You can lock a circuit breaker by using the right circuit breaker lock. Circuit breaker locks are typically easy to use and easy to secure. Clamp-on locks in particular can easily be clamped over a circuit breaker switch, then secured with a lockout tagout safety padlock.
It’s also important to make sure that these circuit breaker locks are correctly tagged. This way, other employees can be informed of why the circuit breaker is locked out, who installed the lock, when it was installed, and more.