Fastening the screw pushes out a hole for a Lockout/Tagout padlock shackle. Locking the padlock will lock the circuit breaker's switch in place to enable safer interventions.

The S2329 Master Lock aircraft circuit breaker lockout prevents accidentally re–energizing an electrical system by locking a circuit breaker in the “off” position.

Types WL-2 and WL lockout relays (LOR) automatically trip and lock out circuit breakers and other devices to protect against damaging electrical faults.

If the circuit breaker trips, the power will be cut off, regardless of whether or not the handle is allowed to move. To demonstrate, I installed a circuit breaker lockout at my own panel and made ...