The embodiments of a “SAVUS” disclosed herein are simple, safe, low cost devices used to connect emergency power to an entire home. The embodiments of SAVUS are configured to install into most residential types of circuit breaker front panels and require only one available circuit breaker space for installation. SAVUS mechanically interlocks with the main circuit breaker and will not allow connection of an external power source to the circuit breaker box until utility power is turned off for safety.