The Siemens 3VA1225-4GF42-0AA0-ZD00 is a 4-pole IEC frame 250 molded case circuit breaker from the 3VA1 series, rated for line protection with a TM240 thermal-magnetic trip unit. Its headline breaking capacity is 36 kA at 415 V (class S), meaning it can safely interrupt fault currents up to that level without upstream cascading — a key spec for panel builders sizing the main breaker in a distribution board. The thermal overload pickup Ir is adjustable from 175 A to 250 A, and the magnetic short-circuit pickup Ii is fixed at 5 to 10 times In, so the breaker covers motor-start inrush or transformer magnetizing peaks without nuisance tripping.
What the Ratings Mean for Fit
The 36 kA Icu at 415 V is the ultimate short-circuit breaking capacity — the breaker can interrupt one fault at that level and still be serviceable. For a panel on a 400 V industrial supply with a transformer rating above 1 MVA, that SCCR typically clears the fault without needing a current-limiting upstream fuse. The adjustable Ir (175–250 A) lets the thermal trip match the actual load current, so an MRO planner can dial it to the exact cable or bus rating on site. The magnetic Ii range of 5–10 x In (1250–2500 A) handles motor starting currents up to about 8x FLA for a 250 A motor circuit, which covers most IEC frame 250 applications.
Deployment Context
The 4-pole configuration with 100% N conductor protection means the neutral pole is fully rated and switched — required for TN-S or TT systems where the neutral is not solidly bonded. The nut keeper kit suggests this variant is destined for a DC Power OEM in China, likely for a solar or battery energy storage system where the breaker mounts in a pre-drilled panel or enclosure. The 3VA1 frame is designed for DIN-rail or screw-mount integration in standard distribution boards.