What this MCB is and what the ratings mean for fit
The ABB S803S-D80 is a 3-pole miniature circuit breaker from the S800S series, rated 80 A with a Trip Curve D characteristic. That D-curve means it tolerates the high inrush currents typical of motor loads, transformers, and welding equipment — the magnetic trip threshold sits at 10 to 20 times rated current, so you won't get nuisance tripping when a pump or compressor starts. The 50 kA interrupting capacity at 230 VAC tells you it can safely clear a bolted fault up to that level without welding its contacts or cascading upstream — a figure that matters when you're coordinating selectivity in a panel feeding multiple motor starters. Mounting is standard DIN rail, so it drops into the same footprint as the older S200 or S500 series breakers you might be replacing. No need to gut the whole line — pull the old unit, clip this one on, and re-terminate. The 3-pole configuration covers three-phase circuits, which is the norm for motor branch circuits in industrial control panels.
Where it fits in the panel
This breaker lives on a DIN rail inside a distribution board or motor control center. The S800S series is ABB's high-performance MCB line, so you're getting a compact package that handles fault levels that would melt a standard domestic MCB. If you're retrofitting an older panel that had an S500 or S200 series breaker at this amp rating, check the busbar pitch — the S800S footprint is the same 3-module width per pole, so the mechanical fit is usually a straight swap.