The socket series RE… and plug series PL… are made of aluminium. The socket is for fixed installation and manufactured in 3 sizes for rated current of 16A, 32A and 63A. The RE… series of socket outlets are provided by interlock mechanism, in such a way that the plug can be inserted when internal switch is off and cannot be removed when the internal switch is on. The RE… series of socket outlet are composed of a body incorporating two threaded cable/conduit entries, a threaded cover and a coupling which contains the insulated socket with corresponding pins for various configuration. The PL… series of plugs is composed of a cylindrical body having one threaded cable entry for cable connection by means of a cable gland, and an engagement ring with gasket is located on the plug for guarantee the mechanical coupling with the socked once inserted. When the plug inserted the first pin making connection to the socket is the earth pin, when the plug is withdrawn the last pin making contact is the earth pin, this assembly arrangement ensures an always ground connection.