What it is and what it does
The Siemens 3VA1110-4GF42-0AA0 is a SENTRON molded case circuit breaker (MCCB) with four poles, rated for line protection. It carries 100 A continuously at 40 °C ambient — no derating needed until you cross 55 °C, where it steps down to 98 A, then 96 A at 60 °C, 94 A at 65 °C, and 91 A at 70 °C. That thermal curve means you can push it in a warm panel without losing headroom, as long as you stay under 55 °C for full current. Breaking capacity is 121 kA at 240 V AC, 75.6 kA at 415 V, 52.5 kA at 440 V, and 11.9 kA at both 500 V and 690 V. Those numbers cover most industrial service-entrance and distribution applications where high fault current is a concern. The overcurrent release is a TM240 thermal-magnetic type — fixed thermal and magnetic trip, no electronic adjustment, which keeps it simple and reliable for standard feeder protection.
Panel fit and integration
It measures 130 mm high, 101.6 mm wide, and 70 mm deep — a 4-pole MCCB that fits standard distribution panel footprints. Front protection is IP40, meaning it's sealed against tools and wires over 1 mm but not against water ingress; keep it inside a rated enclosure. The N-conductor protection is rated at 100% of the phase current, which matters for panels feeding nonlinear loads where the neutral carries harmonics. Rated insulation voltage is 800 V, and the maximum operating voltage is 690 V AC, so it's comfortable in 400 V and 480 V systems with margin. Power loss maxes out at 25 W — negligible for panel thermal budgeting, but worth noting if you're packing multiple breakers in a sealed enclosure.