Powerplant Light Safe 4 Socket 13 Amp Relay unit plug into your existing timer to protect against the inductive loads generated by the electrical discharge of horticultural lighting. The Light Safe 13 Amp Contactor Relay unit range can switch a maximum of 13 Amp of discharge lighting. In practice this is the equivalent to 1 x 1000, 3 x 600watts, or 4 x 400watts. However this can vary according to the make and condition of the lighting system used.