Earth leakage relays (also known as ELRs or by the alternative name of differential relays) are specialised latching relays used to monitor the leakage of current to earth on 3-phase electrical systems, interrupting the circuit if a dangerous voltage leak is detected. Earth leakage relays can be found in domestic distribution boards and are used to sense insulation failures, preventing electric shocks.
Earth leakage relays monitor a circuit for significant leakage between the electrical supply and the earth by tracking the current that flows through both the phase conductor and neutral conductor of the electrical circuit. If the phase and neutral currents are equal and balanced, the relay will not interrupt the circuit as there is no difference between the two, and therefore, there will be no signs of voltage leakage. However, if there is a difference, the relay will interrupt the flow of the current and trip the breaker, switching the circuit off to prevent any injury via electric shock.
Earth leakage relays come equipped with a range of features designed for effective earth leakage monitoring and protection. These features often include:
In Australia, earth leakage protection is primarily governed by AS/NZS 3000 (Wiring Rules), which mandates Residual Current Devices (RCDs), including earth fault relays, to ensure electrical safety. For residential and most commercial circuits, a highly sensitive tripping current not exceeding 30mA is required to protect people from electric shock. Industrial environments have varying requirements based on specific risks, making earth leakage monitoring relays with adjustable settings crucial for preventing equipment damage and fire from earth faults.
IP ratings are particularly important for Australian industrial and outdoor applications. Indoor industrial settings often require a minimum of IP20, providing protection against solid objects. Outdoor applications typically need IP54 or higher to protect against dust and water ingress, ensuring reliable operation in challenging conditions.
Compliance with both Australian (AS/NZS) and international IEC standards is essential for all earth leakage relays used in Australia. Certification from recognised Australian authorities confirms that the earth leakage protection relay has undergone rigorous testing to meet these standards, ensuring its reliability and effectiveness in preventing electrical hazards.
Earth leakage protection relays are essential components in various industries to ensure electrical safety and prevent equipment damage. Here are some examples of their applications:
RS is your trusted supplier and distributor for earth leakage relays in Australia. We offer a comprehensive range of high-quality earth relays from renowned brands like Broyce Control, Lovato, and Schneider Electric. You can find an earth leakage relay price to suit your budget, whether you need ELR relays for industrial machinery or general electrical safety, RS provides quality products and reliable service to meet your needs, alongside a wide selection of circuit breakers for complete circuit protection. For more details on delivery services and fees, please refer to our Delivery Page.