RCCB for 4-wire systems — 80 A, Type A, 100 mA trip
The Siemens SENTRON 5SV3447-6 is a 4-pole residual-current circuit breaker (RCCB) rated 80 A at 40 °C ambient, tripping on 100 mA residual current. Type A detection catches pulsating DC as well as sinusoidal AC faults — the usual spec for circuits with single-phase rectifiers, switching power supplies, or VFD front ends. Instantaneous design means no intentional delay; it clears fast on a ground fault. Rated 230/400 V AC, 50 Hz, with a short-circuit current rating of 10 kA. The 4-pole block handles three-phase plus neutral in a single module — common for main incoming protection in sub-distribution boards or machine supply panels. Mounts on DIN rail (REG), occupies 4 modular width units (72 mm). Installation depth is 70 mm. Mounting position any — no derating needed for horizontal or inverted orientation. IP20 with the distribution board installed and conductors connected.
Thermal derating and ambient limits
The 80 A rating holds at 40 °C. Above that, derate: 77.57 A at 45 °C, 74.59 A at 50 °C, 70.22 A at 55 °C, 64.47 A at 60 °C, 57.35 A at 65 °C, 48.84 A at 70 °C. If the panel runs hot — say, a packed enclosure near a motor drive — check the actual cabinet temperature against this curve before sizing the feeder. Operating ambient range -25 °C to 45 °C; storage range -40 °C to 75 °C. The storage limit governs handling and shipping, not running.