Siemens SENTRON 3VA1112-3EF32-0AG0 — 125 A MCCB, Line Protection
The Siemens 3VA1112-3EF32-0AG0 is a 3-pole molded case circuit breaker from the SENTRON 3VA series, designed for line protection with a TM240 thermal-magnetic overcurrent release. It carries a rated current of 125 A at 40 °C and delivers a breaking capacity of 75.6 kA at 240 V AC, stepping down to 52.5 kA at 415 V and 32 kA at 440 V — figures that cover most industrial distribution panels in North America and Europe. The TM240 release means the thermal element tracks a 240 A frame, with the magnetic pickup set at a fixed multiple of the 125 A rating. That combination suits feeder circuits where you need a high short-circuit withstand but don't want nuisance trips on motor inrush — the magnetic hold is high enough to ride through a starting transient.
Breaking Capacity and Selectivity
Breaking capacity drops to 11.9 kA at both 500 V and 690 V — still adequate for most 480/277 V and 600 V panels, but at 690 V you're near the limit for high-fault industrial grids. The rated insulation voltage is 800 V, so the breaker itself is insulated for that level; the interrupting rating is what governs the installation's SCCR. For selectivity coordination downstream of a larger 3VA frame, the TM240's I²t curve is published in Siemens' selectivity tables. The 125 A rating at 40 °C derates to 114 A at 70 °C — a 9 % drop — so if the panel ambient runs hot, size the upstream transformer or bus accordingly.
Physical Fit and Auxiliary Switching
The breaker measures 130 mm high, 76.2 mm wide, and 70 mm deep — a standard 3-pole MCCB footprint that drops into SENTRON panelboards and most DIN-rail adapters. The supplied basic switch carries order code 3VA11123EF320AA0, with one auxiliary contact and one trip-alarm switch (HP type) factory-installed. Power loss is 28.1 W maximum at rated current — within the range for a 125 A frame, but worth checking against the enclosure's thermal dissipation if you're packing multiple breakers in a sealed cabinet.
Environmental and Lifecycle
The trip indicator is present (a mechanical flag on the front), and there is no undervoltage release, no ground-fault monitoring, and no communication function on this variant — it's a straight thermal-magnetic line-protection breaker.