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    more than 360 in a conduit run

    OK, so I'm freaking out a bit here. Three years ago when I redid my backyard and put in a pool I put a 2" PVC conduit in from my main electrical panel about 120' to an area of my lot I'd like to eventually build a guest-house. (thinking ahead!) It basically goes underground, winds around a bit and ends up roughly in the middle of where I thought the pad would be.

    So now we're getting to the build of the guest house and it occurs to me that I've already got 330 degrees of bends in the route and I'm likely to need another 45 and then a sweep up to my electrical panel. That's 330+45+90=465 degrees! (FWIW, the conduit currently still terminates underground at 330 degrees. I still have to uncover the end and run the extra 90+45).

    So I'm freaking out that all my forethought is for not. I put in a full 2" PVC even though I'm only running 125 A just in case.

    Am I'm screwed here? Should I buy #1 copper instead of #2/0 Al just to make sure things can run. Will that even work? What should I do?

    #2
    Place a pull-box at the present pipe end, whether you use it for the pull or not.
    Master Electrician
    Electrical Contractor
    Richmond, VA

    Comment


      #3
      If you are going to be rejected by an inspector on this you have a problem. If not might want to use super slick type conductors (SIMpull for example) and even then maybe use additional lubricant. I've seen pulling difficulty for XLPE type insulation in underground PVC go from moderate but doable for hand pulling to needing mechanical pulling method just by having three 90 degree bends instead of two.
      I live for today, I'm just a day behind.

      Comment


        #4
        Thanks. Couple of followups:
        1. Would you guys spring for the #1 CU over the #2/0 Al given the situation. It's an extra $400 for approx 150 feet.
        2. The current end is 4' underground. Can a pull box extend that far down?
        3. The inspections will be fine. The previous run was inspected and passed.
        4. Could I uncover the current end, pull the wires through with a lot of slack, and then assemble the remaining conduit OVER the wires. Might be cumbersome, but we're talking about digging up $10k worth of landscaping if I can't get this wire through.....

        Comment


          #5
          4. Technically, no. The raceway must be complete before the wire is pulled.

          Sent from my XT1585 using Tapatalk

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            #6
            Originally posted by rszimm View Post
            OK, so I'm freaking out a bit here. Three years ago when I redid my backyard and put in a pool I put a 2" PVC conduit in from my main electrical panel about 120' to an area of my lot I'd like to eventually build a guest-house. (thinking ahead!) It basically goes underground, winds around a bit and ends up roughly in the middle of where I thought the pad would be.

            So now we're getting to the build of the guest house and it occurs to me that I've already got 330 degrees of bends in the route and I'm likely to need another 45 and then a sweep up to my electrical panel. That's 330+45+90=465 degrees! (FWIW, the conduit currently still terminates underground at 330 degrees. I still have to uncover the end and run the extra 90+45).

            So I'm freaking out that all my forethought is for not. I put in a full 2" PVC even though I'm only running 125 A just in case.

            Am I'm screwed here? Should I buy #1 copper instead of #2/0 Al just to make sure things can run. Will that even work? What should I do?

            Legally you are only allowed 360 degrees of bend between pull points.

            If you are willing the break the rules and live with the shame and guilt of it then you can probably pull the conductors in with little or no problem if you made all your connection up correctly.

            A lot of problems with pulling wire is that most people don't know (because of a lack of experience ) how to pull wire. Even how you make up the head on a wire pull can make all the difference between and easy pull and a hard pull.

            Make up a good head that won't get caught, use plenty of lubricant, make sure you have someone to feed that's not afraid to push the cable into the conduit and then take it slow and easy.
            The 95% of people that you can't trust give the other 5% a bad name.

            Comment


              #7
              Originally posted by rszimm View Post
              The current end is 4' underground. Can a pull box extend that far down?
              Can you use your remaining 30 degrees of bend to shallowly start rising to reach a reasonable pull box depth?

              The pull box could go anywhere after 105 degrees of bend from the start, so that you have 360 degrees or less between the pull box and the guest house. Is there somewhere else in that portion of the run where it would be easier to add an inline pull box?

              Also, not sure if this is something anyone would ever do, but in the portion of the run that is between 195 degrees and 270 degrees of bend from the start, you could dig down to the conduit, cut out a section, add 90s to each end to come to grade, and add a pull box there. Then each side of the pull box is under 360 degrees of bend.

              Cheers, Wayne

              Comment


                #8
                One possibility could be to dig down somewhere in the middle of the run that would have a 465 degree cumulative angle after your 45 and 90 elbows are added in. Then you could cut the conduit, attach a 90 to each side, and then bring two conduit stubs up to an above ground pull box. This would result in 465 + 90 + 90 = 645 degrees that is split between 2 conduit runs. If you're lucky there's a suitable place where each run can be 360 or less. For example 360 and 285, 330 and 315, etc.
                This proposal would take a little digging but much less than starting over.

                Another thing to make pulling easier is to use two 45's to make a 90, or even better get the larger radius elbows (although they're more costly and harder to get).

                Comment


                  #9
                  Wayne beat me to it

                  Comment


                    #10
                    1) A pull box can be 4 feet down if you can get down there to do the pull. Think 'vault'. Probably not worth it for you but certainly doable.

                    2) Every bend in a conduit is a pull force multiplier, that is why you are restricted to a certain number of bends. If you can push the cable past a pull point then it won't add friction to the pull. While code does not recognize this as a way to put an extra bend in a run, you should know this as a technique to reduce wire tension on any run you pull. Look up the capstan equation to understand this. https://en.wikipedia.org/wiki/Capstan_equation

                    -Jon

                    Comment


                      #11
                      You can bury the pull box if you can comply with the accessibility exception. You need some kind of marker for the future access.

                      314.29 Boxes, Conduit Bodies, and Handhole Enclo-
                      sures to Be Accessible. Boxes, conduit bodies, and hand-
                      hole enclosures shall be installed so that the wiring con-
                      tained in them can be rendered accessible without removing
                      any part of the building or structure or, in underground cir-
                      cuits, without excavating sidewalks, paving, earth, or other
                      substance that is to be used to establish the finished grade.
                      Exception: Listed boxes and handhole enclosures shall be
                      permitted where covered by gravel, light aggregate, or non-
                      cohesive granulated soil if their location is effectively iden-
                      tified and accessible for excavation.
                      Rob

                      Moderator

                      All responses based on the 2014 NEC unless otherwise noted

                      Comment


                        #12
                        Instead of tearing up $10k of landscaping, hire a directional boring contractor to install a straighter run, or route it to a place where you can put a pull/junction box if they can't get it straight enough.
                        I live for today, I'm just a day behind.

                        Comment


                          #13
                          Originally posted by LarryFine View Post
                          Place a pull-box at the present pipe end, whether you use it for the pull or not.
                          Ditto. Sometimes the answer is pretty easy...

                          Comment


                            #14
                            Originally posted by rszimm View Post
                            Would you guys spring for the #1 CU over the #2/0 Al given the situation. It's an extra $400 for approx 150 feet.
                            I've seen enough corroded aluminum conductors pulled out of buried conduit to always want copper. All it takes is a tiny nick or pinhole in the insulation for wet aluminum wires to start self-destructing. And if the conduit is underground, the wires will be wet.

                            If you can afford $10K landscaping, I imagine you can afford $400 for the peace-of-mind of having copper.

                            Comment


                              #15
                              Originally posted by Jon456 View Post
                              I've seen enough corroded aluminum conductors pulled out of buried conduit to always want copper. All it takes is a tiny nick or pinhole in the insulation for wet aluminum wires to start self-destructing. And if the conduit is underground, the wires will be wet.

                              If you can afford $10K landscaping, I imagine you can afford $400 for the peace-of-mind of having copper.
                              Fantastic! So I think I'm coming to a plan of a pull box that I'll bury and identify where it's buried, and run the #1 Copper because it's easier to bend and less likely to corrode.

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