What this MCCB delivers and where it fits
The Siemens 3VA1112-3EF36-0AC0 is a SENTRON molded case circuit breaker (MCCB) designed for line protection in distribution panels and industrial switchgear. It carries a TM240 thermal-magnetic overcurrent release, rated 125 A continuously at 40 °C ambient, with no derating needed up to 50 °C — the same 125 A holds at 45 °C and 50 °C, then steps down to 122 A at 55 °C and 114 A at 70 °C. That thermal curve means it can serve a full 125 A load in a well-ventilated enclosure without oversizing the frame. Breaking capacity is 75.6 kA at 240 V, 52.5 kA at 415 V, and 32 kA at 440 V — sufficient for high-fault utility feeds or transformer secondaries in most industrial installations. The 3-pole construction and 800 V rated insulation voltage suit it for 400/480 V three-phase systems common in motor control centers and main distribution boards.
Integration and mounting
The breaker measures 70 mm deep, 76.2 mm wide, and 130 mm high. These dimensions match the standard SENTRON 3VA molded case footprint — it drops into the same panel cutout and bus-bar spacing as other 3VA1 frame breakers. Two built-in auxiliary switches (HQ type) are included, eliminating the need for a separate accessory module for status feedback to a PLC or annunciator panel. Maximum power dissipation is 28.1 W at rated load — a figure to include in thermal calculations for sealed or high-density enclosures. Operating temperature range is -25 °C to 70 °C, storage from -40 °C to 80 °C.