What this MCCB is and what it does
The Siemens SENTRON 3VA1120-4EF36-0DA0 is a 3-pole molded case circuit breaker (MCCB) rated for line protection — the job of protecting cables and busbars from overloads and short circuits in a distribution panel. Its TM240 thermal-magnetic release gives it a fixed thermal pickup at 20 A continuous current, with magnetic trip set at 240 A (10x In). That thermal rating holds flat at 20 A from 40 °C up to 50 °C, then derates to 18 A at 70 °C — so in a warm enclosure you lose about 10% of headroom, which matters when sizing for a fully loaded cabinet. Breaking capacity is the headline here: 121 kA at 240 V, 75.6 kA at 415 V, 52.5 kA at 440 V, and 11.9 kA at 690 V. That 75.6 kA at 415 V puts it comfortably above typical 50 kA or 65 kA SCCR requirements for most industrial panel feeds — you get selectivity headroom without stepping up to a larger frame. The 800 V rated insulation voltage (Ui) confirms it's rated for 690 V line-to-line systems.
Panel fit and integration
The 3VA1120-4EF36-0DA0 measures 76.2 mm wide, 130 mm tall, and 70 mm deep — a standard 3-pole MCCB footprint that drops into a SENTRON panelboard or a separate enclosure without re-drilling the mounting plate. Front protection is IP40, so it's fine for a clean indoor panel but not for washdown areas. The undervoltage release (UVR) is built in (design code 3VA9608-0BB25), which means the breaker trips if control voltage drops — common for emergency-stop chains or power-loss protection on motor feeds. No auxiliary contacts or ground-fault module are included; those would need the separate accessory slot.