What the ratings mean for fit
The ABB S201-B16NA is a 1-pole+N miniature circuit breaker with a 16 A rated current and a Trip Curve B characteristic. That B curve means it trips between 3 and 5 times rated current on a magnetic short-circuit — designed for resistive and lighting loads where inrush isn't heavy. The 277 VAC rating covers most single-phase North American panel voltages, and the 6 kA interrupting rating is enough for residential and light commercial service entrance panels where the available fault current stays under that threshold. It snaps onto standard DIN rail, so it drops into any existing S200-series distribution board without adapters.
Panel integration notes
Mounts on standard 35 mm DIN rail. The 1-pole+N format takes up one module width — leaves room for adjacent breakers in the same distribution board. Terminal capacity accepts up to 25 mm² conductor; strip length 10 mm. No special tooling needed for installation.