Siemens 3VA1112-5MH36-0AA0 — 125 A SENTRON MCCB for Motor and Starter Protection
The Siemens 3VA1112-5MH36-0AA0 is a SENTRON molded case circuit breaker (MCCB) designed specifically for starter protection, with a TM120M thermal-magnetic overcurrent release and a 3-pole configuration. Rated 125 A continuously at 40 °C, it holds that same rating through 50 °C, then derates to 122 A at 55 °C, 120 A at 60 °C, 117 A at 65 °C, and 114 A at 70 °C — so in a warm panel near the upper ambient limit, you lose about 9 % of your headroom. Breaking capacity is voltage-dependent: 187 kA at 240 V AC, 121 kA at 415 V, 75.6 kA at 440 V, and 7.5 kA at both 500 V and 690 V. That 187 kA at 240 V is high enough for most secondary-side transformer feeds or large motor branch circuits with high available fault current.
Panel Fit and Integration
The 3VA1112-5MH36-0AA0 measures 130 mm high, 76.2 mm wide, and 70 mm deep — a standard 3-pole MCCB footprint that fits most DIN-rail or screw-mounted panel layouts without surprises. Rated insulation voltage is 800 V, so it's comfortable in 480 V and 600 V class systems. IP40 on the front means it's protected against tools and small wires entering the enclosure, but not against moisture — keep it inside a sealed panel, not in a washdown zone.