Ratings and interrupting performance
The Siemens SENTRON 3VA1040-3ED36-0BA0 is a 3-pole molded case circuit breaker rated 40 A continuous at 40 °C ambient, with a TM210 thermal-magnetic overcurrent release. Its interrupting capacity reaches 75.6 kA at 240 V and 52.5 kA at 415 V — figures that define the maximum fault current it can safely clear without upstream coordination failure. At 440 V the rating drops to 32 kA, and at 500 V and 690 V it holds at 7.5 kA. The rated insulation voltage is 800 V, so the breaker is suitable for 480 V and 600 V class systems within those interrupting limits. The TM210 release provides thermal protection for overloads and magnetic (instantaneous) protection for short-circuits. The breaker includes an undervoltage release (UVR) as standard — when control voltage drops below the dropout threshold, the UVR trips the breaker, preventing automatic reclosure on an undervoltage condition. This is typical for motor feeder circuits where a momentary loss of supply should not cause an uncontrolled restart.
Thermal derating and panel integration
The 40 A rating holds up to 50 °C ambient. Above that, derating applies: 38.4 A at 55 °C, 37.6 A at 60 °C, 36.8 A at 65 °C, and 36 A at 70 °C. For a panel running at 60 °C, the breaker is effectively a 37.6 A device — plan the load accordingly. The 3VA frame width is 76.2 mm (3 in), depth 70 mm (2.76 in), height 130 mm (5.12 in). That footprint matches the standard SENTRON 3VA mounting pattern, so it drops into existing DIN-rail or panel-mount cutouts without re-drilling. Maximum power loss is 13.3 W. In a sealed enclosure with multiple breakers, that heat adds up — account for it in the thermal budget. The operating temperature range is -25 °C to 70 °C; storage range is -40 °C to 80 °C.