A corrosion resistant electrical system for communicating between a power source and multiple electric devices on a truck box or trailer. A hard plastic junction block with a male connector for power input communicates internally with two or more female connectors for power output, allowing multiple electric motors or other devices to receive electricity from a single power cable. The assembly includes cables with female or male connectors at the ends, the connectors having corresponding projecting portions and passageways, and U-shaped flanges and spaces, that fit together. The space between the projecting portions and the passageways are sealed by a resilient gasket around the projecting portion, and the U-shaped flanges and projecting portions contain aligned apertures to receive a lock pin to secure the mated connectors together.