480 volt single phase lighting

Discussion in 'General Electronics Chat' started by Talmadge, Mar 30, 2007.

  1. Talmadge

    Talmadge Thread Starter New Member

    Mar 30, 2007

    I am new to this forum, I hope that I am posting my question in the right spot.

    Help! please, I have a situation where all of the lighting in our new (not newly constructed) facillity does not work in our parking lot and I have never encountered the type of lighting fixture on our poles.

    I am the maintenance electrician, Our service is 480 3 phase, 277 phase to ground and 480 pahse to phase. the transformers (ballasts) in this particuler light fixture has a common, a 120 volt lead, a 208 volt lead, a 240 volt lead, a 277 volt lead and a 480 volt lead. I have three phases and a neutral available in each light standard (pole). The curent configuration is the common is connected to the neutral as it should be and the 480 volt lead is connected to one leg (phase) of 480 which would be 277 volts. All of the parking ot lighting was installed in 1988 the fixtures are very old and we are going to rebuild them. but I need to know what type of balasts should I order. I have never heard of 480 single phase, that is what these light were hooked up as originally. I guess my question is could someone explain 480 single phase to me and how is it different from 277?

    Any help would be apreciated.
  2. Sparkyfrm

    Sparkyfrm New Member

    Apr 1, 2007
    Single phase 480 is 277 volt. To get 480 you need two phase at any given time to give you 480 volts. In (3) three phase systems, they alt. between the (3) different phase . That why with a motor, if you switch two of the phase make up points then the motor will change direction of rotation.
    You will need a 277 volt ballast for the type of lighting you are using; being it be Metal halide lamp, high-pressure Mercury Lamp,or high-pressure sodium .
    You might just have bad cap. or ign. not the ballist it self.
  3. cavie

    cavie New Member

    Dec 20, 2008
    480 volt single wire 2 is used in highway lighting. It is 480 volts to ground. Had a hard time getting my head wraped around it.