The ABB S202-D3 is a 2-pole miniature circuit breaker with a Trip Curve D characteristic, rated 3 A at 277 V AC. The Trip Curve D means the magnetic trip threshold is 10 to 20 times the rated current (30–60 A), designed for loads with high inrush like small motors, transformers, or solenoid banks. On a 277 V line-to-neutral system (common in North American commercial lighting panels), the 6 kA interrupting rating tells you it can safely clear a fault up to 6,000 A without welding its contacts or venting arc gas into the enclosure. That's adequate for most downstream panelboards with available fault current under that number — but verify your point-of-supply SCCR before committing the BOM line.
Panel integration
The 2-pole width (two modular units, 36 mm) fits existing distribution boards without re-drilling. Wire terminals accept up to 25 mm² conductor; torque to 2.5 Nm per the marking on the terminal clamp. No special busbar or adapter needed for a standard 2-pole comb bus.