Abstract: A voltage supply apparatus for providing a supply voltage for electric devices in an aeroplane cabin comprises a socket (22) to which the electric device is connectable by means of a plug (38). The socket (22) comprises plug detectors (45, 46) detecting the presence of the plug in the socket (22). A supply device (16) is arranged remotely from the socket (22) and is connected to the socket (22) via a signal line (18) and via a supply line (20) for the supply voltage. The supply device (16) applies the supply voltage to the socket (22) if the plug detectors (45, 46) indicate the presence of the plug (38) via the signal line (18) to the supply device. The supply lines (20) and the socket (22) are only alive if the insertion of a plug (38) has been detected. In this way, a danger to people due to manipulations on the socket or on the supply line is excluded.