This is a typical installation of low voltage pool/spa lighting with the tan colored transformers located on the left hand side. The transformers reduce the voltage from 125 volts to 12-16 volts. The transformers come with a setting switch to set the voltage anywhere between 12-16 volts. The reason that voltage varies is because the farther away the transformer is from the low voltage pool/spa light, the higher the the voltage needs to be for voltage drop due to the length of light cable. The junction cans on the right hand side hold conduits that go to all the pool/spa lights. In this case there are 8 lights. Low voltage lighting has become far more popular than standard 125 volt lighting from the past. The lights are substantially smaller and look nicer in the pool/spa. Some even have automatic color changing ability.
