What the ratings mean for fit
The Siemens 3VA1112-3GD42-0AA0 is a SENTRON molded case circuit breaker (MCCB) rated for 125 A continuous current at 40 °C, with the TM210 thermal-magnetic overcurrent release. That 125 A figure holds flat from 40 °C 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 you lose about 9% of capacity by 70 °C. The interrupting ratings are 75.6 kA at 240 V, 52.5 kA at 415 V, 32 kA at 440 V, and 11.9 kA at both 500 V and 690 V. That 75.6 kA at 240 V is the headline number for high-fault service-entrance applications; the 52.5 kA at 415 V covers most European industrial distribution. Four poles with 100% N-conductor protection mean the neutral is switched and protected at full ampacity — no derating for the neutral path. Rated insulation voltage is 800 V, and the maximum DC operational voltage is 600 V, so this breaker can serve DC circuits up to that level — consult the 3VA device manual for DC switching-power values. The front face carries IP40 protection, meaning it's protected against tools and small wires but not against water ingress; mount it inside a panel with a higher enclosure rating.
Panel integration and footprint
The 3VA1112-3GD42-0AA0 measures 130 mm high, 101.6 mm wide, and 70 mm deep. That 70 mm depth is the dimension from the mounting surface to the front of the breaker — important for gland-plate clearance and door swing in a shallow enclosure. The 101.6 mm width (4 inches) for a 4-pole MCCB is standard for the SENTRON 3VA platform; verify the mounting hole pattern against your existing backplate or DIN-rail adapter if retrofitting.
Key specifications at a glance
Maximum power loss is 28.1 W — relevant for thermal budgeting inside a sealed enclosure. Operating temperature range is -25 °C to 70 °C; storage range is -40 °C to 80 °C. The breaker has no communication function and no ground-fault monitoring version. An optional motor drive is available as a product extension.