OSHA 29 CFR 1910.147 requires employers to:

• Develop a written energy control program and documented procedures for each piece of equipment or type of equipment
• Train authorized employees (who perform the lockout) and affected employees (who work in the area) on energy control procedures
• Provide energy-isolating devices — padlocks, hasps, breaker lockouts, valve lockouts — capable of accepting only one key, held exclusively by the authorized employee
• Conduct annual inspections of energy control procedures
• Use tagout devices only where lockout devices cannot be applied; tagout alone provides less protection than lockout

The standard applies to all energy sources including electrical, hydraulic, pneumatic, mechanical, chemical, and gravity/stored energy. It does not apply to work on cords and plugs (use NFPA 70E and plug lockouts) or hot work under NFPA 70E for energized electrical work.

A lockout uses a physical locking device (padlock) to hold an energy-isolating device — circuit breaker, valve, disconnect switch — in the safe (de-energized) position. The padlock has a unique key held exclusively by the authorized employee. No one else can re-energize the equipment while the lock is in place.

A tagout uses a warning tag attached to the energy-isolating device to warn others not to operate it. Tags are not a physical restraint — they cannot prevent accidental or unauthorized re-energization. OSHA requires that lockout be used wherever the energy-isolating device is capable of being locked; tagout-only programs are permitted only when the equipment design physically prevents the use of a lockout device.

A group lockbox (also called a group lock box or shadow box) is used when multiple authorized employees need to work simultaneously on the same piece of equipment under lockout. The procedure works as follows:

• One authorized employee applies locks to all energy isolation points on the equipment, then places all the keys inside the group lockbox
• Each worker applies their own personal padlock to the hasp of the lockbox
• The equipment remains locked out until every worker removes their personal padlock from the lockbox — no single person can access the equipment keys until all workers are clear

Group lockboxes are required wherever more than one authorized employee is working on the same equipment simultaneously under the same energy control procedure. The Master Lock 498A portable group lockbox and 503 Latch Tight lockbox are in this category.

Breaker lockout selection depends on the breaker toggle size and panel voltage:

• Standard 120V–240V residential/light commercial breakers (standard height, tie-bar toggles): use the Master Lock Grip-Tight Standard or Brady Clamp-On 120/277V
• High-voltage/high-amperage breakers (wide or tall toggles): use the Master Lock Grip-Tight Wide & Tall or Brady Clamp-On 480/660V
• Oversized industrial breakers (up to 2-1/4" wide × 7/8" thick): use the Brady Oversized Clamp-On 480/660V

When in doubt, measure the breaker toggle width and thickness before ordering. Breaker lockout devices that don't fit the toggle securely provide inadequate protection. Call Safe-Fast at 1-800-723-3620 for selection help.