What it is and what it does
The Siemens 3VM1150-3GE42-0AA0 is a SENTRON molded case circuit breaker (MCCB) rated for line protection. It carries a continuous current of 50 A at 40 °C through all four poles, with a TM220 thermal-magnetic release — fixed thermal and magnetic trip settings, no electronic adjustment. The 76 kA breaking capacity at 240 V AC drops to 53 kA at 415 V, 32 kA at 440 V, and 12 kA at 500 V, so the interrupting rating must be checked against the available fault current at the point of installation. The 690 V rated insulation voltage (Ui) supports 480Y/277 V and 600 V delta systems comfortably.
Mounting and panel fit
The breaker measures 70 mm deep by 101.6 mm wide by 130 mm high. The 101.6 mm (4 in) width is standard for a 4-pole MCCB in this class.
Thermal derating and power loss
The breaker holds 50 A continuously up to 50 °C ambient. Above that, it derates linearly: 49 A at 55 °C, 48 A at 60 °C, 46 A at 65 °C, 45 A at 70 °C. Maximum power loss is 15 W at rated load — negligible for panel heat calculation but worth noting if the breaker is packed tightly with other heat sources. Storage range is -40 °C to 80 °C; operating ambient -25 °C to 70 °C.