What this part is and what it isn't
The Siemens 3VA1110-1AA42-0AD0 is a SENTRON switch disconnector in a molded-case circuit breaker (MCCB) form factor — IEC frame 160, 4-pole, rated 100 A continuously across the full 40 °C to 70 °C ambient range. That flat thermal curve means no derating as the panel warms up; it holds 100 A at 70 °C just as it does at 40 °C. What it doesn't do: no overload protection, no short-circuit protection, no undervoltage release, no voltage trip, no communication function. It's a pure disconnect — a service-rated switch in an MCCB footprint, meant for isolation where the upstream device handles the fault interruption.
Where it fits in the panel
Front-terminal busbar connection — this is the main circuit entry, not a box-terminal lug. That means it's designed for a busbar stack or plug-in feeder, not for landing field cables directly. The 101.6 mm width (4-pole) and 70 mm depth keep it within the standard SENTRON 3VA panel footprint; it shares the same 130 mm height as the rest of the 160-frame family. Three HQ auxiliary switches (changeover contacts) ride on the side, giving you status feedback without an add-on module. The IP40 front face is fine for a closed panel; no washdown rating here.
Key ratings at a glance
Rated insulation voltage 800 V, operating voltage 690 V AC / 600 V DC. Max power loss 38 W — that's the heat it dumps into the enclosure at full rated current. Mechanical service life 15,000 operating cycles typical. Storage range -40 °C to 80 °C; operating range -25 °C to 70 °C. The 100 A rating is flat across the entire operating temperature band — no derating curve to calculate.