What the ratings mean for fit
The Siemens 3VA1120-5EF36-0DH0 is a 3-pole IEC moulded-case circuit breaker on the 3VA1 platform, built into the 160 A frame. Its headline rating is a 55 kA breaking capacity at 415 V AC (class M), which means it can safely interrupt a fault current up to that level without rupturing — critical for high-fault panels where upstream coordination demands a high interrupting rating. The thermal-magnetic trip unit (TM240, ATAM) provides adjustable overload protection (Ir = 14…20 A) and fixed short-circuit pickup (Ii = 8…16 × In, so 160…320 A at the 20 A rating). That adjustability lets the panel builder fine-tune the overload band to the connected load without swapping the breaker body. The integrated undervoltage release (UVR, 208–230 V AC 50/60 Hz) drops the breaker open when control voltage falls below its dropout threshold — a standard requirement in safety circuits that need a fail-safe disconnect on loss of control power. Two auxiliary switches (HQ type) and one trip-alarm switch report the breaker status back to a PLC or annunciator panel.