29 CFR 1910.333: OSHA Electrical Work Practices

Regulatory citation: 29 CFR 1910 Subpart S, Electrical Safety-Related Work Practices (1910.331–335)

What Are OSHA's Electrical Safety-Related Work Practices?

29 CFR 1910.331 to 1910.335 set work practices to protect general industry employees from electric shock and burns when working on or near electrical equipment. They cover when equipment must be de-energized, how to lock it out, who is qualified to work on live parts, and the protective equipment required.

Why Electrical Work Practices Matter

Electrical hazards cause electrocutions, arc flash burns and falls from shocks. Many incidents involve workers who assumed equipment was de-energized or weren't trained to recognize electrical hazards.

Core Requirements

1. De-Energize First

Live parts that an employee may be exposed to must be de-energized before work begins, unless de-energizing would create greater hazards or is infeasible due to equipment design or operational limitations. Live parts operating at less than 50 volts generally don't need to be de-energized if there's no increased exposure to burns or explosions.

2. Lockout and Tagout

When equipment is de-energized, it must be locked and tagged out using written procedures, and a qualified person must verify that equipment is de-energized before work begins.

3. Qualified and Unqualified Persons

Only qualified persons, trained in the construction and operation of the equipment and its hazards, may work on or near exposed energized parts. Unqualified persons must stay a safe distance away.

4. Approach Distances and Overhead Lines

Employees must keep minimum approach distances from exposed energized parts and overhead power lines, based on voltage and qualification.

5. Protective Equipment and Tools

Employees working near electrical hazards must use electrical protective equipment and insulated tools appropriate for the exposure.

Common Compliance Approaches

Adopt an Electrical Safety Program

Many employers use NFPA 70E, a widely recognized consensus standard, to build their electrical safety program, including arc flash risk assessments.

Define Qualified Persons

Document who is qualified for which voltages and tasks, and train them accordingly.

Test Before Touch

Make verifying absence of voltage a mandatory step before any electrical work.

Example: Electrical Safe Work Practices in Practice

A manufacturing plant needs to replace a motor starter in a 480-volt panel. A qualified electrician follows the written lockout procedure, opens and locks the disconnect, and uses a properly rated voltage tester to verify absence of voltage before starting. Other maintenance staff, who aren't qualified for energized work, are kept outside the approach boundary while the panel is open.

Related regulations: OSHA Lockout/Tagout, OSHA PPE Standards, UK PUWER 1998.

Note: This summary reflects federal OSHA requirements. States with OSHA-approved State Plans may have additional or different requirements. Always check the current regulation text and any state rules that apply to you.

Frequently Asked Questions

When can OSHA allow work on energized equipment?

Energized work is permitted only when de-energizing would create greater hazards, such as shutting down life support or ventilation, or when it's infeasible due to equipment design or operational limitations, such as some diagnostic testing. It must then be done by qualified persons using appropriate safe work practices and PPE.

What is a qualified person under OSHA's electrical rules?

A qualified person has training in avoiding electrical hazards when working on or near exposed energized parts, including how to distinguish exposed live parts, determine voltage and maintain safe approach distances.

Is NFPA 70E required by OSHA?

NFPA 70E is a consensus standard, not an OSHA regulation. However, OSHA often references it as a way to meet electrical safety requirements, and many employers use it to guide arc flash and shock protection programs.