A control apparatus (1) for controlling an electrical load (2) has a housing (28), a plug (12) mounted to the housing (28) for connecting the control apparatus (1) to the power outlet (4), a socket (10) mounted to the housing (28) for connecting the control apparatus (1) to the electrical load (2), and a receiver unit (6) mounted within the housing (28) and coupled to the plug (12) and the socket (10). In use, the receiver unit (6) receives a control signal that is indicative of an impending congestion period. Upon receipt of the control signal, the receiver unit (6) interrupts supply of power to the socket (10) and, hence, switches the electrical load (2) off.