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    Hey guys,
    I was wondering if anyone out there had a copy of the NEC. I have an inspector telling me I can't run a 20 amp 240 air compressor circuit on 12-2 and reidentify the white as black. He stated that I needed to run 12-3. If my internet search on the Pass & Seymour web was correct, NEC Sec 200-7 covers this but they do not go into enough detail on the website regarding this issue.

    I know the inspector is always right!!........ but in this case I am pretty sure that he is wrong and him being wrong means more money out the door on a roll of 12-3.

    Wiring in the new shop and garage is complete. I ran 6-3 for the welder and 8-3 for the RV hookup. Have a total of 58 electrical openings for 960 sqr ft. Should be able to find an outlet or a light at most every turn. I plan on throwing in a mess of insulation tomorrow.

    Your help is appreciated...
    Best Regard,
    __________________
    Jesse
    aka Neo

    Miller Passport
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    Wish list:
    Maxstar 150STH or
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    A Dynasty 300 if I am wishing really hard..

  • #2
    Well, some black electrical tape on the white wire will identify it to any would be electrician the wire is hot. Now I dont see the deal with the 12/2 -12/3 wire as you only have two hots ?

    FWIW, my compressor is only 16amps running and it will be going on a 10/2 dedicated circuit.

    Anybody off hand know if say a 50' run for my compressor will have to much voltage drop on start up or running for the 10ga wire? TIA.

    Comment


    • #3
      Ray,
      According to my chart, a 50" run of 10ga copper should handle 45 amps 240volt with 2% voltage drop.


      The information I have says that a branch circuit to an individual motor should be selected on the basis of carrying.125% of the full load current of the motor.

      The generic chart that I have shows that a 5hp single phase 240v motor should have a full load amperage of 28 amps, so you would size your wire for 35 amps
      Jeff

      Comment


      • #4
        Just a few months ago I had to wire my daughter’s well house. I wasn’t totally convinced I had done every little detail to code. I knew there were a couple licensed electricians working on my daughter house about 150-feet away. I asked if one of them would walk down and give the well house the once over. The electrician explained to me how the NEC was written. The inspector has the authority to over ride the code, no matter what! His word is law. I thought this was very strange , but the electrician said it was a fact of life in the electrical world.
        If the inspector says to change it, save your self some headaches and do it his way!

        Comment


        • #5
          Originally posted by x-ray View Post
          Anybody off hand know if say a 50' run for my compressor will have to much voltage drop on start up or running for the 10ga wire? TIA.
          Here you go Ray. The electrical inspector I was dealing with on my daughter’s well house suggested this web site for a voltage drop calculator. One thing he told me about voltage drop, he has no authority over it. It’s all up to the owner to install the proper size wire for voltage drop. Learn sumthing everyday!


          http://www.stanselectric.com/page3.html

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          • #6
            Wiring for a compressor

            Hate to tell you but the inspector is right! The reason two wire stuff is on the store shelf is because of price! Remember - When you can afford to you can afford not to.
            Think Alot
            Learn Alot
            Read Alot
            And Then Do It Again & Again

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            • #7
              When I was doing sign work in Az. the electrical inspector would approve coloring the white wire with magic marker but he said its not really right and preferred that we use the correct wire coloring. Like Pile Buck said, they are the last word and what they say goes.
              To all who contribute to this board.
              My sincere thanks , Pete.

              Pureox OA
              Westinghouse 300 amp AC stick
              Miller Syncrowave 250
              Hexacon 250 watt solder iron

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              • #8
                Originally posted by leeschaumberg View Post
                Hate to tell you but the inspector is right! The reason two wire stuff is on the store shelf is because of price! Remember - When you can afford to you can afford not to.
                What do you hook the third wire up too?


                Thanks guys for the voltage drop info

                Pile thanks for that online calculator!

                Comment


                • #9
                  Originally posted by x-ray View Post
                  What do you hook the third wire up too?


                  Thanks guys for the voltage drop info

                  Pile thanks for that online calculator!
                  If we are thinking the same thing, the inspector wants the 12/3 so he has a red and black hot wire. The third wire ( white ) is unused.
                  To all who contribute to this board.
                  My sincere thanks , Pete.

                  Pureox OA
                  Westinghouse 300 amp AC stick
                  Miller Syncrowave 250
                  Hexacon 250 watt solder iron

                  Comment


                  • #10
                    Originally posted by burninbriar View Post
                    If we are thinking the same thing, the inspector wants the 12/3 so he has a red and black hot wire. The third wire ( white ) is unused.
                    But wouldn’t it be red & black to power, white to the common bus bar, and green to the ground bus bar?

                    Comment


                    • #11
                      Originally posted by Pile Buck View Post
                      But wouldn’t it be red & black to power, white to the common bus bar, and green to the ground bus bar?
                      I hope I don't get in trouble here, I'm not an electrician so don't take my stuff to the bank.
                      120 and 240 both use two wires to complete the circuit and one wire for safety to trip a breaker in case of an electrical short. 120 uses one hot (black) and neutral (white) to complete the circuit and 240 uses two hots out of phase (black & red or any color but white or green) to complete the circuit. That just leaves the safety ground to deal with.
                      To all who contribute to this board.
                      My sincere thanks , Pete.

                      Pureox OA
                      Westinghouse 300 amp AC stick
                      Miller Syncrowave 250
                      Hexacon 250 watt solder iron

                      Comment


                      • #12
                        If the cable is 12/2 w/gnd you are allowed to identify the white conductor with a permanent marker or black tape to be used as phase conductor only if it part of a cable assembly IE: romex, MC cable BX etc!
                        If the wires are installed in conduit you are not allowed to do this, with the exception being the conductors are over #6 awg.
                        But as the others stated the inspector has jurisdiction over what the code says.
                        Bob Kraemer/Licensed Electrical Contractor

                        Miller 330 ABP
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                        Grinders, Belt Sander Etc!
                        And more hand tools than I know what to do with

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                        • #13
                          i would call the inspector and ask him if he will alow you to paint the white wire ? be it with permanent marker or paint, if he goes for it great if not best to just bite the bullet and get the wire he wants.
                          white wires are used as hots in switch loops all the time so it can be done it just depends on what the inspector wants to alow, if he starts feeling like you are on a power trip or he is losing controle he will be come a real pain, some of them just start out on power trips and then you are screwed.
                          thanks for the help
                          ......or..........
                          hope i helped
                          sigpic
                          feel free to shoot me an e-mail direct i have time to chat. james@newyorkmetalart.com
                          summer is here, plant a tree. if you don't have space or time to plant one sponsor some one else to plant one for you. a tree is an investment in our planet, help it out.
                          JAMES

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                          • #14
                            Originally posted by fun4now View Post
                            , if he starts feeling like you are on a power trip or he is losing controle he will be come a real pain, some of them just start out on power trips and then you are screwed.
                            LOL Diplomacy is the word for the day.
                            To all who contribute to this board.
                            My sincere thanks , Pete.

                            Pureox OA
                            Westinghouse 300 amp AC stick
                            Miller Syncrowave 250
                            Hexacon 250 watt solder iron

                            Comment


                            • #15
                              Originally posted by fun4now View Post
                              some of them just start out on power trips and then you are screwed.
                              ain't that the truth... one of the state inspectors here forced the electricians to completely rewire a ticket booth across the driveway from a building we were putting up at a local HS. the pisser is that the ticket booth had NOTHING to do with our work, no power for it came from our building. the guy was famous for that kind of ****. grrr.
                              Bobcat 225NT
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