Siemens 3VA1112-3EE42-0AA0-ZD00 — IEC Frame 160 Circuit Breaker, 125 A, 25 kA @ 415 V
The Siemens 3VA1112-3EE42-0AA0-ZD00 is a 4-pole IEC frame 160 circuit breaker rated for line protection, with a breaking capacity class N delivering 25 kA Icu at 415 V. Its thermal-magnetic trip unit (TM220, ATFM) sets overload protection adjustable from 88 A to 125 A, and short-circuit protection fixed at 10 × In. The N conductor is unprotected — standard for a 3-pole + N configuration where the neutral is not switched.
What the Ratings Mean for Your Panel
The 25 kA Icu at 415 V means this breaker can safely interrupt fault currents up to that level without welding its contacts or rupturing the arc chamber — essential for downstream selectivity in a distribution board fed by a transformer of that capacity. The 125 A In and adjustable Ir (88–125 A) let you match the thermal trip to the actual continuous load, not just the breaker frame size. The fixed Ii = 10 × In (1,250 A magnetic pickup) is suited for motor or transformer branch circuits where inrush must ride through without nuisance tripping. This breaker mounts on a standard DIN rail or panel-mount plate inside a switchboard or enclosure. The 4-pole form factor (3 protected poles + unprotected neutral) is typical for three-phase, four-wire systems where the neutral is bonded to ground at the service entrance and does not require overcurrent protection.
Integration Note for the OEM or Panel Builder
The nut keeper kit for DC Power OEM in China is a factory-fitted option that secures the line-side and load-side lugs against loosening under vibration — relevant if this breaker ships as part of a DC power supply assembly. The TM220 trip unit is thermal-magnetic; no electronic adjustment or communication module is included. For selectivity coordination, pair this with an upstream 3VA1 or 3VA2 frame sized one step larger (frame 250 or 400) at the same 25 kA rating.