SENTRON 3VA1 — line protection MCCB with TM240 release
The Siemens SENTRON 3VA1163-6EF32-0AD0 is a 3-pole molded case circuit breaker (MCCB) rated for line protection duty, fitted with a TM240 thermal-magnetic overcurrent release. It carries a continuous current rating of 63 A at 40 °C, derating to 58 A at 70 °C, and a rated insulation voltage of 800 V. The interrupting capacity reaches 220 kA at 240 VAC, stepping down to 154 kA at 415 V and 121 kA at 440 V — figures that give selectivity headroom in high-fault panels. This MCCB is designed for line protection (not motor or feeder protection), meaning the TM240 release curve is tailored for cable and busbar protection in distribution boards. The 3-pole construction with no undervoltage release and no ground-fault monitoring keeps the wiring simple for straightforward main-breaker or branch-feeder roles.
Breaking capacity and selectivity planning
The 220 kA breaking capacity at 240 V is the headline number, but the real-world selectivity story is in the 154 kA at 415 V and 121 kA at 440 V — typical for 400 V class distribution. At 500 V and 690 V the capacity drops to 17 kA, so for 480 V or 600 V panels this breaker needs upstream coordination with a current-limiting device. The 63 A frame with these interrupting ratings suits it for main incoming breakers in sub-distribution boards or as a high-fault branch protector.
Thermal derating and panel integration
The 63 A rating holds flat from 40 °C to 50 °C, then drops one amp per 5 °C step to 58 A at 70 °C. In a sealed, uncooled enclosure at 55 °C ambient, expect 62 A continuous — a 1.6 % derating. The maximum power loss of 17.3 W is modest for a 63 A frame, so internal cabinet heating from the breaker alone is manageable. Dimensions of 130 mm height, 76.2 mm width, and 70 mm depth fit standard Siemens 3VA1 mounting footprints; the auxiliary switch bay accepts up to 3 HQ auxiliary switches.