What this 3VA1120-3EF36-0AD0 is and what it does
The Siemens SENTRON 3VA1120-3EF36-0AD0 is a 3-pole molded case circuit breaker (MCCB) rated for line protection — meaning it sits upstream of feeders and branch circuits, not on a motor starter or a drive input. Its job is to clear faults fast and stay selective with downstream devices. Rated continuous current Iu is 20 A at 40 °C ambient, and it holds that rating flat through 50 °C — at 55 °C it derates to 19.2 A, at 60 °C to 18.8 A, at 65 °C to 18.4 A, and at 70 °C to 18 A. That thermal curve matters when the breaker lives in a warm cabinet next to other heat sources; the 20 A nameplate is only good if your panel ambient stays at or below 50 °C. Breaking capacity is the real selector here: 75.6 kA at 240 V, 52.5 kA at 415 V, 32 kA at 440 V, and 10.5 kA at 690 V. Those numbers tell you this breaker can interrupt fault currents up to those levels without welding contacts or venting gas — critical for SCCR compliance on a 480 V panel where available fault current might hit 50 kA. The overcurrent release is a TM240 — a thermal-magnetic fixed-trip unit with an adjustable long-time delay (tr max 1 s). No electronic trip, no communication, no ground-fault or phase-failure detection. It is a straightforward thermal-magnetic breaker for standard distribution duty where you do not need metering or remote signaling.
Physical fit and panel integration
Dimensions: width 76.2 mm, height 130 mm, depth 70 mm. That width is a standard 3-pole MCCB footprint — it will drop into most panel-mounted breaker bases or DIN-rail adapters meant for SENTRON 3VA frames. Front protection is IP40, so it is splash-safe in a typical enclosure but not rated for washdown. Comes with 3 auxiliary switches HQ (high-quantity switching) built in — these give you remote status of the breaker position (ON/OFF/TRIPPED) without needing a separate accessory. No undervoltage release, no voltage trigger, no shunt trip on this variant; if you need those, you are looking at a different order code in the 3VA family.
Lifecycle and sourcing reality
For a BOM freeze or a replacement order, the 3VA1120-3EF36-0AD0 is the exact 20 A TM240 variant you need if the spec calls for a 3-pole line-protection MCCB with auxiliary switches and no electronic trip. If your panel was built around the 3VA1010-2ED32-0JA0 (a different frame size and release), the mounting and bus-bar spacing may differ — verify the foot-print before assuming a drop-in swap.