What this MCCB carries
The Siemens SENTRON 3VA1112-3EF32-0BH0 is a 3-pole molded case circuit breaker rated for 125 A continuous at 40 °C, with a full-current rating holding steady up to 50 °C before a gentle thermal derating curve kicks in — 122 A at 55 °C, 120 A at 60 °C, 117 A at 65 °C, and 114 A at 70 °C. That means for most panel environments below 50 °C, you get the full 125 A without headroom math. Interrupting capacity runs 75.6 kA at 240 V AC, 52.5 kA at 415 V, 32 kA at 440 V, and 11.9 kA at both 500 V and 690 V — so the SCCR you can claim downstream depends on which voltage tap you're feeding. Rated insulation voltage is 800 V, which covers 480/277 V and 600 V class systems with margin. This is a line-protection design (not motor-protection curve), so it's the right call for feeder and distribution panels where you need selective coordination against downstream faults. The built-in undervoltage release (UVR) lets you drop the breaker on loss of control voltage — handy for emergency-stop chains or undervoltage lockout schemes.
Auxiliary and alarm contacts
Factory-fitted with 2 auxiliary switches plus 1 trip alarm switch (HQ type). That gives you two independent status signals for PLC or SCADA input, plus a dedicated alarm contact that closes only on a fault trip — no need to add a separate shunt trip or auxiliary module for basic monitoring.
Panel fit and environment
Footprint is 130 mm high, 76.2 mm wide, 70 mm deep — a standard 3-pole MCCB envelope that drops into most SENTRON 3VA panelboards and distribution blocks without re-drilling the mounting plate. Operating temperature range is -25 °C to 70 °C, storage from -40 °C to 80 °C, so it's fine for unheated electrical rooms or outdoor enclosures with heaters. Maximum power dissipation is 30.6 W — a number to factor into enclosure thermal calculations if you're packing multiple breakers in a sealed box. Trip indicator is present, so a quick visual scan of the panel face tells you which breaker tripped without opening the door.