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What type of wire for 0-10 dimming installation explained better

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    What type of wire for 0-10 dimming installation explained better

    Hi everyone.

    I recently posted a similar question, thought I would explain my question better. I am wiring a residential large shop, so open ceilings and romex for power. I was going to use a Lutron 0-10 dimmer / switch combo so the 0-10 wire will need to be rated to be installed in an switch box that will have 240v in it. 240v only because I will have two separate circuits feeding multiple rows of lights. What kind of wire would be the best for this installation? I am running yellow 12-2 for everything power so I thought I would run white 14-2 for 0-10. Would 14-2 romex be acceptable to be ran in a switch box?

    #2
    I try not to endorse a brand or specific product, but sometimes the others haven't caught up yet. This cable assembly is what I've seen in commercial 0-10v dimming installations:

    http://mcpcsduo.southwire.com/

    The lighting controllers were in panels specific to the product, so I didn't have to worry about insulation ratings/barriers/conductor spacing issues that you would have to be addressed in a wallbox.

    Comment


      #3
      14 guage Romex is fine but it's overkill and you don't need the egc. You should be able to get 16 or 18 guage control cable, most likely in the standard purple and grey at your supply house.
      If Billy Idol is on your playlist go reevaluate your life.

      Comment


        #4
        Originally posted by ActionDave View Post
        14 guage Romex is fine but it's overkill and you don't need the egc. You should be able to get 16 or 18 guage control cable, most likely in the standard purple and grey at your supply house.
        Thanks for the reply ActionDave, are most rated to be installed in class 1 installations? If I ask my supply house guys I am sure they would look at me cross eyed?

        Comment


          #5
          I don't believe nm cable is compliant as it is not rated class II but rather class I, as I understand it. If you use chapter 3 wiring method then the entire install must be a chapter 3 install. Sometimes that could work with 0-10v dimming....
          They say I shot a man named Gray and took his wife to Italy
          She inherited a million bucks and when she died it came to me
          I can't help it if I'm lucky

          Comment


            #6
            There is no restriction on using NM or any other Chapter 3 wiring method for a Class 2 or 3 circuit. You could use 5kV cable if you wanted too....of course that might be a bit costly.
            Don, Illinois
            (All code citations are 2017 unless otherwise noted)

            Comment


              #7
              You don't seem to understand that your 0-10V control cable doesn't have to be listed for 120 or 240V. The fixtures and switches will provide the necessary separation between the CL2 wiring and the power.

              The only problem comes in when you want to run the control wiring with the power in the same cable or raceway. But you aren't doing that.

              -Hal

              Comment


                #8
                Originally posted by Dennis Alwon View Post
                I don't believe nm cable is compliant as it is not rated class II but rather class I, as I understand it. If you use chapter 3 wiring method then the entire install must be a chapter 3 install. Sometimes that could work with 0-10v dimming....
                My understanding is that you can use Chapter 3 methods without restriction on what you may use for other parts of the Class 2 or 3 circuit.
                On the other hand if you need to reclassify the circuit as Class 1 for any reason (such as sharing a raceway with power) you must treat the entire circuit as Class 1 and use exclusively Chapter 3 methods.

                Comment


                  #9
                  I believe you are correct.

                  -Hal

                  Comment


                    #10
                    Originally posted by GoldDigger View Post

                    My understanding is that you can use Chapter 3 methods without restriction on what you may use for other parts of the Class 2 or 3 circuit.
                    On the other hand if you need to reclassify the circuit as Class 1 for any reason (such as sharing a raceway with power) you must treat the entire circuit as Class 1 and use exclusively Chapter 3 methods.
                    Aren't you changing the circuit to class 1 by using chapter 3 wiring? Not sure how you can change the circuit to class 1 when a class 2 trany is involved. I know that class 3 wiring is rated for class 2 but class 2 cannot be used in class 3. I assumed that class 1 would have the same restriction
                    They say I shot a man named Gray and took his wife to Italy
                    She inherited a million bucks and when she died it came to me
                    I can't help it if I'm lucky

                    Comment


                      #11
                      Originally posted by Dennis Alwon View Post

                      Aren't you changing the circuit to class 1 by using chapter 3 wiring?
                      I've never heard that before. The wiring method does not determine the circuit class AFAIK, I always thought the equipment determined the class which determined the wiring method requirements. I was also under the impression that you could use a class 1 wiring method for a class 2 circuit w/out modifications of ... anything.

                      But, ... You Dennis are way more savvy than I.

                      Comment


                        #12
                        Originally posted by oldsparky52 View Post
                        I've never heard that before. The wiring method does not determine the circuit class AFAIK, I always thought the equipment determined the class which determined the wiring method requirements. I was also under the impression that you could use a class 1 wiring method for a class 2 circuit w/out modifications of ... anything.
                        Again, correct!

                        Originally posted by Dennis Alwon
                        Aren't you changing the circuit to class 1 by using chapter 3 wiring? Not sure how you can change the circuit to class 1 when a class 2 trany is involved. I know that class 3 wiring is rated for class 2 but class 2 cannot be used in class 3. I assumed that class 1 would have the same restriction
                        That would only happen if you reclassify in order to run the CL2 wiring with the power or Class 1 conductors. If you used 14/2 NM for a thermostat it's still a CL2 circuit.

                        Not sure how you can change the circuit to class 1 when a class 2 trany is involved.
                        Sharpie!

                        -Hal



                        Comment


                          #13
                          When I read art 411 I see this and #3 says wiring methods of Chapter 3. I cannot run nm cable and not terminate in a box if I use chapter 3 methods... This is why I am confused by the comments above

                          411.6(D) Insulated Conductors. Insulated secondary circuit
                          conductors shall be of the type, and installed as, described in
                          (1), (2), or (3):
                          (1) Class 2 cable supplied by a Class 2 power source and
                          installed in accordance with Parts I and III of Article 725.
                          (2) Conductors, cord, or cable of the listed system and installed
                          not less than 2.1 m (7 ft) above the finished floor
                          unless the system is specifically listed for a lower installation
                          height.
                          (3) Wiring methods described in Chapter 3.
                          They say I shot a man named Gray and took his wife to Italy
                          She inherited a million bucks and when she died it came to me
                          I can't help it if I'm lucky

                          Comment


                            #14
                            Originally posted by Dennis Alwon View Post
                            When I read art 411 I see this and #3 says wiring methods of Chapter 3. I cannot run nm cable and not terminate in a box if I use chapter 3 methods... This is why I am confused by the comments above
                            Now I'm confused, why can't you use nm (for the class 2 or 3 circuits) and make the class 2 or 3 connections in a box? I'm assuming the box will not have class 1 wiring.

                            I re read Dennis's post and I see I misunderstood, but still, why can't you use nm and not terminate in a box?
                            Last edited by oldsparky52; 09-11-19, 08:19 PM.

                            Comment


                              #15
                              Art 411 only relates to low voltage lighting systems operating at 30 volts or less. The language seems to indicate that CL2 conductors need to be run as a Chapter 3 wiring method if you don't use a CL2 cable. What they are actually saying is that for systems larger than CL2, Chapter 3 wiring methods are required.

                              -Hal

                              Comment

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