The Siemens 5SU1356-1DV40 is a combined residual current device and miniature circuit breaker (RCBO) — an FI/LS-protector — in a single 1+N-pole module. It pairs a Type AC residual-current element (30 mA trip threshold) with a C-curve overcurrent characteristic rated at 40 A, all in a 70 mm deep housing with a pigtail connection for the neutral. The 30 mA sensitivity covers personnel protection against direct contact (the standard for socket-outlet circuits in most residential and commercial installations per IEC 60364).
Integration notes
The 70 mm depth (D=70MM) is a standard dimension for DIN-rail mounted RCBOs, so it fits alongside other modular devices in a consumer unit or sub-distribution board without protruding past the enclosure cover. The pigtail neutral connection means the installer routes the factory-attached neutral lead to the neutral busbar — no separate neutral link to wire inside the module itself.