Circuit Breaker Lockouts

A manually operated circuit breaker can serve as an energy-isolating device under OSHA 29 CFR 1910.147. A push button, selector switch, or control circuit alone cannot provide that isolation. A breaker lockout helps prevent someone from switching an isolated circuit back on, but the device must fit the breaker and be used as part of the employer's energy-control procedure.

Choose a compatible breaker lockout

Breaker designs vary. Pin-style devices fit certain breakers with compatible openings; clamp-on and no-hole styles fit specified switch handles; and some multipole breakers use a lockout designed for their linked handles. Check the breaker and lockout manufacturer's instructions for compatibility, installation, and padlock requirements. A device that does not grip securely or prevent operation is not a suitable choice.

Isolation and verification come first

Identify all energy sources that can affect the equipment, use the designated disconnecting means, control stored energy, and apply the lockout device and personal lock in the sequence required by the written procedure. Do not assume that an OFF handle or attached padlock proves the circuit is deenergized. When employees will work on or near exposed deenergized electrical parts, OSHA 29 CFR 1910.333 requires a qualified person to verify the deenergized condition with appropriate test equipment.

When is a tag required?

The answer depends on the work. OSHA 1910.147 governs hazardous-energy control during machine servicing and maintenance; it does not require a separate tag with every lock. For work exposing employees to parts of fixed electrical equipment or circuits, OSHA 1910.333 generally requires a lock and a tag on each disconnecting means, with specific exceptions and conditions in the standard. When used, the tag must prohibit unauthorized operation and removal; no single retail tag phrase is mandatory for every situation.

Use the equipment-specific procedure and applicable OSHA standard to select the breaker lockout, lock, and tag. The lockout device supports the procedure; it does not replace isolation, testing, or the protections required for every employee involved.