RD series

Residual current relays for leakage current protection

The RD series of residual current relays is designed for leakage current detection, protection and monitoring functions, when used in conjunction with an external toroidal transformer belonging to the TR family. It is composed by DIN-rail mounted RD2 and RD3 relays.

The RD2 relays are designed for leakage current detection and are classified as “A Type” according to IEC/EN62020. They are sensitive to leakage sinusoidal currents and to leakage pulsating currents with direct components.

The RD3 family of electronic residual current relays provides residual current protection and monitoring functions according to IEC/EN 60947-2:2006 annex M.

Main benefits

Complete range

Complete range of electronic residual current devices, in accordance with the international Standard IEC6094 -2, Annex M

High safety & protection levels

The right solution for residual current protection for all levels of low-voltage installations, from low-voltage lines to power distribution, up to terminal distribution

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Flexibility

RD2 and RD3 residual current devices are combined with a wide range of toroids with diameters from 29 mm to 230 mm (for cables and busbars), which provides the maximum application flexibility for an effective protection in every point of the system

Product details

Reduction of unwanted tripping

Protection and control in every point of the system

Flexibility of installation and use

RD2 and RD3 residual current devices perform leakage current measurement through a frequency filtering that allows an increased immunity against high-frequency currents, not hazardous to man, that are typically generated by inverters and the main cause of unwanted tripping of residual current devices.

Moreover, some of the range's models feature a pre-alarm threshold adjustment that signals, through an output contact, when a given residual leakage current is reached.

By removing most of the unwanted tripping of residual current devices, a high degree of safety on the systems can be reached, along with a high level of service continuity.

Thanks to the wide current adjustment range (from 30mA to 30A) and to the large number of toroids available (openable and closed for cables or busbars), RD2 and RD3 residual current devices ensure effective protection in every point of the system.

Furthermore, both devices perform the RMS measure of earth leakage current. This means that the devices measure any type of signal, calculating the actual RMS value, averaged according to the frequency filtering.

The RD series allows easy installation as it is available in a compact miniature design. Combined with the extensive time setting capabilities and myriad tripping functions of ABB low voltage circuit breakers, various levels of selectivity can be achieved to ensure complete selectivity in the event of an insulation fault in the system.

Moreover, the supply of residual current devices from an auxiliary network provides the user with great flexibility.