The Siemens 3VA1125-5GE42-0AA0-ZD00 is a 4-pole IEC frame 160 molded case circuit breaker with a 25 A rating and a breaking capacity class M — meaning it interrupts 55 kA at 415 V without venting or damage to the bus. That Icu figure governs fault-energy handling in a panel; if your SCCR study calls for 55 kA at that voltage, this breaker holds the line without cascading upstream. It ships with a TM220 thermal-magnetic trip unit, adjustable overload protection from 18 A to 25 A, and a fixed short-circuit pickup of 12.8 x In. The 100% N-conductor protection and the included nut keeper kit suggest this variant was configured for a DC Power OEM build in China — so the neutral pole is fully rated, not just switched.
What the Ratings Mean for Fit
The 55 kA Icu at 415 V is the maximum short-circuit current the breaker can safely interrupt once — it's not a continuous rating. If your transformer or generator can deliver a fault current above that number, you need a higher-breaking-capacity frame or a current-limiting upstream device. The adjustable Ir (18-25 A) lets you dial in the overload protection to match the cable or load without swapping the trip unit. The 4-pole configuration with 100% N protection means the neutral pole is protected against overload and short-circuit, not just switched. That's required for systems where the neutral carries unbalanced load current — common in 3-phase 4-wire distribution panels.