What it is and what it does
The Siemens 3VA1220-4EF42-0JA0 is a SENTRON molded case circuit breaker (MCCB) rated for 200 A continuous current on a 4-pole frame, with a TM240 thermal-magnetic overcurrent release and an integrated shunt trip (STL) for remote tripping. It's a line-protection device — no ground-fault monitoring, no undervoltage release, no auxiliary contacts — built for straightforward overcurrent and short-circuit protection in distribution panels. Breaking capacity is the headline here: 121 kA at 240 V, 75.6 kA at 415 V, 25 kA at 440 V, and 11.9 kA at 690 V. That 121 kA figure at 240 V means it can safely interrupt a fault current up to that level without welding contacts or cascading failure upstream — critical for high-fault installations like transformer secondaries or large motor control centers. The 200 A rating holds flat from 40 °C through 50 °C, then derates to 176 A at 70 °C, so panel ambient temperature matters for sizing.
Integration and mounting
This MCCB mounts on a DIN rail or directly to a backplate in a standard distribution panel. The 4-pole frame takes up 140 mm width on the rail, with a 158 mm height and 70 mm depth — check your enclosure depth before committing. Front IP40 protection means it's splash-safe from the front but not sealed; keep it inside a cabinet for washdown environments. The shunt trip (order code 3VA9688-0BL32 for the release itself) allows remote tripping via a control signal, useful for emergency-stop circuits or load-shedding schemes.