The Siemens 3VA1220-4GF42-0AA0-ZD00 is a 4-pole IEC molded case circuit breaker from the 3VA1 frame-250 series, rated for line protection with a TM240 ATAM thermal-magnetic trip unit. Its interrupting capacity hits 36 kA at 415 V (breaking capacity class S), sized for industrial distribution panels where fault current levels demand a high-break device rather than a standard 25 kA class.
Trip settings and coordination
Overload protection (Ir) adjusts from 140 A to 200 A via the TM240 thermal element, matching a 200 A frame (In). Short-circuit magnetic pickup (Ii) is fixed at 5 to 10 times In, so on a 200 A setting the instantaneous trip fires between 1000 A and 2000 A. That range gives selectivity headroom downstream — a 200 A feeder can coordinate with 100 A branch breakers without nuisance tripping on motor inrush. The N-conductor protection is set to 100%, meaning the neutral pole is fully rated and protected at the same level as the phase poles — important for 4-wire systems with harmonic currents or non-linear loads where neutral current can approach phase current.