What the ratings mean for fit
The Siemens 3VA1112-3EF36-0AD0 is a 3-pole SENTRON molded case circuit breaker (MCCB) rated for 125 A continuous current at 40 °C, with a TM240 thermal-magnetic overcurrent release. That 125 A holds flat from 40 °C up to 50 °C, then derates to 120 A at 55 °C, 117.5 A at 60 °C, 115 A at 65 °C, and 112.5 A at 70 °C — so if your panel ambient runs above 50 °C, the breaker's effective ampacity drops, and you need to account for that in the feeder sizing. The interrupting ratings are given at four voltage levels: 75.6 kA at 240 V, 52.5 kA at 415 V, 32 kA at 440 V, and 10.5 kA at 690 V. For a 480 V panel, the 440 V figure is the closest — 32 kA — which is the SCCR the breaker can clear at that voltage. If your available fault current at the line side exceeds that, you need a current-limiting upstream device or a higher-rated frame. It ships with three HQ auxiliary switches (form C, high-quantity contacts) factory-installed, so you get status feedback without adding a separate accessory block. The TM240 release is fixed — no interchangeable trip unit — so the breaker is sized for a specific load and not meant for field-adjustable ampacity.
Lifecycle and sourcing reality
The rated insulation voltage is 800 V (Ui), and the front face carries IP40 protection — suitable for enclosure mounting where the front is accessible but the bus bars are behind a deadfront. Endurance is listed at 15 000 operations, which is typical for a distribution-grade MCCB in line-protection duty.
Panel integration notes
The breaker measures 130 mm high, 76.2 mm wide, and 70 mm deep — a 3-pole footprint that fits standard Siemens SENTRON mounting plates and busbar systems. No undervoltage release, no shunt trip, no communication module on this variant; if you need those, you are looking at a different order code in the 3VA family. Storage temperature range is -40 °C to 80 °C; operating ambient is -25 °C to 70 °C. The 70 mm depth means it clears most standard enclosure depths without hitting the back panel — useful for retrofit into existing switchboards where space is tight.