Line protection breaker with high interrupting capacity
The Siemens SENTRON 3VA1140-3EF32-0CC0 is a 3-pole molded case circuit breaker (MCCB) designed for line protection in distribution panels and industrial switchgear. It carries a continuous rated current of 40 A at 40 °C, with only minor derating as ambient rises — still 37 A at 70 °C. That thermal stability means it holds its rating across typical panel internal temperatures without oversizing. Breaking capacity is the headline number here: 75.6 kA at 240 V, 52.5 kA at 415 V, and still 32 kA at 440 V. For a 40 A frame, those are high-interrupt ratings — the breaker can clear a bolted fault on a large transformer secondary or a motor-control center bus without upstream fuses. The 800 V rated insulation voltage confirms it is built for 400/480 V class systems with headroom. The unit includes an undervoltage release (UVR) as standard, which drops the breaker on loss of control voltage — a common requirement for safety circuits or emergency-stop chains. Two auxiliary switches (HQ design) are integrated for status feedback to a PLC or panel indication. No communication module or ground-fault monitoring is fitted on this variant.
Panel fit and integration
The breaker measures 130 mm high, 76.2 mm wide, and 70 mm deep. Mounting is via rear DIN rail or screw-mount plate. Maximum power loss is 13.3 W at rated load — negligible for thermal management in a ventilated panel, but worth noting for sealed enclosures where internal temperature rise must be calculated.