Line protection MCCB with TM240 release
The Siemens SENTRON 3VA1150-5EF32-0BH0 is a 3-pole molded case circuit breaker rated for line protection, carrying a continuous current Iu of 50 A and a rated insulation voltage Ui of 800 V. Its interrupting capacity reaches 187 kA at 240 V, 121 kA at 415 V, 75.6 kA at 440 V, and 17 kA at 690 V — figures that govern selectivity coordination in a distribution panel. The TM240 overcurrent release is a thermal-magnetic type, fixed at 50 A, with no electronic adjustment. Auxiliary contact configuration is 2 auxiliary switches plus 1 trip alarm switch (HQ variant), and the breaker ships with an undervoltage release (UVR) fitted. The integrated auxiliary trip is order code 3VA9608-0BB11. No communication function, phase failure detection, or ground fault monitoring is built in — this is a straightforward thermal-magnetic MCCB for standard distribution duty.
Thermal derating and panel fit
The breaker holds its full 50 A rating 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 ambient runs hot — say, a packed enclosure near a drive — the 70 °C derated figure of 45 A is the working limit. Operating range is -25 °C to 70 °C; storage range is -40 °C to 80 °C. Footprint is 130 mm high, 76.2 mm wide, 70 mm deep. Front protection is IP40. The 76.2 mm width is three standard 25.4 mm pole pitches — it occupies the same DIN-rail or mounting-plate slot as any 3-pole MCCB in this class. The undervoltage release and auxiliary switch block add depth behind the front cover; verify clearance to the gland plate or back panel before wiring.