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For a 200 amp 2 family overhead service I am using a primary and a secondary ground. A #6 stranded copper to two ground rods and a #4 stranded copper to the water meter. My question is, do I run the ground wires to the meter bank or to the panels? I believe it is the meter bank but just want to make sure. Thanks for your help.
I'm not sure that's the optimum thing you want to do and I'm not sure what you mean by primary and secondary grounds.
There are meter boxes with two 100 amp breakers that will accept a 200 amp service. There is even one that will accept a 400 amp servive and give you two 200 amp services. See Midwest Electric Products, Inc..
That makes for a nice clean installation and the best place for the ground rod would be the meter box.
If your using two 100 amp panels, then you have to connect the ground rod at the meter and your 100 Amp panels will have to wired like sub-panels with isolated grounds and neutrals. It is permissible to use a breaker rated the same or higher than the main to use as an alternate interior disconnect, if desired.
You will need an approved method of connecting two separate circuits to the main panels at the meter.
There is a limitation on the distance between the meter and the main pannels have to be without having a disconnect outside. Furthermore, the AHJ may require an outside disconnect.
When using two ground rods be aware that there is a separation distance required. The scicky in this forum has a way to read the NEC code. You can't search, nor print, but you can read.
A reminder that it is suggested that other utilities such as phone and cable terminate at the same place the ground rod is located. Generally it's not a requiremet.
I know it didn't directly answer your question.
More than likely you have gotten your answer from someone else by now, being that a month has passed since your question posted, but here goes nothing. If you have a two meters enclosure outside with no breakers on them you will need to run your #4 from the water main, and your #6 from your ground rods, which BTW need to be a minimum of 6' apart, to both of your inside panels continuously. Please remember that you are never to install any earth grounds to a meeter enclosure unless it is a combination device where in there is a main means of disconnect and a meeter socket. All grounding is equally important, there it no primary and secondary grounding there is your water ground, and there is your earth ground both equally important and they should always be bonded to your main means of disconnect, or disconnects, no matter how many you have.
I hope this helps!
Sincerely, Tommy Schnak:cool:
I have to say Tommy, there most certainly CAN be a "primary" grounding electrode.
It is not given this name in the NEC but it is implied.
Here's what I mean:
III. Grounding Electrode System and Grounding Electrode Conductor
250.50 Grounding Electrode System
All grounding electrodes as described in 250.52(A)(1) through (A)(6) that are present at each building or structure served shall be bonded together to form the grounding electrode system. Where none of these grounding electrodes exist, one or more of the grounding electrodes specified in 250.52(A)(4) through (A)(7) shall be installed and used.
The words "that are present" are very important. A ground rod is NOT present when a house is built, a metallic water pipe IS (if that's what's being used).
Then we see 250.52(A)(1) Metal Underground Water Pipe and 250.53(D)(2) which tells us that if a water pipe is used as an electrode it must be supplemented by at least one more electrode.
SO, in a system with a metallic water pipe feeding a house the water pipe is the primary electrode and the ground rod is a supplemental electrode.
And Tommy, why the negative for KISS. He did give related info and does admit he did not answer the question directly. The reference to a 400A service was simply for comparison.
I'm not sure why I missed this question before. I probably just overlooked it.
I personally don't give a crap about the red and green boxes. I tell it like it is which has earned me quite a few reds. Some folks just can't handle the truth.
I'm just here to help folks, but some here do put quite a bit of stock in those boxes.
Sorry bud, but I think the negative was uncalled for.
Stan, where can I get a copy of the Implied electrical code, because the last time I checked it doesn't exist. Sorry for the sarcasm but Keepitsimple did not stand by his name, his answer was extremely confusing. All I'm trying to say is the reason that the NEC does not use the terminology Primary, and secondary, when referring to grounding is because it would really confuse things as you have done by defending KISS terminology. I am not a negative person I just want to K.I.S.S.;) By the way you are very well written, and seem extremely knowledgeable, I will try to live by your example and be less negative, and more helpful:cool:
Although I and our jurisdiction [excluding some inspectors :D] agree, this is not true for all jurisdictions. Some areas will allow you to install your EGC, and GEC in a non meter/Main combo..Quote:
Please remember that you are never to install any earth grounds to a meeter enclosure unless it is a combination device where in there is a main means of disconnect and a meeter socket.
I agree that there may be areas in the US where the AHJ may allow the GEC to be connected to the meeter pan instead of the main means of disconnect. However, if you refer to the quote above you will notice that it is a "two family residence" that is in question. This would not be permissible by the NEC in this instance.Quote:
Originally Posted by Rafferty
I hope this helps!
Sincerely, Tommy Schnak:cool:
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