The A51E is an addressable relay providing double pole, volt free, change-over contacts, rated to switch local mains supplies. The unit is intended for installation within the equipment to be switched, thereby offering savings in installation costs when compared to long, auxiliary circuit, wiring runs out from the control panel. Certified to EN54-18, the relay can be located anywhere on the two core ZP loop and is designed for power up or shut down of the mains electrical supply to ancillary equipment. The unit is ideal for the control of associated system equipment such as mains fed magnetic door release circuits, extract fans and dampers.