Abstract: A run time recorder device (1,10) monitors the operating time of an electrical appliance driven by AC. The device is coupled to the supply voltage and monitors the supply by determining the operating time of the appliance from the number of repetitions of the periodic wave form of the supply voltage. A reading device for use with the recorder device may be coupled to the recorder device either by the supply leads or via a contactless coupling for the transmission and reception of signals to and from the recorder device. A regulating device (200) for regulating a load apparatus (144) comprises a controller (110), a memory (116) for storing an instruction data set means (118) for monitoring a condition such as temperature which is used by the controller to determine when to change the operating state and an interface (120) for communicating with the load apparatus.