The Siemens 5SV3746-4 is a SENTRON residual current circuit breaker (RCCB) — a 4-pole, Type B device rated for 63 A continuous at 40 °C through 55 °C, with a 500 mA residual trip threshold. Type B means it detects AC, pulsating DC, smooth DC, and high-frequency residual currents, so it covers VFD-fed motor circuits, UPS feeds, and EV charging infrastructure where pure AC-sensing RCCBs would miss DC fault components. The short-time delayed design (SIGRES function) lets it ride through transient earth faults without nuisance tripping, which matters on circuits with surge arrestors or capacitive filters that dump a brief ground current on power-up.
The supply can enter top or bottom; the SIGRES function stays powered even when switched off if fed from the top. IP20 with conductors connected, so it lives inside a distribution board, not exposed to washdown.
Thermal derating and fault handling
At 65 °C it derates to 55 A; at 70 °C it drops to 48 A. Short-circuit withstand is 10 kA per IEC 61008-1, with a let-through current limit of 7 000 A and an I²t of 60 000 A²·s. Surge current resistance is 3 kA; the impulse withstand per the standard is 0.8 kA. Overvoltage category III — suitable for fixed-installation distribution panels.