What this MCCB carries — and what it doesn't
The Siemens 3VA1120-4EF36-0KA0 is a SENTRON molded case circuit breaker designed for line protection — a 3-pole MCCB with a TM240 thermal-magnetic overcurrent release and an integrated shunt trip (STL) for remote opening. Rated 20 A continuously at 40 °C, it holds that rating flat through 55 °C, then derates to 19 A at 60 °C and 70 °C — so in a warm panel you lose 1 A, not half the rating. Breaking capacity runs 121 kA at 240 V, 75.6 kA at 415 V, 52.5 kA at 440 V, and 11.9 kA at both 500 V and 690 V. That 121 kA at 240 V is the headline number, but the 75.6 kA at 415 V is the one that matters for most three-phase commercial and light industrial panels — it clears high-fault scenarios without cascading upstream.
Shunt trip — what it buys you
The shunt trip (STL) release lets you open the breaker remotely — fire alarm, emergency stop, or a PLC-driven safety sequence can fire the trip coil and kill the load without someone walking the panel. No undervoltage release on this variant, so it won't drop out on a brownout; the shunt trip is strictly a commanded-open device. Power loss is 12 W max, which is modest for a 20 A MCCB with a shunt trip holding in.
Panel fit — dimensions and integration
The 3VA1120-4EF36-0KA0 measures 130 mm high, 76.2 mm wide, and 70 mm deep — a standard 3-pole MCCB footprint that drops into SENTRON distribution panels and most DIN-rail or mounting-plate layouts. No communication function onboard, so no backplane wiring or bus coupler to account for; just the line and load lugs plus the shunt trip control wires.