What it is and what it does
The ABB SH203T-C10 is a molded case circuit breaker (MCCB) from the SH203T series, part of ABB's System pro M compact line. It's a 3-pole breaker sized for protecting branch circuits in commercial and light industrial panels. The 'C10' designation means a 10 A rated current with a C-trip curve, so it handles moderate inrush from things like small motors or lighting ballasts without nuisance tripping, but still clears fast on a hard short.
