The Siemens 5SM3648-2 is a SENTRON selective residual current operated circuit breaker (RCCB), 4-pole, type AC, rated at 100 A with a 300 mA tripping fault current for 400 V AC 50 Hz systems. Its selective design (short-time delayed) means it coordinates with downstream RCCBs — during a ground fault, this unit stays in until the downstream device clears, keeping upstream circuits live. Rated short-circuit current withstand is 10 kA per EN 60898 and IEC 61008-1, so it handles fault currents up to that level without self-destructing.
Mounting and panel fit
Snaps onto DIN rail (REG profile), occupies 4 modular width units (about 72 mm), installation depth 70 mm. Supply can enter from top or bottom. IP20 with the distribution board installed and conductors connected — standard for enclosed panel use, not for wet environments. Mount in any position; no derating for orientation.
Thermal limits and power loss
Ambient operating range -5 °C to 45 °C; storage range -40 °C to 75 °C. Per-pole power dissipation at rated current in hot operating state is 8.9 W — factor that into enclosure thermal calculations if the panel is densely populated.