What this MCCB is and what it protects
The Siemens SENTRON 3VA1050-4ED36-0JC0 is a 3-pole molded case circuit breaker (MCCB) rated for 50 A at 40 °C, designed for line protection in distribution panels and feeder circuits. Its breaking capacity reaches 121 kA at 240 V AC, 75.6 kA at 415 V, and 52.5 kA at 440 V, which means it can safely interrupt high fault currents across common low-voltage distribution voltages — critical for selectivity coordination in a main or sub-main breaker position. At 690 V the breaking capacity is still 11.9 kA, covering industrial supply voltages where standard MCBs would not hold. The rated insulation voltage of 800 V gives headroom for 690 V systems without derating the internal clearances. Maximum power loss is 14.6 W, which matters for thermal management inside a sealed or high-density enclosure.
Integrated releases and auxiliary switching
This variant includes a shunt trip release (STL) for remote tripping via a control signal, and two auxiliary switches HQ for status feedback to a PLC or indication lamp — no separate add-on modules needed for basic remote indication. The shunt trip allows the breaker to be opened from a safety circuit, emergency stop, or fire alarm panel without an operator at the handle. No undervoltage release is fitted, so the breaker will not automatically trip on loss of control voltage — intentional for applications where a momentary dip should not drop a critical feeder.
Current derating and thermal limits
The breaker carries 50 A continuously up to 50 °C ambient, then derates to 49 A at 55 °C, 48 A at 60 °C, 46 A at 65 °C, and 45 A at 70 °C. Operating temperature range is -25 °C to +70 °C; storage range is -40 °C to +80 °C, so it survives cold warehouses and hot shipping containers without damage.
Dimensions and panel fit
Width is 76.2 mm (3 in), depth 70 mm (2.76 in), height 130 mm (5.12 in) — a standard 3-pole MCCB footprint that fits existing SENTRON panel cutouts and busbar systems without re-drilling.