The Siemens 3VA1120-5EF42-0AA0-ZD00 is a 4-pole circuit breaker from the 3VA1 IEC frame 160 series, rated for line protection with a TM240 thermal-magnetic trip unit. Breaking capacity sits at 55 kA at 415 V (class M), which means it can safely interrupt fault currents up to that level without upstream damage — a solid fit for panelboards and distribution boards where high fault current is a given.
Ratings and what they mean for fit
Rated In=20 A with overload protection adjustable from Ir=14 A to 20 A — that's the continuous current the breaker carries without tripping, and the adjustability lets you fine-tune it to the actual load without swapping the unit. Short-circuit protection is set at Ii=8 to 16 x In, so the magnetic trip responds between 160 A and 320 A depending on the dial setting. The N conductor is unprotected, meaning the neutral pole has no overcurrent protection — standard for TN systems where the neutral is bonded to ground and not expected to carry fault current.
Deployment context
The 3VA1 frame 160 mounts on a DIN rail inside a panel or enclosure — standard for IEC distribution boards. The nut keeper kit included in the suffix (ZD00) is a DC Power OEM variant, so this breaker ships with hardware for DC-side mounting in OEM equipment built in China. That's a detail to note if you're replacing a standard 3VA1: the ZD00 suffix changes the accessory kit, not the electrical ratings.