Electrical Wiring in the Home/Grounding

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Question
QUESTION: Hello,

Would installing a second grounding rod about 40 feet from another rod be too complicated to do? I have called a few places and one electrician, whose company is a ways off,  said I could do the work myself. The rod would be for satellite grounding, although I cannot say someone might use it for grounding something else in the future.

What material do I need for this project? Two of the guys I called said they would use a 6 foot rod, not the usual 8 foot. Does a second rod not need to be as long?

Thanks

ANSWER: According to the code a second rod must be at least 6' from the first one but does not indicate a maximum distance. The code states if one rod has at least a resistance of 25 ohms a second rod is not required, but the local inspectors require a second rod regardless. The local inspector can require more than the code so I would check with the local inspector to see what is recommended. I would prefer to install a second rod 6' from the original and just run a bare copper buried wire to the second location from this rod. Of course the second rod must be connected to the original and also to the panel via a bare ground conductor also. Thanks J

---------- FOLLOW-UP ----------

QUESTION: Hello,

I understand that the two rods must be connected by 6 awg, but what do you mean about the panel? We do have a grounding rod installed with a wire going up to the meter, but does the second rod have to have a wire going straight to the meter?

Here is what I was originally going by:
http://ecmweb.com/contractor/code-qa-2. I believe I found the picture originally on mikeholt.com, but for some reason IE did not save the page in my browsing history.

Someone had commented to me that they would use 4 awg, but everywhere else it says to use 6. Maybe because it was 40 feet.

Answer
Depending on the location of the main panel the ground rod can be connected to the panel or the actual meter base. The size of conductor used is determined in code table 250.66 and it is based on the size of the largest ungrounded service entrance conductor, which in common terms is the hot entrance conductor. For copper #4 is for a 2/0 or 3/0 and a #6 is for 1 or 1/0. I don't know what service size you have so I do not know the size the entrance conductor should be. If your existing rod is connected to the meter the second would also be connected to it. Thanks J
About Electrical Wiring in the Home
This site answers questions related to home electrical wiring, home wiring, general electrical help,and other electrical questions related to aleternating current (AC). You can find help on the National Electical Code, home electrical issues, wiring electrical outlets, installing lighting, electrical grounding, and general electrical help for do-it-yourself projects not require an electrician. If you do not see your home electrical wiring question answered in this area then please ask your electrical wiring question here

Electrical Wiring in the Home

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J Cook

Expertise

General electrical wiring, including but not limited to, residential, panelboards, control wiring, low voltage wiring, Heating and A/C control wiring, single and three phase wiring.

Experience

I have been doing electrical since high school. I have been licensed by the State of North Carolina for ten years and am currently the Building Maintenance Superintendent for a municipality. I have extensive control wiring experience.

Organizations
Refrigeration Service Engineers Society.

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