The Siemens SENTRON 3VA1120-4EF36-0JA0 is a 3-pole molded case circuit breaker (MCCB) rated for line protection, carrying 20 A continuously at 40 °C and delivering a 121 kA interrupting capacity at 240 V AC — enough to handle high-fault utility feeds without cascading upstream.
Breaking capacity and coordination
At 415 V the breaker still interrupts 75.6 kA, dropping to 52.5 kA at 440 V and 11.9 kA at 500 V and 690 V. That gives you selectivity headroom for a 400 V distribution board — the MCCB clears a bolted fault before a downstream 18 kA MCB sees it.
Thermal-magnetic release and shunt trip
The overcurrent release is a TM240 thermal-magnetic type — fixed thermal and magnetic trip, no electronic adjustment. An integrated shunt trip (STL) allows remote tripping via a control signal, useful for emergency-stop or undervoltage schemes. Rated insulation voltage is 800 V, and maximum power loss hits 12 W at full load — plan for that heat in a dense panel.
Physical fit and panel integration
Dimensions are 76.2 mm wide, 130 mm tall, and 70 mm deep — a standard 3-pole MCCB footprint that mounts on a DIN rail or direct-panel bolting. The 70 mm depth leaves room for rear-access wiring in a 200 mm deep enclosure.