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  • new guy here. signed up to ask a question about neutral and ground.

    Of course I'm going to hang around and learn stuff besides just what I ask about today but I need to find out for sure on this matter.
    I've been dabbling in electricity for a good while and I can do the basic wiring you would do in a home. I've wired a couple of new homes but I've started a project that I'm not sure of. I'm wiring a barn. A metal barn.
    My load center has the neutral and ground common in the box and the box is bolted to the metal framing of the barn so of course, the framing and everything else is common with the neutral and ground.

    Here's my question...
    On my power outlets of course I know I need to run two wires, a hot and a neutral to them but is it necessary to also run a ground or can I just let the building be the ground?

    Thanks up front for all your answers.

    Allen

  • #2
    Re: new guy here. signed up to ask a question about neutral and ground.

    Hello Allen,Welcome to the forum.

    What are you going to wire it with?
    romex?
    mc cable?
    pvc?
    Metal conduit?

    Romex comes with a ground wire and so does mc cable.
    Pvc you must run a ground wire.
    metal conduit you can use the conduit as ground, as long as all fittings and connectors are tight, and use wire pig tails at the outlet box. Attach the pigtails to the outlet box with screws in the back of the box then attach them to the device.
    I always run a ground wire even in metal conduit just for safety.
    No way would i ever use the structure as a ground for electric equipment.

    Hope this helps,

    Huck

    Comment


    • #3
      Re: new guy here. signed up to ask a question about neutral and ground.

      welcome Allen,

      I am not even a electrician and I agree with huckster4, run a ground to the receptacles,
      Push sticks/blocks Save Fingers
      ~~~~~~~~~~~~~~~~~~~
      "The true measure of a man is how he treats someone who can do him absolutely no good."
      attributed to Samuel Johnson
      ~~~~~~~~~~~~~~~~~~~
      PUBLIC NOTICE: Due to recent budget cuts, the rising cost of electricity, gas, and oil...plus the current state of the economy............the light at the end of the tunnel, has been turned off.

      Comment


      • #4
        Re: new guy here. signed up to ask a question about neutral and ground.

        Hmm,
        Well guys, Like I said, this job is entirely metal.
        EMT conduit with metal connectors and stranded wire, not romex, metal boxes, metal faceplates etc. all bolted with metal self drilling screws to the metal framing. I just thought that since the ground wire would only serve to duplicate the path that the building structure would provide I could do without it.

        "metal conduit you can use the conduit as ground, as long as all fittings and connectors are tight, and use wire pig tails at the outlet box. Attach the pigtails to the outlet box with screws in the back of the box then attach them to the device."

        This is what I was thinking. Am I not correct in thinking that the only time there would be any electricity in the building itself would be if I had a defective tool of some sort, ie a drill that was shorted internally?

        Just asking to learn ya know.

        Comment


        • #5
          Re: new guy here. signed up to ask a question about neutral and ground.

          Any number of things can go wrong.Some thing short out,motor windings go bad.
          Even where u possibly get something wired wrong and end up with reverse polarity.
          I have had instances of reverse polarity on an ungrounded system which energizes the structure.AAAACK!
          Running a seperate ground wire ensures the safety factor.

          Huck

          Comment


          • #6
            Re: new guy here. signed up to ask a question about neutral and ground.

            I'm not an electrician either, but I've done a lot of residential wiring over the years, as well as some tool, motor, and electronic things. I agree with the previous posters.

            With a metal building, I think you really need the safety factor designed into regulation wiring components and I'd wire it just like I would any other structure. Actually, I think I would be more concerned with NOT having a proper ground wire and grounding practices and whether I might need something extra, just to guard against accidentally energizing the structure. I wonder what the NEC has to say about wiring in a metal structure?

            I hope this helps,

            CWS
            Last edited by CWSmith; 02-11-2011, 08:25 PM.

            Comment


            • #7
              Re: new guy here. signed up to ask a question about neutral and ground.

              I know in the past the EMT has been acceptable as a ground, but it is amazing how many times one can fine over the years, conduit that has separated.

              I am not up on the current code, but I would venture to guess all the receptacles are to GFIC as well,

              and if animals are to be in the barn there are special grounding and bonding requirements that come in to play as well,
              most of the requirements are to deal with stray voltages, as animals are very supticable to stray voltages even if there only in micro volts,
              Push sticks/blocks Save Fingers
              ~~~~~~~~~~~~~~~~~~~
              "The true measure of a man is how he treats someone who can do him absolutely no good."
              attributed to Samuel Johnson
              ~~~~~~~~~~~~~~~~~~~
              PUBLIC NOTICE: Due to recent budget cuts, the rising cost of electricity, gas, and oil...plus the current state of the economy............the light at the end of the tunnel, has been turned off.

              Comment


              • #8
                Re: new guy here. signed up to ask a question about neutral and ground.

                Hmm.
                I guess I'd better buy some more wire then.

                Thanks all.

                allen

                Comment


                • #9
                  Re: new guy here. signed up to ask a question about neutral and ground.

                  Hold on there Texan. If you are using EMT, you don't have to pull a ground wire. I would, but you don't have to if you don't want to. This has nothing, zero, zip to do with the building being metal. Same rules for stick construction.

                  Metal buildings must be bonded to the electrical system but are not good ground fault paths like metalic raceways (conduit) and grounding conductors (wire).

                  Do you have a service or feeder supplying power to the structure? Do you plan on boarding/raising any livestock?
                  Remember there are specific rules for animal holding areas and must be addressed. This is an NEC matter and should be consulted before doing any installations.
                  Licensed Electrician

                  Comment


                  • #10
                    Re: new guy here. signed up to ask a question about neutral and ground.

                    John,
                    I'm out in the country and this is my workshop. no animals.
                    I took a VOM today and checked my ground and neutral. They are common throughout the building.
                    I am running a dedicated neutral to all fixtures/outlets etc. I just didn't think I needed the ground.

                    I built a room inside the barn and wired it and it is all romex , 12/2 w ground and everything has a ground because it is wood construction.

                    My load center is fed with a 200 amp breaker and has two hots and a neutral. the building is bonded and grounded with 4 eight foot ground rods driven into the ground and a number 4 solid copper is welded to the structural steel.

                    I've done it all myself. There is nothing making the building live and no wiring uses the structure for a return.
                    All switches I use will ground when I screw them to the metal boxes. same for the outlets.

                    I was just trying to save a bit of money on copper.

                    Oh yeah. my wire is 14 , 12 and 10 gauge stranded THHN

                    I don't know what NEC is
                    Last edited by allen in texas; 02-12-2011, 08:51 PM. Reason: to ask another question

                    Comment


                    • #11
                      Re: new guy here. signed up to ask a question about neutral and ground.

                      the NEC it the "national electrical code" it is the electrician's bible, and gives one the rules and tables, and the no no's in wiring, it is or a version of it is usually adopted by a state (come out ever three years), and is considered law, and if one was to pull a permit and an inspector comes by to inspect the job done, they would be using the NEC, that was adopted by the state or local jurisdiction, and if things were not done that the NEC said was to have been done or the wrong size or type of wire used, you would fail inspection and the power company would not hook up power to the building or place until all the problems were corrected. In some areas one can not sell a place or property until all things meet the code, in most locations to be legal one is to pull a permit before wiring and follow the inspection requirements, most allow one to do there own wiring, but the permit and inspection is usually required to meet state and local laws and usually the insurance company may require it as well, or they may not pay for a loss if it found to be caused by the wiring.
                      Push sticks/blocks Save Fingers
                      ~~~~~~~~~~~~~~~~~~~
                      "The true measure of a man is how he treats someone who can do him absolutely no good."
                      attributed to Samuel Johnson
                      ~~~~~~~~~~~~~~~~~~~
                      PUBLIC NOTICE: Due to recent budget cuts, the rising cost of electricity, gas, and oil...plus the current state of the economy............the light at the end of the tunnel, has been turned off.

                      Comment


                      • #12
                        Re: new guy here. signed up to ask a question about neutral and ground.

                        Thanks BHD.

                        OP. Pulling a ground wire into a metal conduit is a matter of choice and to some a safety issue. The NEC allows this wiring method. But connectors and couplings can come apart. Once this occurs, the only path for the unwanted current will be the physical body (you) or the structure. I sure would not want to rely on the structure as my equipment grounding conductor (EGC).

                        Bonding and grounding are two separate things. You bond the metal building to protect it and its contents from lightning strikes. You ground the system to protect people.

                        If you decide not to pull the ground wire (It would be silly IMO if you did not pull/push one) you must still pigtail a grounding jumper from each metal box to the device placed in the box. Since you already have conduit, it would be simple to put in the extra wire. You could most likely just push it in with the existing wires in place.
                        Licensed Electrician

                        Comment


                        • #13
                          Re: new guy here. signed up to ask a question about neutral and ground.

                          I was planning to pigtail all the outlets and switches to the boxes but I guess now I'll just buy some more wire.
                          I haven't pulled it all in yet.

                          Can I use bare wire or does it need to be insulated?

                          Comment


                          • #14
                            Re: new guy here. signed up to ask a question about neutral and ground.

                            Originally posted by allen in texas View Post
                            I was planning to pigtail all the outlets and switches to the boxes but I guess now I'll just buy some more wire.
                            I haven't pulled it all in yet.

                            Can I use bare wire or does it need to be insulated?
                            Use insulated green THHN. Same as what you already have. Theoretically you could use wire that is not insulated in the conduit. But just use whats available. Insulated.
                            Licensed Electrician

                            Comment


                            • #15
                              Re: new guy here. signed up to ask a question about neutral and ground.

                              Wow, another color.
                              I was having trouble keeping black and white straight. Now I gotta have green. Oh well, if you guys say so.

                              Off to Lowes for more wire.
                              Actually, it's only going to be about another $45 or so for the wire.
                              Thanks all.

                              I guess I should have decided to wire it with three to begin with and I would have been sure.
                              But if you never ask, you never learn.
                              Still the neutral in ground are going to be common both at the load center and throughout the building. But the ground will not carry anything unless I have something fail so to my thinking, the building will never be energized.

                              Comment

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