Announcement

Announcement Module
Collapse

How To Post Images

Want to know the how to upload images to your posts? Image Posting Tutorial
See more
See less

THHN Wire for retrofit ground

Page Title Module
Move Remove Collapse
X
Conversation Detail Module
Collapse
  • Filter
  • Time
  • Show
Clear All
new posts

  • THHN Wire for retrofit ground

    Gentlemen,

    In order to meet the stringent requirements of a prominent telecomm company to install fiber optic cable at my house, I will need to ground the antiquated circuit in my master bedroom. Everything is currently GFCI protected and the outlet that will feed the TV and cable box is at the end of an old run of #14 2-wire hooked up to a 15A breaker. Is there any reason that I could not simply fish a length of #14 green-jacketed THHN (bought a spool a long time ago and it looks like I will never run out) down the wall to that outlet and connect the other end in a nearby junction box? The JB is on a new, grounded circuit.

  • #2
    Re: THHN Wire for retrofit ground

    You have to make sure your service is properly grounded first. Otherwise bonding one piece of metal to another will accomplish nothing.

    Comment


    • #3
      Re: THHN Wire for retrofit ground

      Originally posted by tailgunner View Post
      You have to make sure your service is properly grounded first. Otherwise bonding one piece of metal to another will accomplish nothing.
      The house service was upgraded to 200A around 1990 and a number of circuits were added at the same time. The old, 2-wire circuits were left alone but the JB I would run the ground to is proper.

      Comment


      • #4
        Re: THHN Wire for retrofit ground

        Well, to be perfectly honest, I am NOT going to go ahead and say it's right to do so. What you are doing is running a "bootleg" approach. It will work in theory for that one single outlet on that circuit. However, from a troubleshooting perspective, it will raise ALOT of questions should something else go wrong on that circuit, like "Well, this is bootlegged, what else has been done to this circuit?". Granted all you wish to do is pick up a ground, but I pray you understand where I am going with this.

        However. One thing I have done for my parents is this.: Feed a single outlet in the living room to power their entertainment center. Not only did this take a sizeable load off the very old BX fed circuit, but picked a good ground for the sensitive electronics, AND they have a $30 surge protector to protect the entire setup. I will at least suggest you hire up an electrician to do the same?
        Last edited by tailgunner; 11-29-2009, 09:02 AM.

        Comment


        • #5
          Re: THHN Wire for retrofit ground

          pull a dedicated circuit like gunner did. your electronics will thank you. breid......

          Comment


          • #6
            Re: THHN Wire for retrofit ground

            Originally posted by tailgunner View Post
            Well, to be perfectly honest, I am NOT going to go ahead and say it's right to do so. What you are doing is running a "bootleg" approach. It will work in theory for that one single outlet on that circuit. However, from a troubleshooting perspective, it will raise ALOT of questions should something else go wrong on that circuit, like "Well, this is bootlegged, what else has been done to this circuit?".
            Would you still say that it is bootlegged if he ran the retrofit ground all the way back to the panel?

            Comment


            • #7
              Re: THHN Wire for retrofit ground

              Originally posted by cpw View Post
              Would you still say that it is bootlegged if he ran the retrofit ground all the way back to the panel?
              Yes.

              Also, if one were to go through the trouble of running a wire back to the panel, might as well just run a new circuit.

              Comment


              • #8
                Re: THHN Wire for retrofit ground

                How about driving a ground rod and running a wire from it to the ground screw on an isolated ground receptacle? I know this is rather insane, but he would have good grounding.

                For what it's worth because of SAFETY issues, please hire a good electrician and get the job done the right way.

                Comment


                • #9
                  Re: THHN Wire for retrofit ground

                  Originally posted by Woussko View Post
                  How about driving a ground rod and running a wire from it to the ground screw on an isolated ground receptacle? I know this is rather insane, but he would have good grounding.
                  Except that isolated ground rod likely has a different potential than the original ground rod.

                  Comment


                  • #10
                    Re: THHN Wire for retrofit ground

                    Originally posted by tailgunner View Post
                    Well, to be perfectly honest, I am NOT going to go ahead and say it's right to do so. What you are doing is running a "bootleg" approach. It will work in theory for that one single outlet on that circuit. However, from a troubleshooting perspective, it will raise ALOT of questions should something else go wrong on that circuit, like "Well, this is bootlegged, what else has been done to this circuit?". Granted all you wish to do is pick up a ground, but I pray you understand where I am going with this.

                    However. One thing I have done for my parents is this.: Feed a single outlet in the living room to power their entertainment center. Not only did this take a sizeable load off the very old BX fed circuit, but picked a good ground for the sensitive electronics, AND they have a $30 surge protector to protect the entire setup. I will at least suggest you hire up an electrician to do the same?
                    I actually ran a dedicated circuit to the "real" entertainment center in the den. This room will have a little TV and a secondary DVR/box. I hear you about "bootlegging" and I'm sure I know exactly where you are going with that. Point taken.

                    Woussko - The house has good, grounded power run to the kitchen, bathrooms, some of the garage outlets and a portion of the living space but the bedrooms were ignored when the system was upgraded.

                    At some point I will either pull a new line or hire it out, but the cable installation team will be here Dec. 2 and I needed that outlet to read "correct" on a circuit tester. Hey, I could have run a jumper from the grounding screw to the neutral rather than bond it to the ground bus, right?

                    Comment


                    • #11
                      Re: THHN Wire for retrofit ground

                      {Hey, I could have run a jumper from the grounding screw to the neutral rather than bond it to the ground bus, right?}


                      Actually, no. The only place and the only time they are connected is in the main breaker box. And then all grounds are on the ground bar and all neutrals must be placed on the neutral bar. Never the two shall meet anywhere else in the circuit. And with a sub panel, the two bars are isolated from each other. Remember that a neutral is a current carrying conductor. The ground is not a current carrying conductor, it is a ground only. That is why is can be a size smaller than the current carrying conductors in that particular circuit.
                      Hope that helps.
                      Cheers,
                      Jim Don

                      Comment


                      • #12
                        Re: THHN Wire for retrofit ground

                        Originally posted by JimDon View Post
                        {Hey, I could have run a jumper from the grounding screw to the neutral rather than bond it to the ground bus, right?}


                        Actually, no. The only place and the only time they are connected is in the main breaker box. And then all grounds are on the ground bar and all neutrals must be placed on the neutral bar. Never the two shall meet anywhere else in the circuit. And with a sub panel, the two bars are isolated from each other. Remember that a neutral is a current carrying conductor. The ground is not a current carrying conductor, it is a ground only. That is why is can be a size smaller than the current carrying conductors in that particular circuit.
                        Hope that helps.
                        Cheers,
                        Jim Don
                        I was kinda' joking about that. As in "hey, instead of bootlegging a functioning ground I could have bootlegged something potentially dangerous"

                        Comment


                        • #13
                          Re: THHN Wire for retrofit ground

                          Sorry,
                          Wasn't meant to step on you or anything. The nuance doesn't always come through when one reads something. It's not like the spoken word and seeing a person's facial expression.
                          Either way, it's a good reminder for those who don't know the ins and outs of the correct way of grounding and bonding that a person shouldn't do that.
                          Cheers,
                          Jim Don

                          Comment


                          • #14
                            Re: THHN Wire for retrofit ground

                            Originally posted by JimDon View Post
                            Sorry,
                            Wasn't meant to step on you or anything. The nuance doesn't always come through when one reads something. It's not like the spoken word and seeing a person's facial expression.
                            Either way, it's a good reminder for those who don't know the ins and outs of the correct way of grounding and bonding that a person shouldn't do that.
                            Cheers,
                            Jim Don
                            That brings up a question...

                            Lets say an old kitchen has been gutted down to the studs. The wiring is predominantly 2-wire ungrounded but at some point in the past a dedicated and properly grounded circuit was run for the refrigerator. Rather than pull all new Romex for the kitchen, an electrician tears out all of the branch wiring but leaves the original wire as a feed for a junction box (still with me?) and re-wires those branches from the junction box with 12-2 Romex. He also installs a junction box in-line to the refrigerator and bonds the ground of the newly wired branches to the ground on the refrigerator circuit with a scrap of green-sheathed #12 from MC (JB's are a single studspace apart and accessible from inside a cabinet). This gets a pass on the wallcover inspection, so I assume there isn't any specific code prohibition.

                            Is that kosher?

                            Comment

                            Working...
                            X