The Siemens SENTRON 5SV4314-0KL is a 2-pole residual current circuit breaker (RCCB) with a Type AC characteristic, rated for 40 A at 230 V AC and a 30 mA trip threshold. It's built to IEC 61008-1 standards, with a 10 kA short-circuit current rating and a permissible I²t of 58,000 A²·s. This is the instantaneous version — no intentional delay — so it trips fast on a ground fault.
Push it to 45 °C and you're down to 38.1 A; at 55 °C it's 32.29 A; at 65 °C it's 23.3 A. The 30 mA trip is standard for personnel protection (shock hazard) per most wiring codes. The let-through current is capped at 5,200 A, and the I²t is 58,000 A²·s — both figures matter for coordination with the upstream MCB or fuse.
Snaps onto DIN rail (REG) and takes 2 modular width units at 60 mm grid spacing. The 36 mm width and 70 mm depth fit standard 4-module enclosures. Mount in any position, feed from top or bottom. IP20 with conductors connected — fine inside a distribution board, not for wet locations. Silicon-free construction, which matters if you're potting or coating the panel.