What this RCCB is and what it protects
The Siemens 5SV5644-6 is a 4-pole residual current operated circuit breaker (RCCB) from the SENTRON family, rated 40 A at 230/400 V AC, 50 Hz, with a 300 mA tripping fault current and Type A residual current sensitivity. It is designed for residential and light commercial distribution boards where earth-leakage protection is required on a 4-wire (3-phase + neutral) supply. Type A detection means it responds to sinusoidal AC residual currents and also to pulsating DC residual currents up to 300 mA — the common waveform from rectified loads like switching power supplies, LED drivers, and variable-speed drives. The 6 kA short-circuit current rating (SCCR) per IEC 61008-1 ensures the device withstands fault currents up to that level without rupturing, provided the upstream protective device is coordinated.
Mounting and panel integration
Snaps onto a DIN rail (REG profile) and occupies 4 modular width units (72 mm). Depth is 70 mm, height 90 mm. Mounting position is unrestricted — any orientation is permitted. The supply can enter from top or bottom, which simplifies busbar routing in crowded enclosures. IP20 rating applies only when the distribution board is installed and conductors are connected — the device itself is not sealed against dust ingress in an open panel. Operating ambient range is -5 °C to 45 °C; storage range extends from -40 °C to 75 °C.