Circuit Breaker Lockout prevents unauthorized access to a specific circuit breaker When you’re doing electrical work and you’ve turned a circuit breaker off, you can’t allow someone to come along and inadvertently turn it back on. Our circuit breaker lockout assures that the locked breaker stays off. Or maybe there’s a breaker that you want to make sure stays on. Either way, our circuit breaker lockout locks the switch in the position you want —on or off— and is designed to fit 120V breakers with holes in the switch tongue. Circuit breaker lockout’s dual cavities accommodate different size switch tongues. Use a padlock (not included) with a shackle up to 9/32" in diameter. 0.83"H x 0.35"W x 2.15"L.