SCCR and thermal derating — the real numbers that decide fit
The 3VA1120-5EF36-0AF0 is a 3-pole SENTRON molded case circuit breaker rated for 20 A continuous current (Iu) with a TM240 thermal-magnetic overcurrent release. Its breaking capacity is the headline: 187 kA at 240 V, 121 kA at 415 V, 75.6 kA at 440 V, and 17 kA at 690 V. That SCCR range covers most industrial LV distribution panels up to 690 V without needing a current-limiting upstream device — the breaker itself handles the fault. Thermal derating is flat from 40 °C to 50 °C at the full 20 A, then drops to 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 your panel ambient runs above 50 °C, the continuous load needs to be sized against the derated figure, not the nameplate 20 A. Operating temperature range is -25 °C to 70 °C; storage range is -40 °C to 80 °C. The IP40 front protection means it's fine for a clean indoor panel — not for washdown or outdoor exposure without an enclosure.
Auxiliary contacts and trip indication
Comes fitted with one auxiliary switch and one trip alarm switch (HQ version). That gives you both a status signal for the breaker position and a separate alarm for a fault trip — useful for remote monitoring or PLC input without adding external relays. The trip indicator is present on the front, so a walk-by visual check confirms the breaker state. No undervoltage release, no communication function, no phase failure detection, and no ground fault monitoring on this variant. If you need those, this isn't the order code — the 3VA family has options for electronic releases and communication modules, but this one is a straight line-protection thermal-magnetic breaker.
Physical fit — panel integration note
Dimensions: 130 mm height, 76.2 mm width, 70 mm depth. That 76.2 mm width is a standard 3-pole MCCB footprint — 3 modules at 25.4 mm each — so it fits a standard DIN-rail or panel-mount cutout without surprises. The 70 mm depth means it clears most shallow enclosures, but verify the gland plate clearance if your panel is tight on depth.