What it is and what it does
The Siemens SENTRON 3VA1220-4EF42-0KH0 is a 4-pole molded case circuit breaker (MCCB) rated for 200 A continuous current (Iu) in line-protection duty, meaning it sits on the feeder side of a distribution panel to protect cables and busbars against overload and short-circuit faults. The TM240 thermal-magnetic release provides fixed overload pickup and magnetic trip coordination — no electronic adjustment, so it's a straight swap-in for legacy panel designs that don't need communication or ground-fault monitoring.
Breaking capacity — what the numbers mean for selectivity
This MCCB delivers 121 kA at 240 V AC, 75.6 kA at 415 V, 25 kA at 440 V, and 11.9 kA at 690 V. Those are the interrupting ratings under short-circuit conditions — the maximum fault current the breaker can safely clear without welding contacts or rupturing the case. For a 415 V distribution board fed by a transformer of 2 MVA or larger, 75.6 kA gives headroom for full selectivity with downstream 25 kA or 36 kA rated breakers, provided the upstream device's let-through energy is coordinated. At 690 V the 11.9 kA rating suits industrial drives or solar combiner panels where fault current is lower.
Thermal derating — how ambient temperature affects the 200 A rating
The 200 A continuous rating holds flat up to 50 °C ambient. Above that, derate linearly: 194 A at 55 °C, 188 A at 60 °C, 182 A at 65 °C, and 176 A at 70 °C. If this breaker lands in a non-ventilated enclosure near transformers or busway, expect to downsize the cable or upsize the breaker frame — a 200 A feeder in a 60 °C panel effectively becomes an 188 A circuit. The rated insulation voltage is 800 V, so the 690 V application is within the dielectric margin.
Auxiliary contacts and shunt trip — what's on board
This variant ships with 2 auxiliary switches plus 1 trip-alarm switch (HQ), and a shunt trip release (STL) integrated — part number 3VA9688-0BL33 for the auxiliary assembly. The shunt trip allows remote tripping via a control signal (e.g., from an emergency-stop relay or PLC output). No undervoltage release, no ground-fault module, no communication function, and no phase-failure detection are fitted. For a simple feeder breaker with remote trip capability, this is the right configuration; if you need undervoltage protection or ground-fault sensing, order a different variant.
Physical fit and environmental limits
Dimensions: 140 mm wide, 158 mm high, 70 mm deep. The 70 mm depth is the body projection from the mounting surface — check that it clears the enclosure door or deadfront. Front face is IP40, so protected against tools and wires >1 mm but not sealed against dust ingress; mount in a panel with a door or cover. Operating temperature range -25 °C to 70 °C, storage from -40 °C to 80 °C. The 4-pole design includes a switched neutral (no N-conductor protection — the neutral pole is switched but not monitored). Latching endurance rated at 15 000 operations, which is typical for a fixed-mounted distribution breaker.