What this MCCB is and what it carries
The Siemens SENTRON 3VA2340-5HN32-0CA0 is a 3-pole molded case circuit breaker (MCCB) rated for 400 A continuous current, designed for line protection in distribution panels. It carries a 187 kA interrupting capacity at 240 V AC and 121 kA at 415 V AC, so it handles high-fault utility feeds without cascading upstream. The breaker includes an undervoltage release (UVR) as the auxiliary release — that's the -0CA0 suffix telling you it drops the load when control voltage falls below a set threshold, which matters for motor-control safety circuits or emergency-stop chains.
Derating and thermal reality
The 400 A rating holds at ambient up to 50 °C. Above that it steps down: 385 A at 55 °C, 370 A at 60 °C, 355 A at 65 °C, 340 A at 70 °C. If your panel runs hot — say a packed enclosure near a furnace line — the 55 °C derate is where you start losing headroom. The maximum power loss is 98.5 W, which factors into enclosure thermal calculations. Operating range is -25 °C to 70 °C; storage range is -40 °C to 80 °C.
Panel fit and dimensions
The breaker measures 248 mm high, 138 mm wide, 110 mm deep. That's a standard SENTRON 3VA form factor — mounts on a DIN rail or direct-panel plate. The 110 mm depth means it clears most 200 mm deep enclosures with room for rear busbars. No auxiliary switch fitted (the -0CA0 variant leaves that off), but the undervoltage release is built in.