Over the weekend I was working on some coaxial cable issues in my Dad’s basement when I noticed what I thought at first was a loose coaxial cable that had no terminal. Upon closer inspection, I realized that it was thhw 8 gauge wire that was connected to nothing. When I traced the line outside it was connected to a grounding rod. I opened the fuse panel to see if the line had been cut. The only grounding line I found was the one from the water line into panel, and it appears to be 4 gauge. The house is approx 5 years old in Bucks, PA. The panel is a 200 AMP panel. Is this wire size the correct size for the panel (I have read that 4 gauge should be used, but just checking)? If not was this wire size ever allowed and should there be a big concern about the undersized wire.
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Greetings slowone, As a first time poster Welcome to Breaktime.
This post, in response to your question, will bump the thread through the 'recent discussion' listing again which will increase it's viewing.
Perhaps it will catch someone's attention that can help you with advice.
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I'm guessing that #8 ground was installed for telephone or cable TV use.
However, the breaker panel should be grounded to more than just the water pipe. I forget the details but I believe that code now requires another ground, preferably a "UFER", in addition to the water pipe.
#8 is commonly used for the water bond, for connecting ground bussbars, and for providing a tail to connect with the various ground wires from the CATV, alarm system, phone, etc.
#4 is commonly used for connecting the panel to the ground rod, Ufer, or other electrode.
Since the place is but 5 years old .... I suspect that the #4 was intended to be connected to the rebar in the slab (Ufer) as the ground electrode, and the #8 to the water pipe. Just a guess.
As long as there's a good length of metal water pipe in the ground, you have a good electrode. The joker in the deck is that the metal may transition to plastic as soon as it leaves the house. There's no easy way to tell.
If nothing else, I'd find a piece of rebar in the slab, and attach the #8 to that.
renosteinke:
Thanks for the reply. It almost appears that they did connections backwards. The # 4 ground is running to the water/gas lines that penetrate through the basement wall. The #8 is running to the ground rod. Do you still see any problems with this, is there a need to run something larger to the ground rod? I'm just looking out for the folks to make sure their system is right.
The #8 to the ground rod may actually be in compliance with the NEC; the largest such wire called for in the NEC is #6. Local rules, however, often call for #4. In any event, the wire to the ground rod has precious little to do with clearing faults, and plenty to do with lightning protection. It is far more important that the ground rod (or it's equivalent) be in good contact with the earth. Testing has shown that it's almost impossible to make a better "ground rod" than you make when you use the rebar in the foundation ("Ufer"). So, chances are that you'll be fine with things as they are. It would remove all question if you switched them, or replaced the #8 with #4 ... but I wouldn't lose sleep over it.
renosteinke:
Thank you for taking the time to answer my question.