The Siemens SENTRON 3VA1112-3EF32-0DH0 is a 3-pole molded case circuit breaker rated for line protection. It carries 125 A at 40 °C and delivers a breaking capacity of 75.6 kA at 240 V, 52.5 kA at 415 V, and 32 kA at 440 V — enough headroom for most industrial distribution panels where fault current runs high. The 125 A frame means it protects feeders or large branch circuits, and the 3-pole design handles three-phase loads straight out of the box.
What the ratings mean for fit
The 125 A rating at 40 °C is the continuous current the breaker can carry without tripping in a 40 °C ambient. If your panel runs hotter — say 55 °C — the breaker derates to 122 A, and at 70 °C it's 114 A. That matters when you're packing breakers tight in a closed enclosure; you need to check the actual ambient at the breaker location, not just the load. Breaking capacity is the big one: 75.6 kA at 240 V means this breaker can safely interrupt a fault current up to that level without welding its contacts or exploding. At 415 V it's still 52.5 kA, and at 690 V it holds at 11.9 kA. That covers most industrial services up to 690 V, but if your transformer is big enough to push fault current past 52.5 kA at 415 V, you need a higher-rated breaker upstream. The breaker includes an undervoltage release (UVR) and comes with two auxiliary switches plus a trip alarm switch. The UVR trips the breaker if the control voltage drops below a threshold — common for emergency-stop circuits or to prevent reclosure after a power loss. The auxiliary switches let you wire status back to a PLC or indicator lamp. Rated insulation voltage is 800 V, so the internal clearances and creepage are designed for systems up to that voltage, even though the breaking capacity is rated at lower levels. Storage temperature range is -40 °C to 80 °C, operating is -25 °C to 70 °C — fine for most indoor panel environments but not for direct outdoor exposure without an enclosure.
Panel integration
The breaker measures 130 mm high, 76.2 mm wide, and 70 mm deep. Those dimensions are for the base unit without the rotary handle or external accessories. It mounts on a DIN rail or can be screw-mounted to a backplate. The width of 76.2 mm (3 inches) is standard for a 3-pole MCCB in this class — it fits alongside other SENTRON breakers in a common distribution panel without odd gaps.