The system provides for controlling the connection of electrical power sources to electrical loads installed on a motor vehicle and limiting exposure of personnel to relatively high electrical voltages from the electrical power sources. The system includes a serial communication bus and power cables routed through the motor vehicle. At least a first connector is provided through which the serial communication bus and a power cable are routed allowing temporary severing of the serial communication bus and the power cable. The power cable includes a circuit interrupter which isolates the connector from the electrical power source in response to certain conditions on the serial communication bus, including, but not limited to, the cessation of data traffic on the serial communication bus.