RCCB for harsh environments
The Siemens 5SV3747-5 is a 4-pole residual current operated circuit breaker (RCCB), type B selective, rated at 80 A with a 500 mA trip sensitivity on a 400 V AC system. The type B selective characteristic means it handles smooth DC residual currents and high-frequency AC waveforms — common on variable-speed drives, UPS systems, and PV inverters — without nuisance tripping, while the selective (S-type) design introduces a deliberate time delay for coordination with downstream RCCBs. The SIGRES designation confirms it's built for harsh ambient conditions with an extended test interval, so it's suited for industrial environments where moisture, dust, or aggressive atmospheres are present.
Packaged singly, dimensions 78 x 97 x 85 mm. Mounts on standard DIN rail in the distribution board. The 4-pole form factor occupies four modular-width spaces. For a critical spare on a legacy install running drives or UPS-backed circuits, keep one in the cabinet — the type B selective response covers the DC fault currents that standard AC-type RCCBs miss.