What this MCCB carries on the line side
The SENTRON 3VA1140-5EF32-0DC0 is a 3-pole molded case circuit breaker (MCCB) built for line protection — primary-side fault isolation in distribution panels, motor control centers, and switchboards. Rated 40 A at 40 °C with a symmetrical breaking capacity of 187 kA at 240 V AC, it clears high-fault scenarios without cascading upstream. At 415 V AC it still interrupts 121 kA, and at 690 V AC it holds 17 kA, so it's sized for industrial supply voltages where fault currents are substantial.
Thermal derating and real-world current
The 40 A rating holds flat from 40 °C up to 50 °C. Above that it derates gradually: 39 A at 55 °C and 60 °C, 38 A at 65 °C, and 37 A at 70 °C. If the panel ambient runs warm — say a crowded enclosure near a drive or transformer — the actual continuous current the breaker can carry drops by a few amps. The rated insulation voltage is 800 V, giving headroom for 690 V systems.
Auxiliaries and releases built in
This unit ships with an undervoltage release (UVR) fitted — it trips the breaker if control voltage drops below a set threshold, standard for emergency-stop or undervoltage protection schemes. It also carries 2 auxiliary switches (HQ type) for status feedback to a PLC or indication lamp. No communication function or ground-fault monitoring on this variant; it's a straightforward line-protection MCCB with the aux contacts and UVR integrated at the factory.
Panel fit — dimensions and integration
The breaker measures 130 mm high, 76.2 mm wide, and 70 mm deep — a 3-pole MCCB footprint that fits standard Siemens SENTRON mounting plates and busbar systems. The 76.2 mm width (3 inches) is a common pole spacing; you can land it in an existing panel that was laid out for a 3VA1-series frame without re-drilling. Power loss is 13.3 W maximum, which matters for thermal calculations in a sealed enclosure.