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  • panel wiring

    I have inherited an unfinished garage sub panel installation. It is ran to an attached garage 50' from the main house panel. A 100 amp double pole feeds triple 2 Al to a QO sub. The neutral is not bonded at the sub. One wire with a red stripe is on what looks like the hot. The other wire is on the opposite lug. The bare is on what looks like the neutral lug. There is a ground bus screwed in the panel as well with nothing on it. The feeder wire is only three wires. What should be the next step, starting over or finishing a pretty good idea. The house has 200 amp service in a Cutler panel. Both insulated wires are on the feed breaker and the bare is on the ground bus in the main panel. Any info is appreciated.

  • #2
    Re: panel wiring

    If the area is under the 2008 electric code, then you need to start over and install 4 wires to the garage.
    You also need to install 2 ground rods.
    If the area requires a license to do electrical work, I would turn this over to an electrician.

    Comment


    • #3
      Re: panel wiring

      Originally posted by jbfan View Post
      You also need to install 2 ground rods.
      2 ground rods for a 100 amp sub panel?

      To original poster call a electrican.
      Last edited by swoosh81; 09-07-2009, 07:40 PM.

      Comment


      • #4
        Re: panel wiring

        Originally posted by swoosh81 View Post
        2 ground rods for a 100 amp sub panel?
        According to the 2008 code, you bet. Any sub panel to a detached structure as a matter of fact.

        Comment


        • #5
          Re: panel wiring

          May have to get someone who knows what theyre doing. Its been a head scratcher wondering what to do and why its the way it is. Im giving points for effort though. As far as I know no juice has been thrown to it (thankfully). The house was built in the mid 80s. No electric problems thus far everything else seems to be good. All except this sub installation. The more I think about the potential i do want to pursue finishing what was started, as correctly as possible.

          Comment


          • #6
            Re: panel wiring

            Originally posted by killavolt View Post
            According to the 2008 code, you bet. Any sub panel to a detached structure as a matter of fact.
            Does no one do a resistance to ground test anymore before pounding in a second and normally uncalled for rod? Does anyone even know what megger test equipment is?

            Comment


            • #7
              Re: panel wiring

              Originally posted by bwent View Post
              I have inherited an unfinished garage sub panel installation. It is ran to an attached garage 50' from the main house panel. A 100 amp double pole feeds triple 2 Al to a QO sub. The neutral is not bonded at the sub. One wire with a red stripe is on what looks like the hot. The other wire is on the opposite lug. The bare is on what looks like the neutral lug. There is a ground bus screwed in the panel as well with nothing on it. The feeder wire is only three wires. What should be the next step, starting over or finishing a pretty good idea. The house has 200 amp service in a Cutler panel. Both insulated wires are on the feed breaker and the bare is on the ground bus in the main panel. Any info is appreciated.
              Call an electritian, because you do not know what you have or what to do with it.
              info for all: http://www.hoistman.com http://www.freeyabb.com/phpbb/index....wwtoolinfoforu --- "I like long walks, especially when they are taken by people who annoy me."

              Comment


              • #8
                Re: panel wiring

                Come on guys, the OP said it is an attached garage so what's with the ground rods? OP, first off, What type of wire feeds this panel? Is it armored BX type cable? If so you do not need to change the wire. If it is some kind of wire without a bond then you need something to make a bond. I have not seen wire without a bond in many years. If you have 4 wires black, red, white, and a bond you are OK. If you have 3 wires in a metal jacket, you are OK. I assume since you have 3 wires you have armored cable. If that is the case connect black and red wires to the main lugs in the subpanel. Connect the white wire to the nuetral lug. REMOVE OR DO NOT USE THE BONDING SCREW. Be sure you have a good connector on the entrace cable to the metal box and its secure. When wiring into the panel (if you use Romex) put the bonds on the grounding (bonding) bar and not the nuetral bad. You said the panel had a seperate bonding bar. That's it

                Comment


                • #9
                  Re: panel wiring

                  Originally posted by swoosh81 View Post
                  Does no one do a resistance to ground test anymore before pounding in a second and normally uncalled for rod? Does anyone even know what megger test equipment is?
                  Nope. I guess you are the only one.


                  Do you have the $1200 tester required to do ground rod resistance? I don't, but at the same time I rarely get asked about the resistance or a second rod.
                  For those who get asked and are required to show resistance numbers a second rod is just easier.

                  I personally don't stress over a second rod because they don't do very much to begin with.

                  Also, if you are doing ground rod resistance with a megger you are doing it wrong anyway.

                  Comment


                  • #10
                    Re: panel wiring

                    Originally posted by QROKING View Post
                    Come on guys, the OP said it is an attached garage so what's with the ground rods?
                    Originally posted by bwent View Post
                    I have inherited an unfinished garage sub panel installation. It is ran to an attached garage 50' from the main house panel.
                    Oops! I may have misread the OP's post. At first, it looked like he was completing a sub panel installation from an unfinished garage to an attached garage. I assumed two different structures. If he is doing as QROKING suggests, i.e. completing an unfinished sub panel in an attached garage then QROKING is correct. If the OP had said "I have inherited an unfinished sub panel in an attached garage", his statement would have been clearer. Sorry if I misinformed anyone.

                    Comment


                    • #11
                      Re: panel wiring

                      Originally posted by Speedy Petey View Post
                      Nope. I guess you are the only one.


                      Do you have the $1200 tester required to do ground rod resistance? I don't, but at the same time I rarely get asked about the resistance or a second rod.
                      For those who get asked and are required to show resistance numbers a second rod is just easier.

                      I personally don't stress over a second rod because they don't do very much to begin with.

                      Also, if you are doing ground rod resistance with a megger you are doing it wrong anyway.
                      That is assuming the second rod is gonna give you 25 ohms of resistance. A side note Megger is the brand name, although most guys just call it megger test equipment when there's actually all different products they make.

                      Comment


                      • #12
                        Re: panel wiring

                        Originally posted by swoosh81 View Post
                        That is assuming the second rod is gonna give you 25 ohms of resistance.
                        Then I suggest you go back and read this section of the code. The 25 ohms is a non-issue once you sink the second rod. With two rods the 25 ohm requirement goes out the window.




                        Originally posted by swoosh81 View Post
                        A side note Megger is the brand name, although most guys just call it megger test equipment when there's actually all different products they make.
                        Ummm...yeah. I know.

                        My "megger" is made by Amprobe.

                        Comment


                        • #13
                          Re: panel wiring

                          Thanks for the verbal schematic QROKING. The feeder is Al triple 2 with two insulated and one bare wrapped around the others. I twisted the bare together to get the third wire. I mounted the box in the wall and fed the wire through. It was just sitting in the hole they cut. The wire appears to be service wire. The grounding bar was laying in the box and i screwed it into the box. All wires that will go in it will be Romex. This wouldve been easier with a 4 wire feeder, but i cant complain. The box will only power lights, outlets and an opener. It looks like it will work, from information i have gathered it looks like it will. I will go ahead and put a ground rod in. Does it have to be a certain distance or place? Is it the bare 8 Cu? The green bonding screw is missing after the last cleaning anyway good thing i wont need it. thanks

                          Comment


                          • #14
                            Re: panel wiring

                            The way I read this original post your plan is all wrong. IF this is an attached garage as it seems then you CANNOT use the 3-wire feeder as you suggest, and NO ground rod is needed or wanted.

                            For a sub-panel in an attached garage or other area a 4-wire feeder is MANDATORY.

                            Can you please clarify that it is either a detached garage or attached?

                            Comment


                            • #15
                              Re: panel wiring

                              To hell with a second ground rod, go full-bore and install a grounding ring around the facility, and "cad-weld" the number 4 copper to each ground rod and joint. Then take a picture of the inspector's face when he shows up on the job. Your work will never be questioned again!

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