What this 3VA1 frame breaker delivers
The Siemens 3VA1120-3EF42-0AA0-ZD00 is a 4-pole IEC frame 160 molded case circuit breaker in the 3VA1 series, rated for line protection with a TM240 thermal-magnetic trip unit. Its 20 A rated current (In) and adjustable overload protection from 14 A to 20 A (Ir) let you dial in the exact continuous-current limit for the downstream load — useful when the branch circuit draws less than the full 20 A and you want tighter coordination. The short-circuit pickup (Ii) is adjustable from 8 to 16 times In, so magnetic tripping can be set between 160 A and 320 A to ride through motor inrush or transformer energization without nuisance trips.
The suffix "-ZD00" indicates a special OEM configuration (nut keeper kit, DC Power OEM in China). If your application does not require that specific accessory kit, the base order code 3VA1120-3EF42-0AA0 may be a simpler alternative — verify with your Siemens representative whether the nut keeper kit is needed for your panel assembly.
Deployment context
The 4-pole footprint with unprotected neutral means the neutral busbar passes through without interruption — plan your phase-to-neutral fault path accordingly (the breaker clears phase faults only; neutral-ground faults rely on upstream protection).