What this breaker is and what the ratings mean
The Siemens 3VA1120-4EF32-0AA0-ZD00 is a 3-pole IEC frame 160 molded case circuit breaker with a 36 kA breaking capacity at 415 V (class S). That Icu rating means it can safely interrupt a fault current up to 36,000 A without welding contacts or damaging the enclosure — a key figure for panel SCCR compliance. The thermal-magnetic trip unit is a TM240 with an adjustable overload protection range of 14 A to 20 A (Ir) and a short-circuit protection pickup of 8 to 16 times In (Ii). For a 20 A fixed rating, that Ii range is 160 A to 320 A, which covers motor inrush and feeder coordination in standard industrial panels.
Where it fits in the panel
Mounts on a DIN rail in the distribution section of an industrial control panel. The 3-pole form factor handles three-phase loads — typical for branch protection on motor starters, conveyor drives, or lighting distribution. The adjustable thermal overload (Ir) lets you dial in the exact load current without swapping trip units, which simplifies spares stocking for a panel with mixed 16 A and 20 A circuits.