The S802S-B40 is a 2-pole 40 A miniature circuit breaker with Trip Curve B characteristic, rated for 230 VAC and a 50 kA interrupting capacity. That 50 kA interrupting rating at 230 V means it can safely clear a bolted fault up to 50,000 amps without welding its contacts or rupturing the case — critical for high-fault-capacity panels where standard 10 kA breakers would fail.
The 2-pole form factor takes two module widths (36 mm typical). Wire termination is tunnel-type screw terminals; torque to the value stamped on the side — overtightening cracks the housing on these high-rupturing-capacity breakers.