The Siemens 3VA1125-4GF42-0AA0-ZD00 is a 4-pole IEC frame 160 circuit breaker in breaking capacity class S, rated Icu=36kA at 415V. It carries a TM240 thermal-magnetic trip unit with ATAM (adjustable thermal, adjustable magnetic) — overload protection Ir adjustable from 18A to 25A, short-circuit protection Ii adjustable from 6.4 to 12.8 times In. The N conductor is protected at 100%.
The TM240 trip unit gives you field-adjustable overload (Ir) and short-circuit (Ii) settings, so you tune the protection to the actual load cable and motor inrush without swapping the breaker. The 100% N protection means the neutral pole is fully rated and trips with the phases, not derated or omitted — required for systems with significant harmonic or unbalanced loads.
Deployment context
The 4-pole format suits three-phase four-wire systems (e.g. TN-S or TN-C-S) where neutral protection is mandatory. The nut keeper kit included suggests an OEM application in China where DC power distribution is common — verify the DC rating if using on a DC bus.