What it is and what it does
The Siemens 3VA1332-5MH32-0CE0 is a SENTRON molded case circuit breaker (MCCB) rated for 320 A continuous, 3-pole construction, designed for starter protection in motor control centers and distribution panels. It carries a breaking capacity of 187 kA at 240 V AC, 121 kA at 415 V and 440 V, 75.6 kA at 500 V, and 11.9 kA at 690 V — meaning it can safely interrupt fault currents up to those levels without cascading upstream, which is critical for selectivity coordination in high-fault installations. Rated insulation voltage is 800 V.
Key ratings and what they mean for fit
The 320 A rating is non-derated up to 50 °C ambient; at 55 °C it carries 313 A, at 60 °C 306 A, at 65 °C 299 A, and at 70 °C 292 A — so in a warm enclosure you lose about 1% per degree above 50 °C, which is typical for this class and worth factoring into your thermal budget. Maximum power loss is 82.6 W — not negligible in a crowded panel; plan for ventilation or derate adjacent devices if you're stacking breakers. Operating temperature range is -25 °C to 70 °C, storage from -40 °C to 80 °C, so it handles cold storage and warm enclosures without issue.
Integration and wiring
The breaker ships with an undervoltage release (UVR) and four auxiliary switches (HQ design) pre-installed — that saves you a wiring pass if your safety circuit requires a shunt trip or status feedback. Dimensions are 248 mm high, 138 mm wide, 110 mm deep — standard 3-pole MCCB footprint for a 320 A frame; it mounts on a DIN rail or directly to a backplate, so it drops into most existing SENTRON or third-party panels without re-drilling. No communication module onboard (no Modbus or PROFIBUS), and no ground-fault monitoring — those are separate add-ons if your spec requires them.