What this MCCB carries
The Siemens SENTRON 3VA2340-5JQ32-0CC0 is a 3-pole molded case circuit breaker rated 400 A at 40 °C, with a full-scale setting of 400 A and an initial trip threshold of 80 A. It's designed for line protection and includes an undervoltage release (UVR) plus two HQ auxiliary switches. The interrupting capacity hits 187 kA at 240 V, 121 kA at 415 V and 440 V, 75.6 kA at 500 V, and 7.5 kA at 690 V — so it handles high-fault utility feeds and transformer secondaries without cascading upstream. Thermal derating is published across the full range: 400 A continuous through 50 °C, then 375 A at 55 °C, 350 A at 60 °C, 325 A at 65 °C, and 300 A at 70 °C. That's the curve you need if the breaker lives in a non-air-conditioned switchroom or near a transformer.
Panel fit and footprint
Dimensions are 248 mm high, 138 mm wide, 110 mm deep. That 110 mm depth is the key clearance number for shallow backpanels or enclosure-mounted bus stacks — measure your gutter depth before committing the BOM line. Maximum power loss is 98.5 W, so factor that into your enclosure thermal budget if the panel is sealed or has limited venting.
Auxiliaries and communication
Comes with a built-in undervoltage release (UVR) and two HQ auxiliary switches. The UVR trips the breaker when control voltage drops below a set threshold — standard for emergency-stop chains or undervoltage protection schemes. Communication function is integrated, so it can report status or accept remote commands over the SENTRON bus system. The basic switch variant is 3VA2340-5JQ32-0AA0 — same frame, same trip unit, without the auxiliaries and UVR. If you're stocking a bare breaker for spares and adding auxiliaries in the field, that's the SKU to cross-reference.