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  • My THHN is too short

    Hi Guys,

    I'm changing the backyard around and moving my spa. As a result, I want to relocate the GFI box to a new location. But, if I do that, the #6 wire will be too short to run to the new location.

    That wire costs a bundle, and it will be about an 80 foot run. My question is, is there any good (code-approved?) way to splice the wire without having the splice in an accessible box? i.e., the splice would be in the conduit. Solder with heat shrink? Solder with liquid tape? I don't have any idea if this is even possible.

    I'm not too worried at all about pulling the splice. I'll put teflon sleeving around it, and it'll be a dead straight run with a 90 degree sweep bend at each end. I've got a load of 2" PVC conduit that I plan to use, which is way too big but I need to use it up anyway. It's 3 #6 conductors and a #8 ground.

    Thanks in advance for any ideas. It would be very nice to avoid having the box, which would end up in the middle of a new lawn.

    -Andy

  • #2
    Re: My THHN is too short

    #6 THHN is less than $.41 a foot right now. Which for an 80 foot run will cost you about $100 to do right, plus your ground.

    There is no code legal splice you can make in a conduit. You either need to re-pull it, put in a junction box, or go underground where you can use an underground splice kit, but your THHN can't go underground so that option is out as well.

    Jeff

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    • #3
      Re: My THHN is too short

      Hi Jeff,

      Thanks for the info. I had never heard of a legal splice w/o a box, but thought I would ask the experts "just in case".

      I wasn't aware that thhn was so cheap. For some reason I was thinking it was a lot more than that... has it dropped over the past year or am I remembering wrong? In any case, at $.41, no question, I'll just pull some new wire.

      Thanks again,

      -Andy

      Comment


      • #4
        Re: My THHN is too short

        Hang on a minute, I'll send my apprentice over with the wire stretcher....Best invention ever made.

        Comment


        • #5
          Re: My THHN is too short

          Originally posted by Andy_M View Post
          Hi Jeff,

          Thanks for the info. I had never heard of a legal splice w/o a box, but thought I would ask the experts "just in case".

          I wasn't aware that thhn was so cheap. For some reason I was thinking it was a lot more than that... has it dropped over the past year or am I remembering wrong? In any case, at $.41, no question, I'll just pull some new wire.

          Thanks again,

          -Andy
          Copper has dropped like a rock over the last 5 or so months. You are correct, a year ago that would have been a pricey thing to re-do, today, not so much. As the market crashes, so do commodities, which brings copper down with it.

          Jeff

          Comment


          • #6
            Re: My THHN is too short

            Originally posted by piette View Post
            Copper has dropped like a rock over the last 5 or so months. You are correct, a year ago that would have been a pricey thing to re-do, today, not so much. As the market crashes, so do commodities, which brings copper down with it.

            Jeff
            Now that is some good news. I haven't priced wire for some time. Maybe now I'll get busy this spring and fix things up around The Woussko Hut as they should be.

            Comment


            • #7
              Re: My THHN is too short

              Cute "wire stretcher" comment. Yes I'm an apprentice, but not for long!
              The short answer, yank the wire out, reroute the conduit, (which I'm going to assume is PVC) with a sawsall, and run a new curcuit. No splices, no problem.

              Anyrate, for the rest of you I have a related question. With conduit ran underground, again say PVC, do the conductors have to have a THWN rating, not just THHN? I'm finishing up my NEC classes this semester and going on to take the big test, and I do remember my professor mentioning something about this.
              Last edited by tailgunner; 02-20-2009, 06:50 PM.

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              • #8
                Re: My THHN is too short

                Most THHN/THWN is dual rated. THHN is for dry locations only. If the wire is not rated THHN/THWN it cannot be used in wet locations such as underground PVC. Even if the PVC was watertight along its' underground length you would still have condensation to contend with. I personally have never pulled wire out of underground PVC that wasn't wet.

                Comment


                • #9
                  Re: My THHN is too short

                  Originally posted by killavolt View Post
                  Most THHN/THWN is dual rated. THHN is for dry locations only. If the wire is not rated THHN/THWN it cannot be used in wet locations such as underground PVC. Even if the PVC was watertight along its' underground length you would still have condensation to contend with. I personally have never pulled wire out of underground PVC that wasn't wet.

                  I was lazy. My wire is dual rated... I think the thhn is all thhn/thwn at Lowes or H-D. At least all that I've gotten is.

                  I agree with killavolt's comments about the wetness in underground PVC. However, when I pulled my existing #6 conductors out, they were bone dry. I don't do this every day like you guys, but that is the first time I've seen 'em dry - they're usually dripping.

                  -Andy

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                  • #10
                    Re: My THHN is too short

                    Andy

                    Try pricing #6 type THHN/THWN at a good electrical supply house. Also price 100 feet of #8 type THHN/THWN as well for grounding. You should be able to buy the #6 in black, red and white and the #8 in green. You might ask if it's cheaper to buy a single 250 foot piece of #6 in say black or white and then use color coding tape on the ends after you cut it into 3 pieces.

                    250 / 3 = a little over 83 feet per piece

                    In all too many cases you'll find Home Depot and Lowes are NOT the place to buy any serious electrical supplies. You might want to call the counter at several electric supply houses, let them know this is a CASH purchase (take the green stuff) and price cut pieces of the above wire. Sometimes you can get lucky and find where they have some leftover pieces they want to be rid of. As long as you can use them, you save some $$$. Let's say they have 87 feet and 174 feet of #6. You can cut the 174 foot piece into 2 length as needed and cut the 87 footer too. You will have some left over pieces, but they can come in very handy if you ever want to install a receptacle for a welder in your shop. Sometimes they (supply houses) give better prices when you buy their scraps.

                    HINTS: Take a 100 foot tape measure and be sure how long you need each piece of wire. Always allow a few feet extra just in case Murphy's Law comes into play. Then add things up. Let's say you really want 3 x 82 feet of #6 and 1 x 82 feet of #8 for grounding and 15 feet of something in green to run to a ground rod. In this case you really want to get 100 feet of #8 green. For the #6 wires you could make use of a 250 foot piece of any color #6 and cut it to 3 lengths. Then use the color coding tape. Use a 6 Volt lantern battery connected to 2 of the wires at one end and a Volt meter to check the other ends. You can figure your colors easy this way. You'll need to connect it up several times but if you think this through you'll see how simple it is. This is done once the wires are pulled through the conduit.

                    Maybe it's best not to do things this way and just pay a little more for proper wire in the right colors. It sure makes a nicer looking job when done.

                    Sorry if all this is confusing. It's that sometimes you can save good $$$ thinking things though some.
                    Last edited by Woussko; 02-20-2009, 01:42 AM.

                    Comment


                    • #11
                      Re: My THHN is too short

                      Like Woussko said, call and get the price from a supply shop. My local supply shop tells me NOT to buy anything smaller than #2 from them, they simply can not compete with the buying power of Home Depot or Lowes. The big box stores buy and sell so much wire, plus they adjust price to current market price not what they bought it at. The supply shops sell at a fixed price they bought at, so if they bought high, they sell high.

                      Perfect example: My local supply shop right now for a 250 ft roll of 14-2 romex is at $42, Home Depot for a 250 ft roll of romex is at $24. That is a huge diffrence. Same brand and all, Simplex SimPull.

                      I haven't seen THHN that isnt dual rated THHN/THWN in quite some time.

                      Jeff

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                      • #12
                        Re: My THHN is too short

                        Originally posted by Woussko View Post
                        Andy

                        Sorry if all this is confusing. It's that sometimes you can save good $$$ thinking things though some.
                        Thanks for your comments! Actually, I often do exactly what you've explained.... hunting eBay auctions! Often folks auction off lengths of wire left over from other jobs and as you point out, if you know exactly what lengths you need you need you can sometimes make a buy. The thing about eBay though is that you need to know the going price or you can take it in the shorts, as they say, because not all the prices are good. And copper, being heavy... you have to figure in the cost of shipping. Sometimes you can win pretty big, but other times the prices with shipping are way too high. In this case, without the heads up from Jeff on the dropping price of wire, I probably would spent waaay too much!

                        I need to go to the electrical supply for a condulet anyway (same price as Home Depot and the electrical supply has ALL the varieties) so I'll make a point to check on the wire pricing. Last time I did, though I had the exact same sitiuation Jeff mentioned. The supply house wasn't even close to Lowe's price (and Lowe's was a touch cheaper than H-D). But it sure can't hurt to price it out every so often.

                        I always try for actual red, black, white & green. To me, it's just the right way to do it. But I do have all the colors of tape.... I often can't find larger sizes in the correct colored insulation, it seems those easiest to find in black. But the #6 for this project... shouldn't be a problem.

                        Thanks again! Great advice from everyone. But I called around to find one of those wire stretchers and they all thought I was nuts.....

                        Comment


                        • #13
                          Re: My THHN is too short

                          Originally posted by piette View Post
                          I haven't seen THHN that isnt dual rated THHN/THWN in quite some time.

                          Jeff

                          I know all Southwire's "THHN" is dual rated (Actually multirated THHN/THWN/MTW)
                          John from Baltimore
                          "One day at a time"

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