What the ratings mean for fit
The 3VA1112-4EF36-0AB0 is a 3-pole IEC frame 160 molded-case circuit breaker with a 125 A continuous current rating and a 36 kA interrupting capacity at 415 V AC — breaking capacity class S. That 36 kA symmetrical rating at 415 V means it can safely clear a fault up to that level on a 400 V distribution bus without upstream fuses needing to intervene, which is the selectivity requirement for most industrial switchboards in petrochemical and process plants where fault current runs high. The thermal-magnetic TM240 trip unit gives adjustable overload protection from 88 A to 125 A via the Ir dial, and the short-circuit magnetic pickup Ii is adjustable from 5 to 10 times In (625 A to 1250 A). This lets you coordinate the breaker with downstream loads and upstream protective devices without swapping trip units. The ATAM designation confirms this is a fixed-thermal, adjustable-magnetic trip — standard for motor branch circuit and feeder protection where you need to set the instantaneous pickup above the motor inrush but still protect the cable. The two built-in auxiliary switches (HP) report open/closed status back to the PLC or DCS, which is useful for SIS loop monitoring in a safety-instrumented function where the breaker position must be confirmed on demand.
Where this breaker fits in the panel
The 3VA1 frame 160 mounts on a standard DIN rail or can be screw-fixed to a backplate in a low-voltage switchboard. The clamp connection accepts copper or aluminium conductors up to the frame's rated cross-section — no lug kit required for most feeder sizes. The two HP auxiliary switches plug into the breaker's accessory slot and share the same compact footprint, so the overall width stays at 3-pole spacing (about 105 mm). For a retrofit into an existing Siemens 3VA lineup, the mounting and busbar connection pattern is consistent across the frame.