The Siemens 3VA1112-5ED32-0CH0 is a SENTRON molded case circuit breaker rated for line protection, carrying 125 A per pole at 40 °C ambient and offering a 187 kA interrupting capacity at 240 V AC — enough to handle high-fault industrial feeders without cascading upstream.
Interrupting capacity — where it fits
The 187 kA at 240 V AC drops to 121 kA at 415 V AC and 75.6 kA at 440 V AC, then to 17 kA at 500 V and 690 V. That means it's sized for high-available-fault systems on the low-voltage side of a distribution transformer — think main feeder or large subfeed in a 480 V panel where the bolted-fault current is well above 100 kA.
Thermal performance and derating
Above that it derates linearly: 122 A at 55 °C, 120 A at 60 °C, 117 A at 65 °C, and 114 A at 70 °C. If your panel ambient runs at 55 °C, plan for 122 A continuous — not the nameplate 125. Maximum power loss is 30.6 W — modest for a 125 A frame, but enough to matter in a sealed, non-ventilated enclosure. Account for that heat in your thermal budget.
The 3-pole width of 76.2 mm (3 inches) is standard for a 125 A frame MCCB — it will fit existing Siemens SENTRON mounting feet and busbar adapters without panel modification. The storage limit is the handling limit, not the running limit.