The S801S-B20 is a 1-pole miniature circuit breaker rated 20 A with a Trip Curve B characteristic, meaning it trips instantaneously at 3 to 5 times rated current — suited for protecting resistive or lightly inductive loads where inrush is low, like lighting circuits or control transformers. Its 50 kA interrupting capacity at 400/690 VAC gives it headroom for high-fault installations without cascading upstream breakers. The DIN rail mount snaps into standard 35 mm rail in a distribution board or control panel.
Single-pole format occupies one module width on the DIN rail. The thermal-magnetic trip mechanism provides overload protection without external relays. Rated operational voltage spans 400/690 VAC and 125 VDC, so it covers both AC distribution and DC control circuits in mixed-voltage panels.