400 A continuous, 154 kA interrupting — line protection for high-fault panels
The Siemens 3VA1340-6EF42-0AA0 is a 4-pole SENTRON molded case circuit breaker rated 400 A continuous at 40 °C, with a TM240 thermal-magnetic overcurrent release. It delivers 154 kA breaking capacity at 415 V AC — enough to clear severe fault currents on utility-scale distribution or industrial main feeders without cascading upstream. The breaker maintains full 400 A rating up to 50 °C ambient; above that it derates linearly to 367 A at 70 °C. That thermal curve matters for panels packed tight or installed near heat sources — the 92.1 W max power loss also needs ventilation consideration in the enclosure. Front IP40 protection keeps dust and tools out of the mechanism, but the body is not sealed — mount inside a rated enclosure for washdown or outdoor duty.
Breaking capacity across voltage tiers
At 240 V the breaker interrupts 220 kA; at 440 V it holds 154 kA; at 500 V it drops to 121 kA; at 690 V it still clears 17 kA. That voltage-dependent curve is typical for MCCBs — the arc extinction energy scales with system voltage, so the rating drops. For DC networks, the manual specifies separate derating values.
Panel fit and integration
Dimensions: 248 mm high, 184 mm wide, 110 mm deep. The 4-pole frame occupies roughly 30% more DIN space than a 3-pole equivalent — verify the panel cutout and busbar spacing before committing the layout. No undervoltage release or communication module on this variant; it is a straight line-protection device.