The Siemens 3VA1125-6EE42-0AA0-ZD00 is a 4-pole IEC frame 160 molded case circuit breaker (MCCB) with a 25 A thermal-magnetic trip unit (TM220, ATFM). The headline figure here is the 70 kA breaking capacity at 415 V (class H) — that means it can safely interrupt a fault current up to 70,000 A without welding contacts or venting gas into the panel. That rating is what determines whether this breaker holds its downstream coordination in a high-fault installation like a transformer secondary or a large motor control center.
Overload and short-circuit settings
Overload protection (Ir) is adjustable from 18 A to 25 A via the thermal dial, so you set it to the actual continuous load current, not the breaker's In. Short-circuit pickup (Ii) is fixed at 12.8 x In — that's 320 A at the 25 A setting. That's a magnetic-only instantaneous trip; it clears hard faults fast but won't nuisance-trip on motor inrush if the motor FLA is well below the pickup. The neutral conductor is unprotected on this variant (N conductor unprotected), so confirm your system grounding scheme before wiring.