What it is and what it does
The Siemens 3VA1063-4ED42-0JA0 is a SENTRON molded case circuit breaker (MCCB) designed for line protection in distribution panels. It carries a 63 A rating at 40 °C ambient with a TM210 thermal-magnetic overcurrent release and an integrated shunt trip (STL) auxiliary release. The 4-pole configuration handles three-phase plus neutral, common for North American and European panel builds.
Breaking capacity and selectivity
Breaking capacity is 121 kA at 240 V, 75.6 kA at 415 V, 52.5 kA at 440 V, and 11.9 kA at both 500 V and 690 V. The 121 kA at 240 V gives headroom for high-fault utility feeds; the 11.9 kA at 690 V is the limiting value for IEC installations. Rated insulation voltage is 800 V, so the breaker is suitable for 690 V line-to-line systems with margin.
Thermal derating and power loss
The 63 A rating holds steady from 40 °C through 50 °C (–). At 55 °C it derates to 62 A, at 60 °C to 61 A, at 65 °C to 60 A, and at 70 °C to 58 A. Maximum power loss is 17.3 W — negligible for panel heat budget but worth noting for sealed enclosures. Operating temperature range is -25 °C to 70 °C; storage range is -40 °C to 80 °C.