What it is and what it does
The Siemens 3RT1926-4CC20 is a 3-phase busbar designed to bridge the line-side power terminals of two Size S0 power contactors mounted side-by-side at 45 mm modular spacing. It eliminates individual wiring between the contactors, reducing panel assembly time and potential for loose connections in the main power path.
Integration note for panel builders
This busbar snaps onto the contactor power terminals without tools. The 45 mm spacing matches the standard DIN-rail pitch for S0 contactors, so the contactors mount directly on the rail and the busbar bridges them without additional adapters. Verify the contactor terminal layout matches the busbar's footprint before assembly.