Siemens 3VA1112-5GE42-0AA0 — 125 A, 4-Pole SENTRON MCCB for Line Protection
The Siemens 3VA1112-5GE42-0AA0 is a 4-pole SENTRON molded case circuit breaker (MCCB) rated 125 A at 40 °C, designed for line protection in distribution panels. It carries a TM220 thermal-magnetic overcurrent release and provides 100% N-conductor protection, meaning the neutral pole is fully rated and switched with the phase poles — no derating needed for unbalanced loads or harmonic-rich circuits. The interrupting ratings span the common industrial voltages: 187 kA at 240 V AC, 121 kA at 415 V AC, 75.6 kA at 440 V AC, and 17 kA at both 500 V and 690 V AC. That 187 kA at 240 V is the headline number — it tells you this breaker can sit at the service entrance on a high-fault panel without needing a current-limiting fuse upstream. Rated insulation voltage is 800 V, and the maximum operating voltage is 690 V AC. Power loss at rated load is 28.1 W — a useful figure for enclosure thermal calculations when packing several breakers in a single panel.
Current Ratings Across Temperature
The 125 A rating holds flat from 40 °C through 50 °C. Above that it derates gradually: 122 A at 55 °C, 120 A at 60 °C, 117 A at 65 °C, and 114 A at 70 °C. If your panel ambient runs above 50 °C, size the continuous load against the derated value — not the 40 °C nameplate.
Physical Fit and Environment
Dimensions: 130 mm height, 101.6 mm width, 70 mm depth. That 70 mm depth is the key panel clearance number — it fits standard distribution board depths without forcing a deeper enclosure. Front-side IP40 protection means it's splash-proof on the face but not sealed; keep it inside a rated enclosure for washdown areas. Operating temperature range is -25 °C to 70 °C; storage range is -40 °C to 80 °C. The storage minimum is the one to watch if the breaker sits in an unheated warehouse before installation — it's fine down to -40 °C, but let it stabilize above -25 °C before closing the circuit.