ELM Earth Leakage Protection Relay

The Ampcontrol ELM relay is electronic in design and is based on microprocessor technology. It is housed in a stainless steel enclosure and can be either DIN rail mounted or panel mounted which provides IP56 ingress protection.

The relay uses a toroid to measure earth fault current. A definite time operating characteristic is provided with adjustable trip sensitivity and time delay. When a fault occurs and the trip level and time delay is exceeded, the relay’s trip function is activated, operating the trip contacts connected in the system control circuit. The trip is latched in non-volatile memory and requires operation of the reset input to clear the trip condition. A ten segment bar graph indicates the percentage of leakage level being detected.


The relay is suitable for general industry where equipment or system earth leakage protection is required. The ELM is designed for use on earth fault-limited systems and continually monitors the toroid output. Should the connection be lost the relay will trip and flash the “CT Fault” LED.