Grounding Question

Old 01-15-04, 06:58 PM
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Grounding Question

My electrical system is grounded to my copper plumbing system. I am getting a new water line installed and abandoning the old one. The contractor is going to run copper 2' outside my house. Will this be sufficient to ground my system? Do I need to run a jumper from my new line to my old to be sure? Please help ASAP.
Old 01-15-04, 07:23 PM
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This new water pipe will not be sufficient to ground your system. To use the incoming water pipe as part of the grounding requires a minimum of ten feet of copper in the ground. If you can talk him into ten feet of copper you will be all set.

However, the existing water pipe entering the house may still be useable. If it remains in the ground outside the house, and still enters the house just leave it connected.

Keep in mind that regardless of whether your water pipes are used as part of the grounding system, they must still be connected to your electrical system ground. So the answer to part of your question is yes, make sure that the existing interior water pipes are hooked up in some manner.

Do you have any other means of grounding? The code now requires at least two means of grounding. In addition to the water pipes, you must use something else, such as a ground rod inserted into the ground.

If your new water pipes are not useable as a ground, then you will have to add something.
Old 01-16-04, 04:07 AM
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Great! Thanks for your help. Let me ask you this. I have alot of problems with my lights flickering and dimming, could this be due to inadequit grounding? I am pretty sure that my existing copper pipe does not run 10 feet out.

Also, I don't need to hook up a temporary ground while I am switching over to the new pipe do I? In otherwords, when he cuts the pipe my system will be without a ground for a few hours. Is that ok?
Old 01-16-04, 07:35 AM
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There are many possible causes for lights flickering, but poor grounding is not usually one of them. If you search this forum for the word "flicker" or "dimming", you'll find lots of discussion on the subject.

The panel grounding is primarily for lightning protection. As long as you don't do this work during an electrical storm, you can probably do without system grounding for a few hours.
Old 01-16-04, 10:19 AM
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As racraft has pointed out, the NEC requires "supplementary" Grounding Electrodes.

Possibly you could drive 2 Ground Rods in the bottom of the trench you'r excavating for the new water-service line. The deeper the Grounding Rods are set in the soil, the better the Ground. Drive the 2 Rods at least 10 ft. apart, and use bare #4 copper wire for the Grounding Electrode Conductor.

If necessary, skim the insulation off an insulated #4 wire because the bare copper exposed to the soil will result a better Ground.The Grounding Electrode Conductor should extend from the Neutral terminal bar in the Service to all Grounding Electrode connections as one continual conductor without any breaks in the Conductor.

Good Luck and Enjoy the Experience!!!!!!!!!!!

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