What this 3VA1 breaker is and what it does
The Siemens 3VA1110-5GF42-0AA0-ZD00 is a 4-pole IEC molded case circuit breaker from the 3VA1 frame-160 series, rated 100 A continuous with a breaking capacity of 55 kA at 415 V (class M). That Icu figure means it can safely clear a bolted fault up to 55 kA without welding its contacts or rupturing the arc chamber — a critical number for panel SCCR coordination when the upstream transformer can deliver that kind of fault current. The thermal-magnetic trip unit is a TM240 with adjustable overload protection (Ir) from 70 A to 100 A and fixed short-circuit pickup (Ii) at 5 to 10 times In. That 5–10× band is typical for line protection on motor feeders or distribution subfeeds where you need some inrush headroom but still want fast clearing on hard faults. It includes 100% N-conductor protection — the neutral pole is switched and protected at the same rating as the phase poles — and ships with a nut keeper kit for DC Power OEM applications in China. The nut keeper is a small detail but saves panel-build time on the assembly line.