Single Phase Distribution Lines

Most residential customers only require single phase service (rather than three phase service). It is less costly to build single phase lines in areas that are strictly residential. Instead of running single phase lines from the distribution substation, it is more common to "tap" single phase lines off a three phase line. These single phase lines are sometimes called single phase feeders.

Single Phase Feeder PictureA single phase feeder starts with a primary tap off one of the phases of the three phase distribution line through a line fuse or a fused cutout. The second wire required to complete the single phase feeder circuit is tapped with a direct connection to the distribution circuit neutral wire. The single phase feeder may be strung overhead through a residential neighborhood, or it may be an underground circuit. If it is buried, the tap point and the fuse cutout will usually be protected by a lightning arrester. It will protect the underground line from lightning surges which may hit the main overhead primary line. If the single phase feeder is overhead, lightning arresters will usually be installed at each transformer location.