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  • Wire size question

    Hi everyone.

    I am wiring my shop using PVC conduit. I may be able to get a really good deal on some T90 wire in 12 gauge. However, the seller doesn't have any white 12 gauge, only 14. Can I use a black 12 gauge and a white 14 gauge for a 15 amp circuit? Or must they be the same. Maybe a dumb question but that stuff's really expensive so if I can use it I'd like to.

    Thanks.
    Regards

    Barry


    "That's why I love my computer,,,,,,,, my friends live in it."
    - Colin Greg,
    Barnsley, South Yorkshire, England

    "Yes, cheap pens can be made. I don't make them."
    - Daniel, Reno, NV

  • #2

    Re: Wire size question

    Re: Wire size question

    doesnt matter, a 15 amp circuit requires at least a 14 guage so 12 is ok too
    the hot size versus neutral size has no bearing at all
    my shop is a beaver lodge
    steve, sarnia, ont

    sigpic

    1940's Beaver Jointer

    Comment


    • #3

      Re: Wire size question

      Re: Wire size question

      Originally posted by Barry in London View Post
      Hi everyone.

      I am wiring my shop using PVC conduit. I may be able to get a really good deal on some T90 wire in 12 gauge. However, the seller doesn't have any white 12 gauge, only 14. Can I use a black 12 gauge and a white 14 gauge for a 15 amp circuit? Or must they be the same. Maybe a dumb question but that stuff's really expensive so if I can use it I'd like to.

      Thanks.
      As SteveM said, the conductors don't have to be the same size, they just have to be big enough for the load and small enough for the conduit. Since it's PVC conduit and you're using individual conductors, though, I'm wondering what you're using for a bonding strip? I've found in the past that it's often simpler to just run NMD-10 or something of that nature through the conduit, then you have all of the conductors that you need, and often with less waste due to the common need for NMD-10.
      Mike in Orangeville, ON
      http://ifonlyyouwood.blogspot.com/

      SPCHT

      Comment


      • #4

        Re: Wire size question

        Re: Wire size question

        Originally posted by Mike Graham View Post
        As SteveM said, the conductors don't have to be the same size, they just have to be big enough for the load and small enough for the conduit. Since it's PVC conduit and you're using individual conductors, though, I'm wondering what you're using for a bonding strip? I've found in the past that it's often simpler to just run NMD-10 or something of that nature through the conduit, then you have all of the conductors that you need, and often with less waste due to the common need for NMD-10.
        Steve, thanks for the response. I figured that would be the case but wasn't sure.

        Hi Mike.

        I would prefer to use NMD-90 but I've been advised against it because of fill limit. My main run of conduit is 1.25", narrowing down to 1" at the T's. The drops from there are either .75" (for 1 cable) or 1" (for 2 cables). I'm running three 15A circuits and one 20A circuit through that main conduit. I may put in one additional 15A circuit. I tried figuring out all the tables for fill capacity but I guess I'm just dumb as dirt when it comes to that cause I couldn't understand it. I've read through the archives and it's been recommended in the past to not run cable but to instead run individual wires like R90 or T90. I have run so many searches for help with using PVC conduit but there isn't much out there. I am confident in my abilities to wire everything but I don't want to break any fill capacity rules or other rules I'm not aware of. I realize it would have been simpler (and cheaper) to run the wire on the surface but it didn't look neat enough for me.
        Last edited by Barry in London; 07-14-2008, 10:25 AM. Reason: Added sentence.
        Regards

        Barry


        "That's why I love my computer,,,,,,,, my friends live in it."
        - Colin Greg,
        Barnsley, South Yorkshire, England

        "Yes, cheap pens can be made. I don't make them."
        - Daniel, Reno, NV

        Comment


        • #5

          Re: Wire size question

          Re: Wire size question

          Originally posted by Barry in London View Post
          I would prefer to use NMD-90 but I've been advised against it because of fill limit.
          How much wire are we talking about, here? It's surprisingly easy to strip the sheath off of the wires. If we're only talking about 50' or so then personally I'd just do that. It's often cheaper than buying the individual conductors in reasonable lengths.
          Mike in Orangeville, ON
          http://ifonlyyouwood.blogspot.com/

          SPCHT

          Comment


          • #6

            Re: Wire size question

            Re: Wire size question

            i agree with mike, and i do it myself, thecable supplying outlets in my shop all drop down from the ceiling n conduit and i removed the outer casing for ease of pulling
            and yes the inspector approved them
            my shop is a beaver lodge
            steve, sarnia, ont

            sigpic

            1940's Beaver Jointer

            Comment


            • #7

              Re: Wire size question

              Re: Wire size question

              Originally posted by Mike Graham View Post
              How much wire are we talking about, here? It's surprisingly easy to strip the sheath off of the wires. If we're only talking about 50' or so then personally I'd just do that. It's often cheaper than buying the individual conductors in reasonable lengths.
              Probably 125 - 150 feet max. I thought about doing that because I have a roll of 14-2 and 12-2. I was told that I can't use the bare ground wire in the cable and that I'd have to use the green insulated wire (T90). But since I only need to run one ground, it wouldn't be too expensive to buy 50 or 60 feet.

              I do have one run of 3/4" conduit for the lights. Can I run two 14-2 cables inside that without exceeding the fill capacity? If so, how much cable sheathing is permitted in the box. I know with metal boxes they don't like to see more than 1/2". I can strip that too but if I don't have to I don't want to.

              Thanks for the help.
              Regards

              Barry


              "That's why I love my computer,,,,,,,, my friends live in it."
              - Colin Greg,
              Barnsley, South Yorkshire, England

              "Yes, cheap pens can be made. I don't make them."
              - Daniel, Reno, NV

              Comment


              • #8

                Re: Wire size question

                Re: Wire size question

                Originally posted by Barry in London View Post
                Probably 125 - 150 feet max. I thought about doing that because I have a roll of 14-2 and 12-2. I was told that I can't use the bare ground wire in the cable and that I'd have to use the green insulated wire (T90). But since I only need to run one ground, it wouldn't be too expensive to buy 50 or 60 feet.
                They won't let you use the bare bonding strip in PVC conduit? That surprises me. I don't have the residential code handy, but I'm pretty surprised by that, indeed.

                I'll have to get back to you on the conduit fill question, as I don't have the tables at home.
                Mike in Orangeville, ON
                http://ifonlyyouwood.blogspot.com/

                SPCHT

                Comment


                • #9

                  Re: Wire size question

                  Re: Wire size question

                  i used the bare ground conductor in my shop inside the pvc conduit, no prob with inspection
                  conduit fill never came up but most of mine are split circuits fed by 2 hots, common neutral and the ground in 3/4 conduit
                  each drop from the ceiling ends with a pvc box with 2 split receptacles in each
                  eachdouble pole breaker feeds two of these receptacle boxes and i have 4 of those double pole breakers, so 8 drops and thus 16 split receptacles
                  it sounds like a lot i know but in most shops its a real pain to keep plugging in tools, so everything is always plugged in and no powerbars(most of them arecrap anyway) or those 6 into one blocks either, and no extension cords!!
                  the splits are probably over kill but i can plug in a big router and the shop vac into same receptacle and not over load the circuit
                  my garage is insulated and drywalled so running electrical in the walls was not an easy option, surface mounted boxes and conduit was an easy option.
                  all lighting is ceiling mounted florescents plus a ceiling fan, the florescents are connected with 14-2 exposed between the fixtures, no mechanical protection required but the distance between the lamps is only a foot or so
                  allof this was inspected and approved
                  my shop is a beaver lodge
                  steve, sarnia, ont

                  sigpic

                  1940's Beaver Jointer

                  Comment


                  • #10

                    Re: Wire size question

                    Re: Wire size question

                    Thanks guys!

                    Steve, my shop is insulated and has 5/8" OSB on the walls so putting the wires in the walls wasn't an easy proposition. Surface mounting was way easier but I didn't like the look of wire strung all over the place so I went with conduit. I used PVC because it was way cheaper than EMC and much easier to work with.
                    Regards

                    Barry


                    "That's why I love my computer,,,,,,,, my friends live in it."
                    - Colin Greg,
                    Barnsley, South Yorkshire, England

                    "Yes, cheap pens can be made. I don't make them."
                    - Daniel, Reno, NV

                    Comment


                    • #11

                      Re: Wire size question

                      Re: Wire size question

                      yeah pvc is the way to go, home depot has all kinds of boxes, bends and the pipe is cheap and the whole things gives great protection and is easy to install, my inspector said not to bother glueing the conduit if its inside a building, so changes are easy
                      my shop is a beaver lodge
                      steve, sarnia, ont

                      sigpic

                      1940's Beaver Jointer

                      Comment


                      • #12

                        Re: Wire size question

                        Re: Wire size question

                        Steve, where were you two weeks ago when I started gluing my conduit!! I didn't want to but figured the inspector would fail me if I didn't. I hope my inspector is so accommodating! I didn't glue the ceiling conduit as I'm thinking about putting in a spot light fixture over my workbench and may put in a ceiling fan at some point down the road.

                        Just curious, when I called ESASafe I was told the inspection cost $69.00 for up to 11 fixtures and well over $100.00 for 12 to 40. Do you know if a double receptacle is considered one fixture or two? And I presume a switch is a receptacle. I'm sitting at 12 now if double's are counted as 1 and switches are counted as 1. If so I may take one receptacle out and put it back in later. (But don't tell anyone! )
                        Regards

                        Barry


                        "That's why I love my computer,,,,,,,, my friends live in it."
                        - Colin Greg,
                        Barnsley, South Yorkshire, England

                        "Yes, cheap pens can be made. I don't make them."
                        - Daniel, Reno, NV

                        Comment


                        • #13

                          Re: Wire size question

                          Re: Wire size question

                          Originally posted by Barry in London View Post
                          Steve, where were you two weeks ago when I started gluing my conduit!! I didn't want to but figured the inspector would fail me if I didn't. I hope my inspector is so accommodating! I didn't glue the ceiling conduit as I'm thinking about putting in a spot light fixture over my workbench and may put in a ceiling fan at some point down the road.
                          Just as an aside, and it's common sense and maybe doesn't need to be mentioned, but I deal with an ESA inspector regularly, and I've found that the best course of action is to be aboveboard and just let him do his thing, agree to everything he says, write it down, even, in a notebook, though he may tell you not to bother because you get a report at the end of it, and generally act like you're actually going to take his advice, and things go just fine. Push back and your life gets hard.
                          Mike in Orangeville, ON
                          http://ifonlyyouwood.blogspot.com/

                          SPCHT

                          Comment

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