What this MCCB carries — and what it means for your panel
The Siemens SENTRON 3VA2340-6KP32-0HH0 is a 3-pole molded case circuit breaker (MCCB) rated for line protection, with a continuous current rating of 400 A and a thermal-magnetic trip unit adjustable between 600 A and 4 000 A. The interrupting capacity is voltage-dependent: 242 kA at 240 V, 187 kA at 415 V and 440 V, 121 kA at 500 V, and 7.5 kA at 690 V — so at typical 480Y/277 V distribution levels you have headroom well above most fault-current studies. The breaker includes a shunt trip (STL) for remote opening, two auxiliary switches plus a trip alarm switch (HQ), and a communication function for integration into a monitored distribution system.
Thermal derating — don't size by the nameplate alone
The breaker holds its full 400 A rating up to 50 °C ambient. Above that it derates linearly: 375 A at 55 °C, 350 A at 60 °C, 325 A at 65 °C, and 300 A at 70 °C. If your panel enclosure sits near a hot process line or in a non-conditioned space, the actual continuous current the breaker can carry without nuisance tripping is the derated figure — not the 400 A on the label. Maximum power loss is 96 W, which factors into enclosure thermal calculations.
Physical fit — dimensions and mounting
The breaker measures 248 mm high, 138 mm wide, and 110 mm deep. It mounts on a standard DIN rail or directly to a backplate via the screw terminals. The 138 mm width is the same as the 3VA2 frame common to other SENTRON 3-pole MCCBs in this current class, so if you are swapping a 3VA2116-5JP32-0AE0 or similar, check the depth — the 110 mm depth may differ from older frames and could interfere with enclosure doors or busbar shroud clearance.