The Siemens 3VA1140-4EF32-0AG0 is a SENTRON 3-pole molded case circuit breaker rated for 40 A continuous current at 40 °C ambient, with a TM240 thermal-magnetic release. Its interrupting ratings climb to 121 kA at 240 V, 75.6 kA at 415 V, 52.5 kA at 440 V, and 11.9 kA at 690 V — numbers that govern its placement in a selective coordination study.
What the interrupting ratings mean for fit
The 121 kA at 240 V and 75.6 kA at 415 V are the SCCR values that determine whether this breaker can be used ahead of a transformer or on a high-capacity bus. A 240 V panel with a 100 kA available fault current is covered; a 480 V panel at 65 kA is not — the 440 V rating of 52.5 kA is the relevant figure for most North American 480/277 V systems. The 690 V rating of 11.9 kA is low enough that this breaker should not be the sole protection on a high-fault 690 V motor control center without a current-limiting upstream device.
Thermal derating and endurance
The 40 A rating holds flat from 40 °C to 50 °C, then derates: 38.4 A at 55 °C, 37.6 A at 60 °C, 36.8 A at 65 °C, and 36 A at 70 °C. In a sealed enclosure with a 60 °C internal ambient, plan for 37.6 A continuous — not the full 40 A.
At 76.2 mm wide, 130 mm tall, and 70 mm deep, this breaker fits a standard 3-pole MCCB footprint on a DIN rail or panel-mount base. The TM240 release is thermal-magnetic, fixed-trip, non-adjustable — so the 40 A rating is set at the factory and cannot be dialed up for temporary overloads.