Primary circuits are the distribution circuits that carry power from substations to local load areas. They are also called express feeders or distribution main feeders. The distribution feeder bay routes power from the substation to the distribution primary feeder circuits.
In the photo of the distribution main feeder the primary circuit is fed underground to a nearby distribution system overhead line. The yellow cables are the primary feeder lines going underground.
 Figure 1. 3phase distribution feeder bay |
 Figure 2. Distribution main feeder |
 Figure 3. Overhead primary feeder |
 Figure 4. Distribution primary feeder underbuild |
