MCCB for line protection with UVR
The Siemens SENTRON 3VA1112-5EF36-0BA0 is a 3-pole molded case circuit breaker (MCCB) rated for 125 A at 40 °C, designed for line protection in industrial distribution panels. Its TM240 thermal-magnetic overcurrent release handles moderate overloads and short circuits, while the built-in undervoltage release (UVR) drops the breaker if supply voltage falls below the dropout threshold — a common requirement for safety circuits and motor feeder disconnects. The interrupting capacity is the standout: 187 kA at 240 V AC, 121 kA at 415 V, and still 17 kA at 690 V. That puts this breaker in the high-fault tier — suitable for main feeders or sub-distribution near large transformers where available fault current is severe. The 800 V rated insulation voltage confirms it can be used on 690 V systems with proper coordination.
Thermal derating and panel fit
Rated current holds flat at 125 A up to 50 °C ambient; above that it derates gradually to 114 A at 70 °C (the maximum operating temperature). In a crowded panel with poor airflow, factor in the 30.6 W max power loss when sizing cabinet cooling. Dimensions are 130 mm height × 76.2 mm width × 70 mm depth — a standard 3-pole MCCB footprint that fits most Siemens SENTRON panelboards and third-party enclosures with matching busbar centers. The 70 mm depth leaves clearance for wiring gutters and gland plates.