Three-Phase and Single-Phase Electricity Distribution


So what does three phase and single phase electricity look like in the real world? The picture below shows a power pole. The power pole’s top crossbeam has three wires on it attached to three large green insulators. The three wires tell you straight away that this is delta-connected three phase. and the big insulators tells you that this is high voltage; this is a high-voltage distribution feeder.

The grey box is the transformer that reduces the voltage and changes the connection from delta to star. Three wires come from the feeder and connect to the top of the transformer.
The two crossbeams at the bottom carry four wires; these are the star-connected low-voltage distribution that comes from the transformer and distributes electricity to the greater general area.

The thick black cable is an aerial bundled cable, which is also star-connected low-voltage distribution. It distributes electricity to houses in the immediate area.

The thin black cable coming off the pole at an angle below the lowest crossbeams is a single-phase insulated lead-in to a single house right next to the power pole.

Next time you look at all of those wires and boxes up there you’ll know what they’re for and what they all mean. You should also know that if everyone had an Eniquest HPP in their yard we wouldn’t need these ugly poles and overhead wires!