63 A MCCB with 75.6 kA interrupting capacity — what the ratings mean for your panel
The Siemens SENTRON 3VA1163-3EF36-0JH0 is a 3-pole molded case circuit breaker rated 63 A at 40 °C ambient, with a maximum power loss of 17.3 W. That 63 A holds flat through 50 °C — only starts derating at 55 °C (62 A) and drops to 58 A by 70 °C, so it carries its full rating in most ventilated enclosures without forced cooling. The interrupting capacity hits 75.6 kA at 240 V, 52.5 kA at 415 V, and still delivers 11.9 kA at 690 V — that's serious fault-current headroom for a 63 A frame, meaning it can sit downstream of a large transformer without needing a current-limiting fuse upstream for coordination. This is a line-protection design — no ground-fault module, no communication module, no undervoltage release. What it does carry is a shunt trip (STL) and a full complement of auxiliary switching: two auxiliary contacts plus a separate trip alarm switch (HQ). That's enough for remote status indication and a shunt-trip emergency-off circuit without adding external relay logic. Rated insulation voltage is 800 V, so it's comfortable on 480/277 V or 600 V systems with margin.
Physical fit and wiring — panel integration notes
Dimensions are 130 mm high, 76.2 mm wide, 70 mm deep. That 70 mm depth is the key number for shallow enclosures or tight gland-plate clearance — it's shallower than many MCCBs in this current class, which often run 85–100 mm deep. The 76.2 mm width (3 inches) is standard for a 3-pole frame in this range; it occupies three 25 mm DIN positions if mounted on a DIN rail adapter, or bolts directly to the mounting plate. Operating temperature range is -25 °C to 70 °C; storage range is -40 °C to 80 °C.