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.

An electrical isolation system for a high voltage battery circuit in an electrified vehicle, the electrical isolation system mounted to a chassis of the electrified vehicle and comprising: an overcurrent protection switch that is configured to be responsive to leakage current present in the high voltage battery circuit by breaking the high voltage battery circuit and a redundant overcurrent protection circuit that is configured to be responsive to leakage current present in the high voltage battery circuit in a manner that is different from the overcurrent protection switch to break the high voltage battery circuit such that the redundant overcurrent protection circuit is more responsive in one or more fault modes of the electrified vehicle than is the overcurrent protection switch alone, wherein the system is included in a control unit of the electric vehicle