The Siemens 5SM3644-4BG is a 4-pole residual current circuit breaker (RCCB) with Type B tripping characteristic, rated 40 A continuous current and 300 mA residual fault sensitivity at 400 V AC. Type B means it detects AC pulsating DC and smooth DC fault currents — the full spectrum you get from variable-speed drives, UPS systems, and rectifier-fed loads. The short-time delayed (S-type) selectivity rating means it coordinates with downstream RCCBs so only the faulted branch opens, not the whole sub-distribution board.
Siemens 5SM3644-4BG 4P Type B RCCB, 40A 300mA 400V
MPN5SM3644-4BG
Siemens 5SM3644-4BG, 4-pole Type B residual current circuit breaker, 40 A rated current, 300 mA sensitivity, 400 V AC, short-time delayed.
Sourced new & surplus through independent channelsAuthenticity-screened · ESD-safe packingListing updated Jul 2026
Product details
Frequently asked questions
Where can I buy 5SM3644-4BG and how do I get a price?
This part is sourced to order against an RFQ through independent distribution. Submit a request for quote; availability and current pricing are confirmed at quote time.
What does Type B mean on this RCCB?
Type B detects AC pulsating DC and smooth DC residual currents. That covers the fault spectrum from modern electronics — drives, UPS systems, rectifiers — where a standard Type A would miss a pure DC fault.
What is the rated sensitivity and voltage of 5SM3644-4BG?
Rated residual current is 300 mA, rated voltage is 400 V AC. The short-time delayed characteristic (S-type) provides selectivity grading in multi-level distribution.
MPN
5SM3644-4BG