The ABB S803S-C16 is a 16 A, 3-pole miniature circuit breaker with Trip Curve C, meaning it's sized for general-purpose protection on motor and lighting circuits where moderate inrush (5–10× rated current) is expected — common for small pumps, fans, and distribution subfeeds in commercial and light industrial panels. The dual trip mechanism — thermal bimetal for overload, electromechanic solenoid for short-circuit — is standard for a thermal-magnetic MCB; the thermal element handles sustained overcurrents (time-delayed), while the magnetic element trips instantaneously on a hard fault.
Rated operational voltage is 400/690 VAC (line-to-line or line-to-neutral) and 375 VDC, so it works in both three-phase AC distribution and DC control circuits up to that voltage.