Bus coupler is a device which is used to couple one bus to the other without any interruption in power supply and without creating hazardous arcs. Bus coupler is a breaker used to couple two busbars in order to perform maintenance on other circuit breakers associated with that busbar.
Where is bus bar used?
Rather than branching the main supply at one location, busbars allow new circuits to branch off anywhere along the route of the busway. A busbar is used to connect high voltage equipment at electrical switchyards, and low voltage equipment in battery banks but also prominent in the automotive and defence sectors.
Why bus riser is used?
Bus riser is a set of bus bar that connected from the coupler breakers, outgoing section enclose in the panel and connected to your incoming 1 or incoming 2 bus bar section. It depend which side is your outgoing from the bus bar coupler breakers or depend on your electrical design.