63 A continuous, flat across the curve
The Siemens 3VA2063-6JP42-0AA0 is a SENTRON molded case circuit breaker rated for 63 A continuous from 40 °C all the way up to 70 °C — no derating to track across the operating range. That simplifies panel design when the enclosure runs warm. Four-pole construction with an ETU550 electronic trip unit. The li adjustable from 95 A to 756 A, and the lg response value is set at 0.5 s. That gives you selectivity headroom downstream without sacrificing fault clearing speed. Breaking capacity runs 242 kA at 240 V, 187 kA at 415 V and 440 V, 121 kA at 500 V, and 3 kA at 690 V. At 240 V that's enough to handle most utility transformer secondaries without a current-limiting fuse upstream.
Panel fit and integration
Footprint is 140 mm wide by 181 mm tall by 86 mm deep. That 86 mm depth — about 3.4 in — means it clears most standard enclosure back-panels without a sub-panel extension. The IP40 front face keeps dust out of the trip-unit compartment in a clean indoor panel. Communication function is built in, and the optional motor drive (listed as a factory extension) allows remote open/close for automated load shedding or emergency shutdown sequences.