Siemens 5SV3646-8 SENTRON Selective RCCB — 4-Pole, 63 A, 300 mA
The Siemens 5SV3646-8 is a SENTRON selective residual current circuit breaker (RCCB), 4-pole, type A, rated at 63 A with a 300 mA residual operating current and 400 V AC supply. Selective design means it coordinates with downstream RCCBs — only the faulted branch trips, keeping the rest of the distribution board live. That's the key difference from a standard RCCB: it introduces a deliberate time delay so the device closest to the fault clears first.
The 300 mA sensitivity is the trip threshold for earth leakage. Type A detects both sinusoidal AC residual currents and pulsating DC residual currents — covers most modern electronic loads (VFDs, switched-mode supplies) that generate pulsed leakage. The selective characteristic (short-time delayed) means this RCCB is installed upstream as a main switch, not at the final circuit. It gives downstream 30 mA RCCBs time to trip first, so a ground fault on one outlet doesn't darken the whole panel.