The present disclosure relates to an electrical protection system, including a breaker enclosure and associated terminals, and the methods of use therefor that allow for a circuit breaker or other electrical protection device to be safely added or removed from a circuit while power is supplied to at least one of the terminals. The disclosed enclosure and terminals include a series of interrelated safety features that prevent a user from accidentally completing the circuit from one terminal to another when the electrical protection system would be in an unsafe state. The combination of features described herein allow for a replaceable electrical protection device for equipment under load to be realized, thus improving user safety.