The S803N-B20: Rated for 20 A per pole with a B-trip characteristic, this MCB protects against overload and short-circuit in final circuits where the load is predominantly resistive or low-inrush — think lighting, small heaters, or control transformers. The B-curve trips between 3 and 5 times rated current, so it clears fast on a hard fault but won't nuisance-trip on the mild inrush of a contactor coil or a bank of LEDs.
Snaps onto standard DIN rail in the distribution board. The S800N platform uses a modular 18 mm per pole footprint, so this 3-pole unit occupies three modules (54 mm). Terminals accept up to 35 mm² conductor — sized for the feeder cable a 20 A circuit typically calls for.