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alexkharden
Grounding Electrode question

Hey everyone, long time listener, first time caller:D I'm hoping someone can help me out with this dilemma if that is, in fact, what it is.

I've been wading through the NEC, but I just can't seem to nail down the answer to this question. My wife and bought our house a year ago, and I've been slowly untangling the mess that is our electrical system. Now I'm trying to correctly ground the system.

The problem is, I have no access to the water pipe coming in to the basement. There's about four inches of exposed pipe, but that section has been completely covered by an epoxy compound to fix a leak, so there's nowhere to connect a ground wire.

Currently I have a 10' Cu grounding rod driven into the ground outside with #6 connecting to the breaker panel. I know that alone will probably not meet the max 25 ohm resistance requirement, but will adding another ground rod, 6' away, and bonding the two rods with #6 be sufficient to make an inspector happy and keep my family safe?

Or is the fact that my system is not grounded to the water pipe a very bad thing?

Thanks everyone for your help!

HoustonRemodeler
Re: Grounding Electrode question

I'm not an electrician and I didn't sleep at a Holiday Inn, but I do know we stopped grounding to the plumbing systems years ago. Its all grounding rods now.

dj1
Re: Grounding Electrode question

I agree with HR about the rod, not the hotel.

alexkharden
Re: Grounding Electrode question

Well, unless I'm misreading it, the NEC still requires grounding to the cold water pipe. That's why the question, since it appears to require it. The caveat of "if present" is there, but that's where my dilemma comes in because the pipe is technically present, but unable to be used.

So, does that then mean the two grounding rods would be sufficient? And would #6 be fine to bond the two rods?

Also, the two rods need to be bonded together, but do both rods have to be bonded to the panel as well? I don't think I've ever seen that done, but the reading got me twisted up in my thinking, so I don't know what's up or down anymore.

Thanks!

Brad
Re: Grounding Electrode question

Drive a second rod at least 6' from the existing one. Make sure there is no gas, electric, cable, water, sewer, etc. at the new rod location. Connect the two rods using #6 copper and two acorn clamps. An additional conductor to the panel is not necessary.

If at all possible a connection should be made to the incoming water line. #4 copper for a 200 amp service, #6 copper for a 100 amp service.

See www.mikeholt.com click on the free graphics in the left hand column, click on grounding versus bonding graphics, click on grounding electrode conductor terminating.

Fencepost
Re: Grounding Electrode question

If the pipe is unable to be used, then don't use it.

As for the grounding electrodes, code requires there be NO CONNECTIONS in the conductor between the panel and the electrodes. This gives you two options:

  • One wire from the panel to the first electrode, passing through the acorn clamp WITHOUT A BREAK and on to the acorn clamp on the second ground rod; or
  • Two wires from the panel, one to each ground rod.

You can't add a grounding electrode and just connect it to the existing one, because that would constitute a connection in the grounding conductor.

Brad
Re: Grounding Electrode question
Fencepost wrote:

If the pipe is unable to be used, then don't use it.

As for the grounding electrodes, code requires there be NO CONNECTIONS in the conductor between the panel and the electrodes. This gives you two options:

  • One wire from the panel to the first electrode, passing through the acorn clamp WITHOUT A BREAK and on to the acorn clamp on the second ground rod; or
  • Two wires from the panel, one to each ground rod.

You can't add a grounding electrode and just connect it to the existing one, because that would constitute a connection in the grounding conductor.

That is totally false. See post #5.

Fencepost
Re: Grounding Electrode question
brrichter wrote:

That is totally false. See post #5.

Inspector's interpretation. Around here they don't allow a jumper from rod to rod; they would consider the two acorn clamps on the first rod a splice.

Brad
Re: Grounding Electrode question
Fencepost wrote:

Inspector's interpretation. Around here they don't allow a jumper from rod to rod; they would consider the two acorn clamps on the first rod a splice.

Sorry your people are misinformed. Got to keep the inspectors happy. As a matter of fact, I always install a continuous conductor, but it's not required. Saves the cost of an additional acorn.

alexkharden
Re: Grounding Electrode question

Thank you very much everyone:)

According to the graphic, it's fine to use two acorn clamps, but I do see how running a continuous line could be beneficial and possibly even lower the resistance a bit, not to mention that, since I'm running a new ground line in it's entirety, one way is just as easy to do as another.

I noticed in the picture the bonding wire between the two electrodes was buried. Any requirement on the burial depth? NEC requirement anyway, I know my local ordinance could be different.

Unfortunately, the water line is a no go. the four inches or so of pipe that used to be exposed is covered by that epoxy. I don't know how good of a ground it would be anyway. When I moved in the entire main water line was corroded through. The plumbers ran a PEX insert down through the old line to the meter, so the old iron pipe isn't even in use anymore. Just abandoned to finish corroding away.

Edit: Spelling

Brad
Re: Grounding Electrode question
alexkharden wrote:

Thank you very much everyone:)

According to the graphic, it's fine to use two acorn clamps, but I do see how running a continuous line could be beneficial and possibly even lower the resistance a bit, not to mention that, since I'm running a new ground line in it's entirety, one way is just as easy to do as another.

I noticed in the picture the bonding wire between the two electrodes was buried. Any requirement on the burial depth? NEC requirement anyway, I know my local ordinance could be different.

Unfortunately, the water line is a no go. the four inches or so of pipe that used to be exposed is covered by that epoxy. I don't know how good of a ground it would be anyway. When I moved in the entire main water line was corroded through. The plumbers ran a PEX insert down through the old line to the meter, so the old iron pipe isn't even in use anymore. Just abandoned to finish corroding away.

Edit: Spelling

Burial is not required, however an 8' ground rod should have 8' of contact with the earth. Also keeps the rods and conductors from becoming a trip hazard.

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