The Siemens SENTRON 3VA1140-4EF36-0KC0 is a 3-pole molded case circuit breaker rated for 40 A continuous current at 40 °C ambient, designed for line protection in distribution panels. Its interrupting capacity hits 121 kA at 240 V and 75.6 kA at 415 V — numbers that matter when coordinating with upstream gear for fault clearance under high available fault current. Rated insulation voltage is 800 V, so it handles 690 V systems with margin. The 70 mm depth and 76.2 mm width keep it compact on the DIN rail or panel-mount footprint — no surprises when swapping into an existing MCCB slot.
Current derating and thermal limits
Full 40 A rating holds up to 50 °C. Above that, it derates: 39 A at 55 °C, 38 A at 65 °C, and 37 A at 70 °C. If the panel ambient runs hot, size the load accordingly — the breaker won't nuisance-trip if you respect the curve. Maximum power loss is 10.8 W at rated load — negligible for thermal budgeting in a sealed enclosure, but worth noting if you're packing multiple breakers in a small gland plate.
Breaking capacity across voltage levels
Interrupting capacity drops as voltage rises: 121 kA at 240 V, 75.6 kA at 415 V, 52.5 kA at 440 V, and 11.9 kA at both 500 V and 690 V. The 11.9 kA at 690 V is the limiting figure for high-voltage industrial feeders — verify the available fault current at the point of installation.