The Siemens 3VA1150-4GE42-0AA0-ZD00 is a 4-pole IEC frame 160 molded case circuit breaker with a 50 A thermal-magnetic trip unit (TM220).
Trip settings and protection
Overload protection (Ir) is adjustable from 35 A to 50 A via the TM220 dial — set it to match the continuous load current, not the breaker's In. Short-circuit pickup (Ii) is fixed at 10 x In, so 500 A instantaneous. That's a standard motor-starting curve; it rides through inrush on a 30–40 A motor but trips fast on a hard phase-to-phase fault. The N-conductor protection is set to 100 %, meaning the neutral pole tracks the phase poles — common for 4-wire systems where the neutral carries harmonic or unbalanced current.
The nut keeper kit (part of the D00 variant) retains the terminal nuts during wiring — saves time on a production line or panel shop. Four-pole means it occupies the full width of a 160 A frame; check the enclosure fill factor if you're retrofitting into an existing MCC bucket.