MCCB for line protection — 50 A, 187 kA at 240 V
The Siemens 3VA1150-5EF32-0AF0 is a 3-pole SENTRON molded case circuit breaker rated for line protection duty, carrying a continuous current Iu of 50 A across its full ambient range up to 50 °C, then derating to 45 A at 70 °C. Its TM240 thermal-magnetic release provides fixed overload and short-circuit protection without undervoltage or ground-fault accessories. The interrupting capacity reaches 187 kA at 240 V, 121 kA at 415 V, and 75.6 kA at 440 V — figures that govern selectivity coordination in high-fault panels.
What the ratings mean for panel fit
The 187 kA SCCR at 240 V means this breaker can safely interrupt faults up to that level without upstream cascading — critical for transformer-fed switchboards where available fault current is high. The 800 V rated insulation voltage (Ui) confirms it is suitable for 480 V and 600 V class systems with margin. The IP40 front protection means it is dust-protected on the operator face but not sealed against hose-down; mount inside a panel enclosure rated for the environment. Mechanical endurance of 15,000 cycles suits applications with moderate switching frequency — typical for distribution feeder protection rather than motor-starting duty where higher cycle counts are needed. The 1 auxiliary switch + 1 trip alarm switch (HQ configuration) provides status feedback and fault indication to a PLC or annunciator without an external relay.
Integration and mounting
The 3VA1150-5EF32-0AF0 occupies 76.2 mm width, 130 mm height, and 70 mm depth — a standard MCCB footprint for DIN-rail or screw-mount panel integration. The 3-pole form factor matches existing busbar and lug kits for the SENTRON 3VA platform. Verify lug torque and wire bending space per the device manual when laying out the gland plate.