125 A MCCB with 187 kA interrupting capacity
The Siemens SENTRON 3VA1112-5EF36-0JC0 is a 3-pole molded case circuit breaker rated 125 A at 40 °C, sized for line protection in distribution panels. It carries a 187 kA interrupting capacity at 240 V — that's the fault-clearing headroom for high-available-fault-current service entrances or subfeeds where the utility transformer is close. At 415 V it still breaks 121 kA, and at 690 V it holds 17 kA, so the SCCR follows the voltage curve. The 800 V rated insulation voltage means it's specced for 690 V systems with margin. Max power loss runs 28.1 W, which factors into enclosure thermal rise calculations.
Fit and panel integration
Footprint is 76.2 mm wide by 130 mm tall by 70 mm deep — standard 3-pole MCCB width for a 125 A frame. The 70 mm depth is shallower than many older frames, which helps in shallow enclosures or gland-plate clearance. It ships with 2 HQ auxiliary switches and a shunt trip release (STL) built in, so you don't need to add those as separate accessories for remote trip or status feedback. The basic switch assembly is order code 3VA11125EF360AA0. No undervoltage release and no ground-fault monitoring on this variant — those are separate order codes if needed.
Thermal derating and operating range
Rated 125 A 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 (–). Operating ambient range is -25 °C to +70 °C (–); storage range is -40 °C to +80 °C (–). If the panel ambient runs hot, the continuous current rating drops — size the upstream conductor and downstream load for the derated value, not the 125 A nameplate.