An electrical junction box is configured to be attached to a vehicle. The box includes a container that has a front opening and a cavity located behind the front opening. A cover is movably attached to the container, so it can be moved into a closed position covering the front opening. A socket, to which an electrical supply cable can be removably connected, is fixed to the container beside the front opening. Breakers are secured to the container within the cavity. Each breaker has an input terminal and an output terminal. Each input terminal is electrically connected to the supply cable via the socket. Electrical distribution lines connect the breakers' output terminals to components of the vehicle that are outside the cavity.