Selective 4-pole RCD for 5SY series
The Siemens SENTRON 5SM2842-8 is a selective residual current unit (RC unit) designed for use with the 5SY miniature circuit breaker series. It is a 4-pole device rated at 40 A AC with a tripping fault current of 1000 mA, type A, making it suitable for detecting sinusoidal AC and pulsating DC residual currents in TN and TT systems.
What selective means for coordination
The selective design (short-time delayed) allows this RCD to coordinate with downstream devices. Under a fault, the downstream RCD trips first, keeping the 5SM2842-8 closed and maintaining supply to the rest of the installation. This avoids a full-panel blackout when a single branch faults — critical for process continuity in industrial panels. The 5 kA surge current resistance confirms it can handle transient overvoltages without nuisance tripping.
DIN-rail fit and panel integration
Mounts on DIN rail (REG), occupying 4 modular width units. Installation depth is 70 mm, total depth 77 mm. IP20 applies when installed in a distribution board with conductors connected.