Type EFU-1 is part of the Optima range of low cost, high specification earth fault relays and is designed for a variety of single phase applications where space, economy and ease of installation are important considerations.

The EFU-1 is compact, robust, and fully encapsulated, providing high immunity against shock vibration and harsh environments and is available with a choice of factory set earth leakage trip levels from 10 mA to 300 mA. The fast disconnection time and rugged construction make it eminently suitable for direct installation on plant or machinery to provide the optimum protection at all times.

Built into the EFU-1, are a core balance C.T. and a heavy duty, 2-pole relay with 3-mm contact clearance for line and neutral switching. Considerable savings of time and money result from the fact that there is no need for an external C.T. or contactor! An integral test and reset button are fitted as standard and colour coded fly leads are provided to facilitate connection.