The Siemens SENTRON 5SM3646-5KK14 is a 4-pole selective residual current circuit breaker (RCCB) rated for 63 A at 40 °C with a 300 mA residual trip threshold. The Type B+ characteristic means it detects AC, pulsating DC, smooth DC, and high-frequency residual currents — covering VFD-fed loads, UPS systems, and EV charging circuits where standard Type A or AC devices would be blind to DC fault components. The selective (time-delayed) design coordinates with downstream 30 mA RCCBs so that only the faulted branch trips, keeping the rest of the distribution board live. Rated short-circuit current withstand is 10 kA, with an additional rating of 0.8 kA per EN 60898 and IEC 61008-1.
Integration notes
Panel integration is straightforward: the 77 mm depth and 72 mm width fit standard DIN-rail enclosures with 4 module spaces. Installation depth of 70 mm leaves clearance for wiring behind the rail. The device is silicon-free — relevant for potting or conformal-coating processes in vibration-prone or humid environments. The temperature derating curve is published: full 63 A up to 45 °C, then 60.5 A at 50 °C, 58 A at 55 °C, 55.4 A at 60 °C, 52.9 A at 65 °C, and 50.4 A at 70 °C. The permissible I²t value of 70,000 A²·s and let-through current of 7,500 kA are coordination values for the upstream MCB or fuse — keep those figures handy for the selective coordination study.