The circuits in a switchyard are connected to common conductors called what?

• A. Phases
• B. Buses
• C. Lines
• D. Grounds

Answer: (B)

The common conductor in a switchyard is the bus (busbar) system. A bus is a thick, solid conductor or set of conductors that acts as a central distribution point, where multiple circuits connect via breakers or switches. Power from sources or transformers rides onto the bus and is then fed out to various feeders, keeping all attached circuits tied to the same voltage reference. This arrangement makes it easy to isolate sections for maintenance and to protect the system.

Phases are the individual current-carrying lines in a three-phase system and are not the shared conductor for all circuits. Lines refer to the actual outgoing conductors between equipment, which connect to the bus but are not the common distribution path themselves. Grounds are safety earth connections used for fault protection, not the normal power distribution path.