Siemens 3VA1140-3EF32-0KC0 — SENTRON MCCB, 40 A, 3-Pole, Line Protection
The Siemens 3VA1140-3EF32-0KC0 is a SENTRON molded case circuit breaker (MCCB) rated for 40 A continuous current across the 40 to 50 °C ambient range, with a 3-pole construction designed for line protection duty. Breaking capacity reaches 75.6 kA at 240 V, stepping down to 52.5 kA at 415 V, 32 kA at 440 V, and 11.9 kA at both 500 V and 690 V — a curve that tells you this breaker is sized for high-fault commercial and light industrial panels where the available fault current at the secondary of a 480 V transformer can exceed 50 kA. The 800 V rated insulation voltage confirms it can live on a 690 V system without derating the insulation.
Thermal Derating and Panel Integration
At 55 °C the continuous rating drops to 39 A; at 65 °C to 38 A; at 70 °C to 37 A. That derating matters when the breaker sits in a crowded enclosure — a 40 A breaker in a 70 °C cabinet effectively becomes a 37 A device, so the connected load must stay under that reduced figure or the breaker nuisance-trips. Dimensions are 130 mm high, 76.2 mm wide, 70 mm deep — a standard MCCB footprint that fits SENTRON distribution blocks and busbar systems without adapters. The 10.8 W maximum power loss is manageable but should be factored into the enclosure thermal budget if several breakers are ganged.
Built-in Shunt Trip and Auxiliary Switches
This variant includes a shunt trip (STL) release for remote tripping and two HQ auxiliary switches for status feedback to a PLC or annunciator. No undervoltage release is fitted, no ground-fault monitoring, and no communication module — it is a pure line-protection breaker with remote trip capability. The auxiliary switches are rated for the control circuit voltage; wire them to a digital input module to confirm breaker position without relying on a panel indicator light.