MCCB for line protection — 50 A continuous, 3-pole, TM240 release
The Siemens SENTRON 3VA1150-3EF32-0AD0 is a 3-pole molded case circuit breaker (MCCB) rated for 50 A continuous current (Iu) across ambient temperatures from 40 °C to 50 °C, with a TM240 thermal-magnetic overcurrent release. The interrupting ratings scale with system voltage: 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 gives the panel designer headroom for high-fault installations — the 75.6 kA at 240 V covers most North American 240/120 V split-phase or 240 V three-phase services without needing a current-limiting fuse upstream.
Thermal derating and mechanical endurance
Above that, it derates linearly: 48 A at 55 °C, 47 A at 60 °C, 46 A at 65 °C, and 45 A at 70 °C. Mechanical latching endurance is rated at 15,000 operations — typical for an MCCB in a fixed-distribution role where it cycles infrequently (a few times a year for maintenance isolation). Not a switching duty device.
Dimensions are 130 mm height, 76.2 mm width, 70 mm depth — a standard 3-pole MCCB footprint that fits Siemens 3VA panel-mounting accessories and busbar systems. The three auxiliary switches (HQ) mount internally and provide dry contacts for remote status; no separate auxiliary module needed. The TM240 release is fixed (non-adjustable thermal and magnetic), so coordination studies should treat the trip curve as factory-set. No voltage trip or shunt release is fitted — if remote tripping is required, specify a version with the undervoltage or shunt release option.