Siemens 3VA1150-4EF32-0CC0 — 50 A MCCB for Line Protection
The Siemens SENTRON 3VA1150-4EF32-0CC0 is a 3-pole molded case circuit breaker (MCCB) designed for line protection in distribution panels. It carries a continuous current rating of 50 A at 40 °C and holds that rating through 50 °C, derating to 49 A at 55 °C and 45 A at 70 °C — useful to know when the breaker sits in a warm enclosure alongside other heat sources. Breaking capacity is the headline: 121 kA at 240 V AC, 75.6 kA at 415 V, 52.5 kA at 440 V, and 11.9 kA at both 500 V and 690 V. That 121 kA figure at 240 V means it handles high available fault current on the secondary side of a typical 480 V–240 V step-down transformer without needing a current-limiting fuse upstream. The 75.6 kA at 415 V covers most European industrial distribution panels. Rated insulation voltage is 800 V, so the breaker is suitable for 690 V line-to-line systems with margin. Power loss at rated current is 17.1 W maximum — a figure to factor into enclosure thermal calculations when grouping several breakers.
Built-in Undervoltage Release and Auxiliary Switches
This variant ships with an undervoltage release (UVR) factory-installed — the design of the auxiliary release is listed as undervoltage release (UVR). That means the breaker trips automatically when supply voltage drops below a threshold, protecting downstream equipment from brownout conditions or preventing automatic restart after a power loss. The auxiliary switch complement is two HQ-style auxiliary switches, providing status feedback for the open/closed position without needing an add-on module. The breaker does not include a ground-fault monitoring version, a communication function, a trip indicator, or a voltage trigger. It is a straightforward line-protection MCCB with the UVR as the main accessory — no extra frills, which keeps the BOM clean for standard distribution duty.
Panel Fit and Dimensions
Dimensions: 130 mm height, 76.2 mm width, 70 mm depth. The 70 mm depth is shallow enough for most 200 mm deep enclosures with room for wiring gutters. Width at 76.2 mm (3 inches) is standard for a 3-pole MCCB in this frame size — fits the typical DIN-rail or panel-mount footprint without surprises. Operating temperature range is -25 °C to 70 °C; storage range is -40 °C to 80 °C. Suitable for unconditioned electrical rooms or outdoor-rated enclosures within those limits.