A system (5) for controlling the activation of an electrical load comprises a receiving device for receiving an ambient condition input, an output device - in communication with said receiving device and arranged to output a signal proportional to the ambient condition input - and a controller (20) for receiving the signal from said output device and comparing said signal to a reference value. Said controller (20) is arranged to deactivate a switch (40) in communication with said electrical load on detecting the signal exceeding the reference value and activating the switch (40) when the signal falls below said reference value.
