Line protection MCCB with thermal-magnetic release
The Siemens SENTRON 3VA1150-3EF32-0KA0 is a 3-pole molded case circuit breaker rated for line protection, carrying a continuous current Iu of 50 A per the datasheet. It uses a TM240 thermal-magnetic overcurrent release — the fixed thermal element handles overloads, and the magnetic trip responds to short-circuit events. The interrupting ratings are specified at multiple voltage levels: 75.6 kA at 240 V, 52.5 kA at 415 V, 32 kA at 440 V, and 10.5 kA at 690 V. That spread tells you the available fault current the breaker can safely clear drops as system voltage rises; at 690 V the 10.5 kA rating still covers most industrial distribution panels. The rated insulation voltage is 800 V.
Thermal derating and panel fit
The 50 A rating holds flat from 40 °C through 50 °C ambient. Above that, derating is gradual: 48 A at 55 °C, 47 A at 60 °C, 46 A at 65 °C, and 45 A at 70 °C. If the panel internal temperature runs near 60 °C, the effective continuous current drops to 47 A — factor that into the load schedule. The enclosure dimensions are 70 mm deep, 76.2 mm wide, and 130 mm high. Front-face protection is IP40, meaning tools or fingers won't contact live parts from the front, but the breaker is not sealed against dust ingress. The latching endurance is rated at 15 000 operations.
Integrated shunt trip and auxiliary options
This variant includes a shunt trip (STL) auxiliary release, order code 3VA9688-0BL33, for remote tripping via a control voltage. There is no undervoltage release, no auxiliary contact block, and no communication function on this version. No phase failure detection or ground fault monitoring is integrated. The trip indicator is not present — visual trip status would need an external auxiliary contact. If remote signaling is required, the auxiliary contact slot is available as a separate order.