Most mains operated equipment in use today is connected to the supply via plugs and sockets. These are generally acceptable in benign environments but can be unsafe or have limited life in the presence of moisture. In explosive atmospheres and in undersea applications special connectors must be used. This paper describes a technique, the Contactless Energy Transfer System (CETS), by which electrical energy maybe transmitted, without electrical connections or physical contact, through non-magnetic media of low conductivity. CETS, which has been used to transfer upto 5KWs across a 10mm gap, employs high frequency magnetic coupling and enables plug in power connections to be made in wet or hazardous environmental conditions without the risk of electric shock, short-circuiting or sparking. Energy may be transmitted without the necessity for accurately manufactured ?plug and socket? mechanisms and may be transmitted from source to load even when there is a relative motion. Load source voltage matching may be made inherent to the system..