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Removal of 3-wire branch circuits with new service?

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    Removal of 3-wire branch circuits with new service?

    Hey Guys, been lurking around the forums for a while, found some great content which I appreciate. So thanks a bunch. I was hoping I could get some feed back or some help on a situation I was just in.

    My boss and I did a new resi service and panel change out on a house built in the 70s. The existing setup had the first means of disconnect at the panel inside, but my boss (not thinking about it too much) bought a meter pack with a main breaker. So naturally I separated the grounds and neutrals inside when doing the panel up. But the inspector tried nailing us on re-using old 3-wire BCs for the range and dryer. It was stated that we couldn't go from a 3-wire to 4-wire back to a 3-wire (service conductors -> feeder to main panel -> branch circuits for range/dyer.) My boss said he overlooked that and should have known better, but I've never heard of a code article requiring the separation of such. Any ideas where I can find such a reference in NEC 2014? Or is he dead wrong. A tough pill to swallow being that the customers are already paying for a new service.

    #2
    Take a look at (3).

    Welcome to the forum.

    250.140 Frames of Ranges and Clothes Dryers. Frames
    of electric ranges, wall-mounted ovens, counter-mounted
    cooking units, clothes dryers, and outlet or junction boxes
    that are part of the circuit for these appliances shall be
    connected to the equipment grounding conductor in the
    manner specified by 250.134 or 250.138.
    Exception: For existing branch-circuit installations only
    where an equipment grounding conductor is not present in
    the outlet or junction box, the frames of electric ranges,
    wall-mounted ovens, counter-mounted cooking units,
    clothes dryers, and outlet or junction boxes that are part of
    the circuit for these appliances shall be permitted to be
    connected to the grounded circuit conductor if all the fol-
    lowing conditions are met.
    (1) The supply circuit is 120/240-volt, single-phase, 3-wire;
    or 208Y/120-volt derived from a 3-phase, 4-wire, wye-
    connected system.
    (2) The grounded conductor is not smaller than 10 AWG
    copper or 8 AWG aluminum.
    (3) The grounded conductor is insulated, or the grounded
    conductor is uninsulated and part of a Type SE service-
    entrance cable and the branch circuit originates at the
    service equipment.

    (4) Grounding contacts of receptacles furnished as part of
    the equipment are bonded to the equipment.
    Rob

    Moderator

    All responses based on the 2017 NEC unless otherwise noted

    Comment


      #3
      It depends if those neutrals are insulated or not. If they are bare (SEU) it must come out of the service, if its bare copper (NM) not code since day one, but if the neutral is insulated it may originate from a sub panel.

      Comment


        #4
        Originally posted by infinity View Post
        Take a look at (3).

        Welcome to the forum.
        Thanks guys. That makes sense know that I think it through from a practical bonding point of view. I did a quick (and I mean quick) search on google about this but didn't get much. Wonder how often this isn't done when others were put in my scenario. Oh well. I want to be one of the good ones, hate breaking the code and always looking to improve, so you can bet I'll never forget this one.

        Comment


          #5
          Originally posted by ArcLazerbeam View Post
          Thanks guys. That makes sense know that I think it through from a practical bonding point of view. I did a quick (and I mean quick) search on google about this but didn't get much. Wonder how often this isn't done when others were put in my scenario. Oh well. I want to be one of the good ones, hate breaking the code and always looking to improve, so you can bet I'll never forget this one.
          If the conductors have an insulated neutral then you don't need to change anything as they can come from a subpanel per the exception. But if they are SE cable with bare neutral then you would have to change to a 4-wire.
          [COLOR=navy]If you aim at nothing, you will hit it every time![/COLOR]

          Comment


            #6
            Originally posted by Little Bill View Post
            If the conductors have an insulated neutral then you don't need to change anything as they can come from a subpanel per the exception. But if they are SE cable with bare neutral then you would have to change to a 4-wire.
            To be clear- if the cable has an insulated neutral and a ground such as 10/3 or 6/3 NM.

            -Hal

            Comment


              #7
              Originally posted by ArcLazerbeam View Post
              Hey Guys, been lurking around the forums for a while, found some great content which I appreciate. So thanks a bunch. I was hoping I could get some feed back or some help on a situation I was just in.

              My boss and I did a new resi service and panel change out on a house built in the 70s. The existing setup had the first means of disconnect at the panel inside, but my boss (not thinking about it too much) bought a meter pack with a main breaker. So naturally I separated the grounds and neutrals inside when doing the panel up. But the inspector tried nailing us on re-using old 3-wire BCs for the range and dryer. It was stated that we couldn't go from a 3-wire to 4-wire back to a 3-wire (service conductors -> feeder to main panel -> branch circuits for range/dyer.) My boss said he overlooked that and should have known better, but I've never heard of a code article requiring the separation of such. Any ideas where I can find such a reference in NEC 2014? Or is he dead wrong. A tough pill to swallow being that the customers are already paying for a new service.
              Here, if they are not moved, they can stay. Move em (even shortening the original wire run) and you get to pull all new 4 wire circuits.
              Electricians do it until it Hertz!

              Comment


                #8
                Originally posted by hbiss View Post
                To be clear- if the cable has an insulated neutral and a ground such as 10/3 or 6/3 NM.

                -Hal
                We're talking about existing 3-wire circuits to a stove or dryer. The exception allows the neutral to also be the EGC. But if the 3-wire has a bare neutral from a SE cable then it would have to originate from the main panel and not from a subpanel.
                [COLOR=navy]If you aim at nothing, you will hit it every time![/COLOR]

                Comment

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