The Siemens 3VA1050-3ED42-0KA0 is a 3VA1 IEC frame 100 molded case circuit breaker with a 50 A fixed thermal-magnetic overload (Ir=50 A) and fixed short-circuit protection set at 10× In (Ii=500 A). Its breaking capacity class N delivers 25 kA Icu at 415 V AC, which means it can safely interrupt fault currents up to that level on a 400 V distribution panel without upstream cascading — a solid fit for commercial and light industrial switchboards where the available fault current stays under that threshold.
What the ratings mean for fit
The 4-pole configuration with unprotected N conductor suits three-phase + neutral systems where the neutral does not require overcurrent protection — common in TN-S or TN-C-S networks. The integrated shunt trip (STL) accepts 220-250 V DC or 208-277 V AC, allowing remote tripping from a safety relay or emergency-stop circuit. The nut keeper kit simplifies panel mounting by retaining the hardware during installation, a detail that speeds up assembly on a DIN-rail or backplate.