The Siemens 3VA1120-3GE42-0AA0-ZD00 is a 4-pole circuit breaker from the 3VA1 IEC frame 160 series, rated at 20 A with a breaking capacity of 25 kA at 415 V (class N). It carries TM220 line protection with an ATFM trip unit — overload protection adjustable from 14 A to 20 A, and short-circuit protection set at 16 x In. The N conductor is protected at 100%, and the unit includes a nut keeper kit, specified for DC Power OEM applications in China.
What the ratings mean for fit
The 25 kA Icu at 415 V defines the maximum fault current this breaker can safely interrupt without damage — critical for verifying SCCR compliance in a panel. The adjustable overload Ir (14–20 A) lets you dial in the exact motor or feeder FLA without swapping the breaker body. The 16 x In instantaneous trip (Ii) means it clears hard shorts fast, but won't nuisance-trip on moderate inrush from a transformer or motor start. The 100% N protection is non-standard for IEC breakers — it keeps the neutral fully rated, which matters for harmonic-rich loads or single-phase fault return paths.