63 A C-curve MCB for 400 V AC distribution
The Siemens SENTRON 5SJ3663-7 is a 4-pole miniature circuit breaker (3P+N) rated at 63 A with a C tripping characteristic, breaking 4.5 kA at 400 V AC per EN 60898 and IEC 60947-2. That 4.5 kA symmetrical rating means it safely clears a bolted fault up to that level without upstream devices needing to coordinate — critical for a panel feeding a motor control center or a warehouse shuttle aisle where a stalled crane blocks an entire racking bay. The 63 A C-curve handles moderate inrush from small motors or transformers without nuisance tripping, but the 4.5 kA SCCR is the number that governs selectivity with the upstream feeder breaker. Mounts on standard DIN rail; the 70 mm installation depth leaves room for gland plates and wiring troughs in a packed enclosure.
Conductor termination and environmental range
Accepts solid or stranded conductors from 0.75 mm² up to 25 mm² — sized for the 63 A feed and downstream subfeeds without needing reducers. Sealable terminals (yes) and touch protection built in, so a panel builder can wire it and close the cover without exposed live parts. Ambient temperature range spans -40 to +75 °C (operating -20 to +45 °C), with periodic tolerance to +55 °C at 95% humidity — relevant if the panel sits near a washdown zone or in an unconditioned warehouse mezzanine. Vibration resistance tested to 50 m/s² at 25–150 Hz and 60 m/s² at 10–150 Hz per IEC 60068-2-6, so it holds up on a machine frame or in a mobile substation.