parts that may move suddenly in such a way that persons in the vicinity are likely to be injured by being struck by them, shall be guarded or isolated. 1 citations
(vi) Circuit breakers shall clearly indicate whether they are in the open (off) or closed (on) position. 1 citations
(vii) Where circuit breaker handles on switchboards are operated vertically rather than horizontally or rotationally, the up position of the handle shall be the closed (on) position.
(viii) Circuit breakers used as switches in 120-volt and 277-volt, fluorescent lighting circuits shall be listed and marked “SWD.” Open (f)(1)(viii) 31 citations
(ix) A circuit breaker with a straight voltage rating, such as 240 V or 480 V, may only be installed in a circuit in which the nominal voltage between any two conductors does not exceed the circuit breaker's voltage rating. A two-pole circuit breaker may not be used for protecting a 3-phase, corner-grounded delta circuit unless the circuit breaker is marked 1Φ—3Φ to indicate such suitability. A circuit breaker with a slash rating, such as 120/240 V or 480Y/277 V, may only be installed in a circuit where the nominal voltage of any conductor to ground does not exceed the lower of the two values of the circuit breaker's voltage rating and the nominal voltage between any two conductors does not exceed the higher value of the circuit breaker's voltage rating.
Source: eCFR, text current as of 2026-10-15. Read all of 1910.304.
Where and how often it was cited
| Year | Citations |
|---|---|
| 2023 | 9 |
| 2024 | 54 |
| 2025 | 49 |
| 2026 | 24 |
Top states: NY (25), VA (23), HI (18), TX (16), PR (12)
Largest penalties
| Employer | Location | Penalty for this rule |
|---|---|---|
| FAMILY DOLLAR STORES OF VIRGINIA INC. | COVINGTON, VA | $25,519 |
| THE GOODYEAR TIRE & RUBBER COMPANY | DANVILLE, VA | $10,220 |
| PYRAMID SPA PRODUCTS, LLC. | BROOKSHIRE, TX | $10,141 |
| CHART INC. | BEASLEY, TX | $7,835 |
| RACK BUILDERS, INC. | QUINCY, IL | $7,661 |
Free toolbox talk
A 5-minute crew talk on 1910.304(f)(1), plus alerts when this rule changes. Free.
OSHA interpretation letters
None exist. OSHA has not published a letter of interpretation for 1910.304(f)(1).
Related parts of this rule
- 1910.304(f) Overcurrent protection 136 citations
- 1910.304(f)(1)(iv) 101 citations
- 1910.304(f)(1)(viii) 31 citations
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Frequently asked questions
Which circuits does 1910.304(f)(1) cover?
Circuits rated 600 volts, nominal, or less.
When is a disconnect required on the supply side of fuses?
For all fuses in circuits over 150 volts to ground, and cartridge fuses in circuits of any voltage where accessible to other than qualified persons, with listed exceptions.
Can an overcurrent device open only the grounded conductor?
No. Except for motor running overload protection, it may not interrupt the grounded conductor unless all conductors are opened at the same time.
About this page
Sources
- 29 CFR 1910.304 (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 2026-10-21
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.