What it is and what it does
The Siemens 3VA1050-3ED42-0KH0 is a 4-pole IEC frame 100 circuit breaker with a 50 A fixed thermal-magnetic (TM210) release, rated for a breaking capacity of 25 kA at 415 V AC (class N). That 25 kA Icu means it can safely interrupt a fault current up to that level without welding contacts or cascading failure upstream — critical for selective coordination in a distribution panel.
Built-in accessories for control and signaling
Factory-fitted with a shunt trip (STL) rated 220–250 V DC and 208–277 V AC, plus two auxiliary switches (HQ) and one trip alarm switch (HQ). The shunt trip lets a remote PLC or E-stop circuit open the breaker independently of the thermal-magnetic trip — standard for emergency-off or load-shedding schemes. The auxiliary and alarm switches provide status feedback (open/closed/tripped) back to the control system, all in one package.
DIN-rail panel fit
Mounts on standard DIN rail inside the enclosure. The 4-pole footprint and integrated shunt trip occupy the same slot as a standard 4-pole MCCB — no extra panel space for external control relays.