Siemens 3VA1112-5EF36-0DH0 — 125 A SENTRON MCCB with Undervoltage Release
The Siemens 3VA1112-5EF36-0DH0 is a SENTRON molded case circuit breaker (MCCB) rated for 125 A continuous at 40 °C, 3-pole, designed for line protection in distribution and motor control center applications. Its interrupting capacity reaches 187 kA at 240 V AC, 121 kA at 415 V, 75.6 kA at 440 V, and 17 kA at 500 V and 690 V — figures that govern selectivity and fault-clearing capability in high-fault industrial networks. The breaker carries a rated insulation voltage of 800 V and includes an undervoltage release (UVR) as the auxiliary release, plus a factory-fitted auxiliary switch block with 2 auxiliary switches and 1 trip alarm switch (HQ). Maximum power loss is 30.6 W at rated current.
Thermal Derating and Ambient Operating Range
The 125 A rating holds from 40 °C through 50 °C ambient. Above that, derating is linear: 122 A at 55 °C, 120 A at 60 °C, 117 A at 65 °C, and 114 A at 70 °C. The operating ambient range is -25 °C to +70 °C, with storage from -40 °C to +80 °C. For a panel running warm — say, 55 °C inside the enclosure — the usable current is 122 A, not the full 125 A. That 3 A difference matters when sizing for a continuous load near the breaker's nameplate.
Physical Integration and Auxiliary Wiring
Dimensions are 130 mm height, 76.2 mm width, 70 mm depth — a 3-pole MCCB footprint that fits standard SENTRON panel cutouts and busbar systems. The auxiliary switch block (2 aux + 1 trip alarm HQ) and the undervoltage release are pre-configured at the factory; no field assembly of internal accessories is required. The UVR coil wiring must be routed to a separate control voltage source — it is not self-powered from the breaker's line side.