What it is and what the ratings mean for fit
The Siemens 3VA2110-5HN32-0AA0 is a SENTRON 3VA2 molded case circuit breaker (MCCB) designed for line protection — meaning it sits on the incoming feeder, not a motor branch. It carries a 100 A rated continuous current at 40 °C and holds that same 100 A rating all the way up to 70 °C, so no derating needed in a warm panel. The 1200 A frame means the breaker body is sized for that interrupting capacity, not the continuous rating — you get a physically large frame for a 100 A load, which gives you headroom on the interrupting side. Interrupting capacity is the headline here: 187 kA at 240 V, 121 kA at 415 V and 440 V, 75.6 kA at 500 V, and 3.7 kA at 690 V. That 187 kA at 240 V is a high-interrupting rating — it can clear a massive fault without rupturing, which matters on a transformer secondary or a high-capacity bus. The sharp drop at 690 V (3.7 kA) is typical for a 3-pole MCCB on a line-to-line 690 V system; the arc extinction physics limit it. The electronic trip unit is an ETU350 — that's a basic thermal-magnetic replacement with adjustable long-time and short-time pickup, plus instantaneous. No ground-fault monitoring on this variant, no communication module, no undervoltage release. It's a plain line-protection breaker: set the dials, wire it in, and it clears faults.
Panel fit and mounting
The 3VA2110-5HN32-0AA0 measures 105 mm wide, 181 mm tall, and 86 mm deep. That 105 mm width is a standard 3-pole MCCB footprint for the SENTRON 3VA2 family — it occupies three 35 mm DIN spaces (3 x 35 mm = 105 mm). The 86 mm depth means it projects less than 90 mm from the DIN rail, leaving room for wiring gutters or a shallow enclosure. IP40 on the front means it's protected against tools and wires >1 mm, but not against water — keep it inside a panel, not in a washdown zone.