The Siemens 5SV3748-6 is a 4-pole residual current operated circuit breaker (RCCB) from the RCCB family, rated at 100 A with a 500 mA sensitivity, for 400 V AC systems. Type A detection means it catches sinusoidal AC faults plus pulsating DC faults — the kind you get from rectified loads like VFDs or switched-mode power supplies. That 500 mA trip threshold is on the higher end, sized for equipment protection rather than personnel shock protection (which typically needs 30 mA or lower). It's built for DIN-rail mounting inside a panel, four poles wide. The 100 A continuous rating matches feeder circuits feeding sub-panels or heavy motor loads, and the 400 V AC rating covers 3-phase line-to-line voltages common in industrial distribution.
This is a stocked catalog item from Siemens. If you're filling a BOM line that calls for a 100 A Type A RCCB at 400 V, the 5SV3748-6 fits that spot.