What the ratings mean for the BOM line
The 3VA1150-5EE42-0AA0-ZD00 is a Siemens 3VA1 IEC frame 160 molded-case circuit breaker, 4-pole, with a 50 A thermal-magnetic trip (TM220, ATFM). The Icu of 55 kA at 415 V puts it in breaking capacity class M — that is the maximum short-circuit current it can safely interrupt once without damage, so it suits high-fault panels downstream of a transformer or large motor branch. Overload protection is adjustable Ir=35…50 A; short-circuit pickup is fixed at Ii=10 x In (500 A). The N conductor is unprotected (solid neutral), meaning this breaker switches and protects the three phases only — the neutral passes through unswitched. The nut keeper kit is a mechanical accessory for DC Power OEM builds in China, not a functional rating.
Deployment context
Mounts in a standard panel on a DIN rail or direct-mount plate. The 4-pole form factor with unprotected neutral is typical for three-phase distribution where the neutral is bonded to ground at the service entrance and does not require overcurrent protection — common in IEC switchgear for commercial and light industrial panels.