Panel fit and protection profile
The ABB S203-C63 is a 3-pole miniature circuit breaker rated 63 A with a C-trip curve, designed for DIN-rail mounting in distribution boards and sub-panels. The C-curve trips between 5 and 10 times rated current, so it handles moderate inrush from motor starters and small transformers without nuisance opening while still clearing short circuits quickly. The 6 kA interrupting rating at 277 VAC per pole means it can safely break fault currents up to that level — adequate for most commercial and light industrial panelboards where the prospective fault current stays under that threshold.