Siemens 3VA1112-3ED32-0AA0 — 125 A MCCB with TM210 trip, line protection duty
The Siemens 3VA1112-3ED32-0AA0 is a SENTRON molded case circuit breaker (MCCB) rated 125 A continuous at 40 °C, with a TM210 thermal-magnetic overcurrent release and 3 poles for three-phase line protection. It carries a breaking capacity of 75.6 kA at 240 V AC, 52.5 kA at 415 V AC, and 32 kA at 440 V AC, so it handles high-fault scenarios typical of industrial distribution panels without cascading upstream. The TM210 trip unit provides fixed thermal and magnetic settings — no adjustment dials — which keeps the part simple for a fixed-load BOM line where the engineer already knows the cable and load current. Rated insulation voltage is 800 V, and the unit is designed for line protection, meaning it sits at the incoming feed or main distribution point in a panel, not on a motor branch. It has no undervoltage release, no communication function, and no ground-fault monitoring — it's a straight thermal-magnetic breaker for straightforward overcurrent and short-circuit protection. Power loss at full load is 28.1 W, a figure to factor into enclosure thermal calculations if the panel is densely packed.
Thermal derating and ambient temperature profile
The 125 A rating holds flat from 40 °C through 50 °C. At 55 °C it derates to 122 A, at 60 °C to 120 A, at 65 °C to 117 A, and at 70 °C to 114 A. That's a gentle slope — about 0.6 A per degree above 50 °C — so a panel running at 60 °C ambient still carries 120 A continuous. The operating temperature range is -25 °C to 70 °C; storage range is -40 °C to 80 °C.
Mounting dimensions and panel fit
The breaker measures 130 mm high, 76.2 mm wide, and 70 mm deep — a standard 3-pole MCCB footprint for DIN-rail or screw-mount panel integration. Width of 76.2 mm (3 inches) matches the typical 3-pole SENTRON slot; depth of 70 mm means it clears most 200 mm deep enclosures with room for wiring gutters. IP40 on the front means protection against tools and wires >1 mm, but not against water — keep it inside a closed panel, not on a washdown floor.