MCCB for line protection — 50 A, 3-pole, with UVR and aux switches
The Siemens SENTRON 3VA1150-5EF36-0CC0 is a 3-pole molded case circuit breaker (MCCB) designed for line protection, rated 50 A at 40 °C with a thermal derating curve that holds 50 A through 50 °C, then steps down to 49 A at 55 °C, 48 A at 60 °C, 46 A at 65 °C, and 45 A at 70 °C — so in a 65 °C panel ambient the breaker still carries 46 A continuously without tripping. Interrupting capacity is 187 kA at 240 V, 121 kA at 415 V, 75.6 kA at 440 V, and 17 kA at both 500 V and 690 V — the 187 kA figure at 240 V means this breaker can safely clear a fault on a high-capacity 240 V distribution transformer without upstream fuses needing to clear first. Rated insulation voltage is 800 V, so the internal clearances and creepage are sized for 690 V systems with margin.
Built-in undervoltage release and auxiliary switch complement
This variant ships with an undervoltage release (UVR) factory-fitted — when control voltage drops below the dropout threshold, the UVR trips the breaker, which is standard for safety circuits where loss of control power must open the main contacts. It also carries two auxiliary switches HQ (high-rupturing-capacity type) for remote status indication — one normally-open and one normally-closed contact pair that can be wired into a PLC input module or a panel lamp circuit to confirm the breaker position. The basic switch ordered separately is 3VA11505EF360AA0 — the factory-assembled variant here avoids field-fitting the UVR and aux switches, which saves panel-build labour and eliminates the risk of mis-wiring the release coil.
Thermal management and panel fit
Maximum power loss is 17.1 W at rated load — for a 3-pole breaker in a sealed enclosure this heat must be accounted for in the thermal budget; the derating curve above 55 °C already reflects internal heating. Dimensions are 130 mm height, 76.2 mm width, and 70 mm depth (2.76 in).
Active production — no lifecycle concern
Operating temperature range is -25 °C to +70 °C, storage -40 °C to +80 °C — the storage range exceeds operating, which governs handling during transport and warehouse idle periods.