An onboard electrical junction box. The onboard electrical junction box comprises an auto-change-over switch adapted to acquire: a first state wherein power is supplied to the electrical system from a power rail via at least one onboard power collector device; and a second state wherein power is supplied to the electrical system from a removable shore power source, wherein during operation in the second state, the at least one onboard power collector device is isolated from the power supplied by the removable shore power source. The onboard electrical junction box also comprises a switch control module in electrical communication with the auto-change-over switch for causing the auto-change-over switch to acquire the second state upon detection that: the removable shore power source has established an electrical connection with the onboard electrical junction box; and the electrical system of the vehicle is receiving power below a predetermined threshold.