What this MCCB is and what it does
The Siemens SENTRON 3VA1063-3ED32-0BC0 is a 3-pole molded case circuit breaker (MCCB) rated for line protection — meaning it is designed to protect cables and busbars against overload and short-circuit in distribution panels, not motor or generator circuits. At 40 °C ambient it carries 63 A continuously, derating to 58 A at 70 °C. The interrupting rating hits 75.6 kA at 240 V AC, 52.5 kA at 415 V, and still holds 7.5 kA at 690 V — enough for high-fault industrial service where the upstream transformer can deliver serious current.
Ratings that decide the fit
The 63 A frame is rated at 100 % of its nameplate from 40 °C up to 50 °C; above that it follows a published derating curve — 62 A at 55 °C, 61 A at 60 °C, 60 A at 65 °C, and 58 A at 70 °C. If your panel ambient runs hot, you need to account for that reduction rather than relying on the 63 A label. The rated insulation voltage of 800 V gives headroom for 690 V systems without de-rating the dielectric. Breaking capacity is specified across five voltage levels: 75.6 kA at 240 V, 52.5 kA at 415 V, 32 kA at 440 V, and 7.5 kA at both 500 V and 690 V. That 7.5 kA at 690 V is the limiting figure for 690 V distribution — verify your available fault current at the point of installation does not exceed that. Power loss at rated current is 19.8 W maximum — relevant for thermal budgeting inside a sealed or tightly packed enclosure. The MCCB includes an undervoltage release (UVR) as standard and is fitted with two auxiliary switches (HQ type) for remote status indication.
Mounting and integration
The 3VA1063-3ED32-0BC0 is a fixed-mount MCCB with a 76.2 mm (3 in) width, 130 mm (5.12 in) height, and 70 mm (2.76 in) depth. It occupies three pole spaces on a DIN rail or panel-mount base. The front-facing terminals accept standard lug or busbar connections. No communication module or ground-fault monitoring is built in — those are external add-ons if required.