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  • #16
    use 3/4" EMT [CONDUIT]. using smaller pipe you will need to derate ampacity of the wire. down sizing the wire to save room in the conduit should be avoided. the correct size grounding conductor for a 30 amp circuit is #10 copper. applying these NEC guidelines your install will be to code.
    dave.



    IBEW electrican 26 yrs
    Last edited by rvpc; 11-13-2009, 09:06 PM. Reason: forgot a sentence
    IBEW electrican 26 yrs

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    • #17
      Originally posted by rvpc View Post
      use 3/4" EMT [CONDUIT]. using smaller pipe you will need to derate ampacity of the wire. down sizing the wire to save room in the conduit should be avoided. the correct size grounding conductor for a 30 amp circuit is #10 copper. applying these NEC guidelines your install will be to code.
      dave.



      IBEW electrican 26 yrs
      I was going to use the #10 for feeds & the #12 for grounds. So I should use all #10 wire? I was always told that the ground can be one size smaller than the feed.
      MM250
      Trailblazer 250g
      22a feeder
      Lincoln ac/dc 225
      Victor O/A
      MM200 black face
      Whitney 30 ton hydraulic punch
      Lown 1/8x 36" power roller
      Arco roto-phase model M
      Vectrax 7x12 band saw
      Miller spectrum 875
      30a spoolgun w/wc-24
      Syncrowave 250
      RCCS-14

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      • #18
        yes use all #10. per NEC table 250.122, Minimum Size Equipment Grounding Conductors for Grounding Raceway and Equipment:

        rating or setting of overcurrent
        device in circuit ahead of equipment
        not exceeding [amperes]
        15 grounding wire size #14
        20 grounding wire size #12
        30 grounding wire size #10
        40 Grounding wire size #10
        60 grounding wire size #10
        100 grounding wire size #8



        sorry i did not respond sooner today. pm me if you want. glad to help you.

        dave.
        Last edited by rvpc; 11-14-2009, 06:38 PM.
        IBEW electrican 26 yrs

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        • #19
          Thanks, all #10 it is. I am waiting for my disconnect to arrive & then I can run the conduit as I mount everything.
          MM250
          Trailblazer 250g
          22a feeder
          Lincoln ac/dc 225
          Victor O/A
          MM200 black face
          Whitney 30 ton hydraulic punch
          Lown 1/8x 36" power roller
          Arco roto-phase model M
          Vectrax 7x12 band saw
          Miller spectrum 875
          30a spoolgun w/wc-24
          Syncrowave 250
          RCCS-14

          Comment


          • #20
            Conduit Size

            I looked up the NEC (National Electric Code) and they said that it will legally fit into 1/2" EMT, but it will be a fairly hard pull, especially if you have any bends in your run, so I would recommend a 3/4" EMT for your wiring. PVC would be a poor choice becuase it cracks easier (not good in a shop) and it also has a tendencey to sag and look like crap. Also, you local Menards or whatever should sell wire pulling lubricant, it it might be a good idea to get a bottle of that. Good luck!

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            • #21
              Originally posted by rvpc View Post
              use 3/4" EMT [CONDUIT]. using smaller pipe you will need to derate ampacity of the wire. down sizing the wire to save room in the conduit should be avoided. the correct size grounding conductor for a 30 amp circuit is #10 copper. applying these NEC guidelines your install will be to code.
              dave.



              IBEW electrican 26 yrs
              NEC 358.60 Grounding. EMT shall be permitted as an equipment
              grounding conductor.
              A 20% derating applies regardless of what size conduit is used because the derating factor is dependent on the number of conductors, not the size of the conduit.

              See NEC 310.15 (2) (a)
              Last edited by Bodybagger; 11-22-2009, 12:39 AM. Reason: A 20%, not "An 20%"

              80% of failures are from 20% of causes
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