What this MCCB carries and where it fits
The Siemens SENTRON 3VA1112-3EF36-0KC0 is a 3-pole molded case circuit breaker (MCCB) rated for 125 A continuous current at 40 °C, with a TM240 thermal-magnetic overcurrent release — meaning the thermal pickup is fixed at 125 A and the magnetic short-circuit trip is calibrated for the TM240 curve. It is the line-protection version, so it is intended for feeder and main breaker duty in distribution panels, not for direct motor starting. Breaking capacity runs 75.6 kA at 240 V, 52.5 kA at 415 V, 32 kA at 440 V, and 10.5 kA at 690 V (–). At 690 V the 10.5 kA figure is the one that governs for high-voltage industrial grids — if your fault current at the panel exceeds that, you need a current-limiting upstream device or a higher-rated frame. Rated insulation voltage Ui is 800 V, so the breaker can be applied in 690 V systems without derating the insulation path. The front face carries IP40 protection — fine for a closed panel, not for washdown zones.
Auxiliaries and releases — what is on board
This unit ships with a shunt trip (STL) auxiliary release, part number 3VA9688-0BL33, and two auxiliary switches HQ. No undervoltage release, no ground-fault monitoring, no communication module, no phase-failure detection (–,). If you need remote trip via undervoltage or a ground-fault alarm, those are separate accessory slots on the 3VA platform — this base unit leaves them open. The trip indicator is not fitted — no mechanical flag on the front to show a trip event. For troubleshooting, you would rely on the shunt trip or the auxiliary contact state.
Thermal derating and ambient limits
Rated continuous current holds at 125 A from 40 °C through 50 °C (–). At 55 °C it drops to 120 A, at 60 °C to 117.5 A, at 65 °C to 115 A, and at 70 °C to 112.5 A (–). If the panel ambient runs above 50 °C, size the upstream conductor and load for the derated value — the breaker will still hold but you lose headroom. Operating temperature range is -25 °C to 70 °C (–); storage range is -40 °C to 80 °C (–). The storage limit governs handling and warehousing, not running conditions.
Panel fit — dimensions and mounting
The 3VA1112-3EF36-0KC0 measures 130 mm high, 76.2 mm wide, and 70 mm deep (–). The 76.2 mm width is a standard 3-pole MCCB footprint — it fits the same DIN-rail or screw-mount hole pattern as other SENTRON 3VA frames. If you are swapping out an older 3VA1112-5EF32-0CA0, the width and depth are identical; the difference is in the release and breaking capacity, not the mounting. Mechanical endurance is rated at 15 000 operations — fine for a main or feeder breaker cycled infrequently, not for a switching duty that sees daily open/close.