The ABB 1SAM401920R1002 is a circuit breaker busbar, classified under Circuit Breaker Accessories and specifically Circuit Breaker Busbars. It's the copper or aluminum distribution bar that links multiple breaker poles together in a panel, feeding the line side from a single incoming feed rather than daisy-chaining individual wires.
What the category tells you
Falling under Circuit Breaker Accessories and Busbars, this part is a mechanical and electrical interface, not a standalone protective device. It doesn't carry a current rating or breaking capacity of its own — those are properties of the breaker it connects to. The busbar's job is to maintain low impedance across the breaker line-up and handle the full rated current of the panel's main feed without exceeding a 30 °C temperature rise at the connection points. Mounts directly onto the breaker terminals; no DIN-rail adapter needed.