SENTRON 3VM1220-5MH32-0AA0 — 200 A MCCB with TM120M Release
The Siemens SENTRON 3VM1220-5MH32-0AA0 is a 3-pole molded case circuit breaker (MCCB) rated for 200 A continuous at 40 °C, designed for distribution and motor branch protection in industrial panels. It carries an interrupting capacity of 187 kA at 240 V AC, 121 kA at 415 V, 76 kA at 440 V, and 30 kA at 500 V — giving you headroom for high-fault installations without cascading upstream gear. The TM120M thermal-magnetic release provides fixed overload and short-circuit protection curves, with no ground-fault or undervoltage release options on this variant — it's a straight-ahead line or feeder breaker. Insulation voltage is rated 800 V, so it's comfortable on 480/277 V and 600 V systems with margin.
Current Derating and Thermal Management
The breaker holds a full 200 A up to 50 °C ambient, then derates linearly: 194 A at 55 °C, 188 A at 60 °C, 182 A at 65 °C, and 176 A at 70 °C. Maximum power loss is 42 W — account for that heat in a sealed enclosure with other high-current devices. Operating range is -25 °C to 70 °C; storage from -40 °C to 80 °C. Front protection is IP40 — fine for a clean panel interior, but not for washdown. Dimensions are 105 mm wide × 158 mm high × 70 mm deep, fitting standard 3-pole MCCB panel cutouts.