What the interrupting ratings mean for your panel
The Siemens 3VA1120-5EF36-0HH0 is a SENTRON molded case circuit breaker (MCCB) rated for line protection in distribution panels. Its interrupting capacity hits 187 kA at 240 V, 121 kA at 415 V, 75.6 kA at 440 V, and 17 kA at 690 V — these are the fault currents it can safely clear without welding contacts or rupturing the case. For a 20 A frame, that is high-interrupting capability; it means this breaker can sit upstream of a transformer or a bus tap where available fault current is substantial, and still coordinate with downstream devices without needing a current-limiting fuse ahead of it. The TM240 thermal-magnetic release provides overload protection via a bimetal element and short-circuit protection via a magnetic solenoid. Rated continuous current Iu is 20 A, and the breaker holds that rating from 40 °C through 50 °C ambient — no derating needed in a typical 40 °C panel. Above 50 °C the curve begins to step down: 19.2 A at 55 °C, 18.8 A at 60 °C, 18.4 A at 65 °C, and 18 A at 70 °C. If the breaker lives in a hot enclosure near other heat sources, that derating table tells you exactly where the continuous current limit sits.
Auxiliary contacts and shunt trip — what is on board
This variant ships with two auxiliary switches plus one trip alarm switch (HQ type) — that gives you status feedback for both the breaker position and the tripped condition on a single device. The integrated shunt trip (STL) allows remote tripping via a control voltage; the auxiliary release order code for the trip unit is 3VA9688-0BL30. There is no undervoltage release, no communication module, no phase-failure detection, and no ground-fault monitoring on this configuration — it is a straightforward thermal-magnetic breaker with remote-trip capability and contact status, suited for a standard distribution feeder where you do not need the additional protection functions.
Physical fit and environmental limits
The 3VA1120-5EF36-0HH0 measures 130 mm high, 76.2 mm wide, and 70 mm deep — a 3-pole frame that fits standard Siemens SENTRON panel mounting. Front protection is IP40, meaning tools or fingers cannot reach live parts from the front, but the breaker is not sealed against water ingress; it belongs inside a panel enclosure. Operating temperature range is -25 °C to 70 °C; storage range is -40 °C to 80 °C. The latching endurance is rated at 15,000 cycles — that is the mechanical life for the switching mechanism under no-load or low-load conditions.