Breaking capacity and selectivity headroom
The 3VA1050-4ED36-0KC0 is a 3-pole molded case circuit breaker from the Siemens SENTRON family, rated for line protection duty. Its interrupting capacity varies sharply with system voltage: 121 kA at 240 VAC, 75.6 kA at 415 VAC, 52.5 kA at 440 VAC, and 11.9 kA at both 500 VAC and 690 VAC. That 121 kA at 240 V gives you substantial headroom for high-fault panels where the available short-circuit current is near the upper end of the distribution transformer's capability — a common scenario in North American 240 V delta or 277/480 V wye services with large upstream transformers. The 75.6 kA at 415 V covers most European industrial grids. At 690 V the breaker still holds 11.9 kA, enough for light industrial loads on that voltage tier. The rated insulation voltage is 800 V, so the breaker's internal clearances and creepage are designed for 690 V systems with margin. That matters when you are coordinating with upstream switchgear that may have a lower rated impulse withstand — the 3VA series maintains coordination down to the listed let-through energy.
Thermal derating and continuous current
Rated 50 A from 40 °C through 50 °C ambient — no derating needed in a standard 40 °C panel environment. At 55 °C it drops to 49 A, at 60 °C to 48 A, at 65 °C to 46 A, and at 70 °C to 45 A. That is a gentle slope: roughly 0.2 A per degree above 50 °C. If your panel internal ambient runs at 60 °C (common in sealed enclosures with multiple heat sources), you still have 48 A of continuous capacity. The maximum operating temperature is 70 °C, and storage range is -40 °C to 80 °C. Power loss at rated load is 14.6 W maximum. That is moderate for a 50 A MCCB — the heat dissipated inside the panel is manageable without forced ventilation in most enclosures, but worth factoring into the thermal budget if the panel is densely packed.
Integration and auxiliary options
The breaker ships with a shunt trip release (STL) and two auxiliary switches (HQ configuration). The shunt trip allows remote tripping via a control voltage — essential for emergency-stop circuits or supervisory shutdown sequences. The two auxiliary switches provide status feedback (open/closed/tripped) to a PLC or annunciator panel. No undervoltage release is fitted; if you need UVR for undervoltage protection, that is a different variant. Dimensions are 130 mm height, 76.2 mm width, 70 mm depth. The 76.2 mm width is 3 inches — a standard 3-pole MCCB footprint that fits most DIN-rail or panel-mount bases in the SENTRON range. The 70 mm depth is shallow enough for 200 mm deep enclosures with clearance for wiring.