The Siemens SENTRON 3VM1340-4GD42-0AA0 is a 4-pole molded case circuit breaker rated 400 A at 40 °C, with a TM210 thermal-magnetic overcurrent release designed for line protection. It breaks up to 121 kA at 240 V and 76 kA at 415/440 V, so it handles high-fault utility feeds or large transformer secondaries without cascading upstream. The 800 V rated insulation voltage means it's suited for 480 V and 600 V class systems with margin.
Current ratings and thermal behavior
Rated 400 A continuous from 40 °C through 50 °C ambient, then derates to 392 A at 55 °C, 384 A at 60 °C, 376 A at 65 °C, and 367 A at 70 °C (–). That's a 33 A drop from 50 °C to 70 °C — about 8% — so if the panel runs hot near the top of the enclosure, you still hold most of the rating. Power loss at full load is 92 W maximum, which matters for heat buildup in a sealed cabinet.
Lifecycle and sourcing
Listed as current production. No phase-out or last-time-buy notice on this order code. Sourced and quoted to order against an RFQ through independent distribution; availability and current pricing confirmed at quote time.
Physical fit and panel integration
Measures 110 mm deep, 184 mm wide, 248 mm tall (–). The 4-pole body at 184 mm width is standard for this frame size — verify the existing busbar or lug kit spacing if retrofitting into a panel cut for a narrower 3-pole breaker. Front face carries IP40 protection, so it's fine for a clean indoor panel but not washdown areas. Operating range is -25 °C to 70 °C (–); storage from -40 °C to 80 °C (–).