MCCB for high-fault panel positions
The Siemens SENTRON 3VA1020-3ED42-0DF0 is a 3-pole molded case circuit breaker rated for 32 A continuous current (Iu) with a TM220 thermal-magnetic release. Its interrupting capacity hits 187 kA at 240 V AC and 121 kA at 415 V AC, which means it can clear high-energy faults at the main distribution point without upstream fuses having to open. The line protection version is what you spec for feeder or main breaker duty in a panel, not for motor branch-circuit protection. This MCCB carries an undervoltage release (UVR) as standard, plus one auxiliary switch and one trip alarm switch in the HQ configuration. That UVR coil will drop the breaker if control voltage is lost — a common requirement for emergency-stop circuits or safety interlock schemes. The front face is IP40 rated, so it's fine for a clean indoor panel; no special gasketing needed for dust or splash.
Interrupting ratings across voltages
The interrupting capacity drops as voltage rises: 187 kA at 240 V, 121 kA at 415 V, 76 kA at 440 V, and 17 kA at both 500 V and 690 V. That 17 kA at 690 V is still a solid number for most industrial services — it's the 240 V figure that stands out for high-fault utility feeds. The rated insulation voltage is 800 V, so the breaker is built for 690 V systems with margin.
Current derating and ambient temperature
The 32 A rating holds steady up to 50 °C ambient; at 60 °C it derates to 31 A, and at 70 °C to 30 A. That's minimal thermal drift for a thermal-magnetic MCCB — the TM220 release is well-compensated. If your panel runs hot near the top of the enclosure, you still get full rated current through most of the operating range.
Panel fit and integration
The breaker is 3 inches wide (about 76 mm) and 130 mm tall — standard MCCB footprint for a 3-pole frame at this rating. It mounts on a DIN rail or directly to a backplate with the supplied hardware. The IP40 front protection means it's suitable for a closed panel; no additional sealing is required for normal indoor environments.