The Siemens 3VA1120-3EF36-0HH0 is a 3-pole IEC frame 160 molded case circuit breaker (MCCB) from the 3VA1 series, rated at 20 A with a breaking capacity of 25 kA at 415 V (class N). It carries a TM240 thermal-magnetic trip unit with adjustable overload protection (Ir = 14...20 A) and short-circuit protection (Ii = 8...16 × In). A shunt trip (STL) rated for 12–30 V DC or 24 V AC at 50/60 Hz is built in, along with two auxiliary switches (HQ) and one trip alarm switch (HQ).
What the ratings mean for fit
The 25 kA Icu at 415 V is the ultimate breaking capacity — the breaker can safely interrupt a fault at that level once and remain functional afterward. Class N puts it in the standard-performance tier for IEC 60947-2, suited for most commercial and light industrial distribution panels where fault currents stay below that threshold. The TM240 trip unit gives you a thermal-adjustment range of 14–20 A (Ir) via a dial, letting you match the breaker to the actual load without swapping the whole device; the magnetic short-circuit pickup is fixed at 8–16 times In (160–320 A), which covers motor-start inrush and cable protection. The shunt trip allows remote tripping from a PLC or emergency-stop circuit, and the two auxiliary plus one alarm switch provide status feedback — open/closed for the aux, tripped for the alarm — so a panel PLC knows exactly what state the breaker is in.
Where it fits in a panel
This breaker mounts on a DIN rail or panel plate inside a distribution or motor control center. The clamp-type terminals accept copper or aluminum conductors; no special lug kit is needed for standard panel wiring. The shunt trip coil draws power from a separate control circuit — verify the 12–30 V DC or 24 V AC supply is present and fused appropriately, because a loss of that supply disables remote trip capability. The auxiliary and alarm switches are wired back to a digital input module on the PLC for status monitoring.