What it is and what it does
The Siemens SENTRON 3VA1220-6MH32-0AB0 is a 3-pole molded case circuit breaker (MCCB) rated for a continuous current of 200 A at 40 °C, designed specifically for starter protection — meaning it is built to protect motor starters and their associated wiring from overcurrents and short circuits, not just as a general distribution breaker. The TM120M thermal-magnetic overcurrent release provides inverse-time overload protection and instantaneous magnetic trip for short-circuit faults, so the breaker coordinates with a contactor and overload relay in a motor-starting circuit. At 240 V it interrupts up to 220 kA; at 415 V that drops to 154 kA, at 440 V to 75.6 kA, at 500 V to 30 kA, and at 690 V to 4.5 kA — the full range matters when the available fault current at the panel is known.
Thermal derating and ambient conditions
The breaker carries its full 200 A up to 50 °C ambient without derating. At 55 °C the rating drops to 194 A, at 60 °C to 188 A, at 65 °C to 182 A, and at 70 °C to 176 A. If the panel sits near a furnace or in a hot mill environment, use the 55 °C or 60 °C column to size the breaker for the actual load — ignoring the derate risks nuisance tripping. Operating range is -25 °C to 70 °C; storage range is -40 °C to 80 °C. Maximum power loss at rated current is 42 W.
Panel fit and integration
Dimensions are 105 mm wide, 158 mm high, and 70 mm deep — a standard 3-pole MCCB footprint for a SENTRON 3VA frame. The breaker mounts on a DIN rail or can be screw-fixed to a backplate. It ships with two auxiliary switches (HP design) factory-installed, so you get status feedback without adding a separate accessory block. No undervoltage release, no ground-fault monitoring, no communication module on this variant — it is a straight thermal-magnetic starter protector.