The Siemens 3VA1220-5EE42-0AA0-ZD00 is a 4-pole IEC frame 250 molded case circuit breaker with a 55 kA interrupting capacity at 415 V AC — breaking capacity class M. The thermal-magnetic trip unit (TM220, ATFM) is set for line protection with a fixed In of 200 A; the overload Ir is adjustable from 140 A to 200 A, and the short-circuit pickup Ii is fixed at 10 x In (2000 A). The N conductor is unprotected — the breaker trips on the three phases only, so the neutral is switched but not monitored for overcurrent.
Deployment and panel integration
The 4-pole form factor (3 protected phases + switched neutral) suits three-phase four-wire systems where the neutral bus must be disconnected for isolation but does not need its own overcurrent protection. The nut keeper kit simplifies torque-down on the line and load terminals — one less loose washer to drop into a live panel.