MCCB for line protection – 320 A continuous, 76 kA interrupting at 415 V
The Siemens 3VM1332-4GD42-0AA0 is a SENTRON molded case circuit breaker (MCCB) designed for line protection in distribution panels. It carries 320 A continuously at 40 °C and interrupts up to 76 kA at 415 V — enough headroom for most industrial service-entrance or feeder applications where fault currents are high. The 4-pole construction suits three-phase systems with a fully rated neutral, common in North American and European panel builds. The TM210 overcurrent release provides fixed thermal-magnetic protection; no trip indicator or undervoltage release is built in, so external accessories are needed if those functions are required.
Thermal derating and panel integration
At 40 °C the breaker is rated 320 A, and it holds that rating through 50 °C. Above 55 °C it derates linearly to 292 A at 70 °C. In a sealed enclosure or high-ambient machine cabinet, that derating curve (–) governs the real load it can carry. The IP40 front protection means the breaker face is protected against tools and wires >1 mm — standard for a deadfront panel — but not against water ingress, so it belongs inside a dry enclosure. Dimensions are 184 mm wide, 248 mm tall, and 110 mm deep; verify the mounting footprint against the panel cutout before wiring.