The D curve tolerates high inrush currents for motor or transformer branch circuits. Mounting is standard DIN rail, so it clips directly into a 35 mm rail inside a panel or enclosure. The 2-pole form factor occupies two module widths — plan your DIN rail fill accordingly. The 110 VDC rating covers control-circuit applications on DC buses, though the AC side at 277 VAC is the primary duty for most lighting or motor branch circuits.
How the S802UE-K20 compares to the S202M-B10
The closest functional peer is the S202M-B10. Both are 2-pole, DIN-rail MCBs with a 6 kA interrupting rating at 277 VAC. The critical difference is the trip curve: the S802UE-K20 uses Curve D, while the S202M-B10 uses Curve B.