The Siemens 3VA1125-3EF32-0AA0-ZD00 is a 3-pole IEC frame 160 molded case circuit breaker with a 25 kA interrupting capacity at 415 V (breaking capacity class N). It's configured for line protection with a TM240 thermal-magnetic trip unit, rated In=25 A, with adjustable overload protection Ir from 18 A to 25 A and short-circuit protection Ii adjustable from 6.4 to 12.8 times In. The suffix ZD00 adds a nut keeper kit, and this variant is built for a DC Power OEM in China.
The TM240 trip unit gives you a thermal curve for overloads and a magnetic instantaneous pickup for shorts. The adjustable Ir (18–25 A) lets you fine-tune the continuous current rating to match the downstream load, while the Ii range (6.4–12.8 x In, so 160–320 A at the 25 A setting) sets the magnetic trip threshold. That's a wide adjustment band, useful for coordinating with motor inrush or transformer energization without nuisance tripping.
Deployment context
The nut keeper kit (ZD00 suffix) prevents hardware loosening under vibration, which is a common requirement for DC Power OEM equipment shipped to China.