The ABB S803S-B40 is a 40 A, 3-pole miniature circuit breaker (MCB) with a Trip Curve B characteristic. The 50 kA interrupting rating at 400 V AC means it can safely clear a bolted fault up to that level without welding its contacts or rupturing the case — critical for high-fault-capacity panels where a standard 10 kA MCB would fail. Curve B trips between 3× and 5× rated current (120–200 A), so it's sized for resistive or lightly inductive loads where inrush is low; it will nuisance-trip on motor or transformer starts that draw higher peaks.
This is a current-production part.
Panel integration
Rated 400/690 V AC, 375 V DC, 50/60 Hz — suitable for three-phase distribution panels in commercial or light industrial switchgear.