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    Grounded conductor required?

    A detached building being fed from another building only needs a 480 volt 3 phase delta feed. Are we required to pull the grounded conductor and land it even though it will not be used?
    Code reference please.
    Sometimes I don't know whether I'm the boxer or the bag.

    #2
    Does it already have service from another feed?

    Comment


      #3
      nope - For grounded systems, only have to bring the grounded conductor to the service equipment. 250.24.C

      If there are no 277 loads, you don't need it. And it won't make the installation any safer.
      Last edited by iceworm; 11-01-18, 03:07 PM. Reason: fat fingered the send button
      Without data you’re just another person with an opinion – Edwards Deming

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        #4
        I agree- not needed however, it is hard to believe that lighting would not be needed there. I would pull a grounded conductor at least the size of the equipment grounding conductor.

        I guess it is possible there will be a separate 240/120 v line also.
        They say I shot a man named Gray and took his wife to Italy
        She inherited a million bucks and when she died it came to me
        I can't help it if I'm lucky

        Comment


          #5
          Originally posted by Dennis Alwon View Post
          I guess it is possible there will be a separate 240/120 v line also.
          So you can feed a detached structure with (2) separate feeds?

          I didn't think that was allowed.

          JAP>

          Comment


            #6
            Originally posted by jap View Post
            So you can feed a detached structure with (2) separate feeds? I didn't think that was allowed.
            225.30 allows it under limited circumstances. One 480V feeder and one 120/240V feeder is among the allowed circumstances.
            Charles E. Beck, P.E., Seattle
            Comments based on 2017 NEC unless otherwise noted.

            Comment


              #7
              Isn’t the restriction over feeds concerned with services of same voltage? Thus a 277 service would not truly work the same as a 120/240 service and would have its own main disconnect etc...
              or am I wrong? Because I have seen many businesses served by multiple feeds of differing voltages, and secondary buildings fed from these same services.
              Student of electrical codes. Please Take others advice first.

              Comment


                #8
                Originally posted by Adamjamma View Post
                Isn’t the restriction over feeds concerned with services of same voltage?
                Take a look at 225.30(D).

                Charles E. Beck, P.E., Seattle
                Comments based on 2017 NEC unless otherwise noted.

                Comment


                  #9
                  Originally posted by Dennis Alwon View Post
                  I guess it is possible there will be a separate 240/120 v line also.
                  Or perhaps a step-down, single phase 480 - 120/240V transformer.
                  Charles E. Beck, P.E., Seattle
                  Comments based on 2017 NEC unless otherwise noted.

                  Comment


                    #10
                    Originally posted by charlie b View Post
                    Take a look at 225.30(D).

                    Right.. what I thought.. additional feeders or branch circuits shall be permitted... for different voltages, frequencies, or phases, or for different uses..


                    which to me means that if the person is using 277 three phase and later adds a second service feed of 120/240 single phase it is allowed... does not violate anything... under the different characteristics provisions...

                    same as if exceeds a certain amperage at 1 thousand volts..lol...
                    Student of electrical codes. Please Take others advice first.

                    Comment


                      #11
                      Originally posted by Adamjamma View Post
                      277 three phase





                      JAP>

                      Comment


                        #12
                        Application is Industrial, Process

                        Most I see are HRG, 480V systems. So single phase 277V is not available.

                        Feeders to buildings will be 3ph, 480V, no neutral, healthy EGC - generally feeding an MCC, or 480 panelboard. Lighting loads are dealt with, similar to Charlie's post, except using a 75kva, 3ph, 480D/208Y solid grounded, xfm feeding a 225A, 208/120, panel.

                        277V single phase loads are usually heat trace. Installation will be a 75KVA, 480D/480Y solid grounded, transformer, feeding a 100A panelboard.
                        Without data you’re just another person with an opinion – Edwards Deming

                        Comment


                          #13
                          Originally posted by jap View Post



                          JAP>
                          ok.. never used it or dealt with it but.. it is a different voltage from 120/240 so it is covered under the separate characteristics exemption.. even if it is still a single phase service...
                          Student of electrical codes. Please Take others advice first.

                          Comment


                            #14
                            Originally posted by Dennis Alwon View Post
                            I agree- not needed however, it is hard to believe that lighting would not be needed there. I would pull a grounded conductor at least the size of the equipment grounding conductor.

                            I guess it is possible there will be a separate 240/120 v line also.
                            Yep. Its always a good idea to pull a grounded conductor initially rather than later, at a higher cost.

                            Comment


                              #15
                              Originally posted by charlie b View Post

                              Or perhaps a step-down, single phase 480 - 120/240V transformer.
                              This is correct, there will be (2) 480-120/208 xfmr's in the building.
                              I knew if it was a service it had to have a grounded conductor bought to it and connected. but I wasn't sure about a feeder ran to a detached building.
                              Sometimes I don't know whether I'm the boxer or the bag.

                              Comment

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