Earth leakage protection relay mounts on Din rail

Paul Boughton
FDB Electrical is introducing the EFR-4/EFR-5 earth leakage protection relay that forms part of the company's extensive Optima range of low-cost, high-specification residual current devices and can be specified at a wide range of trip levels and response times for precise system protection. The EFR-4/EFR-5 is designed for medium- to high-current applications where space is a limitation. It is housed in a compact Din-rail mounting enclosure complete with integral 28mm or 46mm sensory coil and fitted with test and reset buttons, and LED status indication.
This non-invasive sensing of 28mm (EFR-4) or 46mm (EFR-5) cable capacity is a significant factor in speedy installation for larger industrial and automated machines, such as electric motors and automated manufacturing assembly lines.
Fully encapsulated construction of the EFR-4 and 5 provides excellent temperature stability, together with high immunity against shock and vibration. Housed in flame-retardant ABS material as standard, the EFR-4/EFR-5 has built-in features that include fail-safe operation, manual reset after a fault trip, auto-reset after a power failure, and trip status latched until reset (with power supply on). A non-failsafe version is available to special order for use in applications where shunt tripping of primary/supply breakers makes failsafe operation impractical.
The EFR-4/EFR-5 is designed to react to alternating currents only and to reject stray DC signals. It maintains accuracy over a wide frequency band from 5Hz to 800Hz, making the unit suitable for use on variable-frequency drives. The EFR-4/EFR-5 can be used on solid, medium- or high-resistance grounded installations and, by using the recommended artificial ground package, even on ungrounded installations.
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