Yet Another Ground Rod Question!

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Split Bolt

Split Bolt

Senior Member
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Northern Virginia
I just looked at a service change job on an older house. Normally, the ground rods will go in near the point where the SEC enters the house for convenience. This house has an overhead service and below the meter location is poured concrete that connects the driveway, carport, sidewalk and front steps. I don't want to drill 2 holes in the concrete and leave something that looks like crap right where everybody walks past on the way to the front door! I am thinking about fishing the supplemental grounding electrode conductor across the basement along with the grounding electrode conductor (the main water shutoff valve is on the other side of the basement) and driving the dual ground rods on the other side of the house. I can't see where this would be a violation, but wanted to put it out here to see if I'm missing something.

Also, while looking into this, I noticed this in the NEC (both '05 & '08): "250.53(B) Electrode Spacing. Where more than one of the electrodes of the type specified in250.52(A)(5) or (A)(7) are used, each electrode of one grounding system (including that used for air terminals) shall not be less than 1.83 m (6 ft) from any other electrode of another grounding system. Two or more grounding electrodes that are bonded together shall be considered a single grounding electrode system." Does this mean that I cannot drive either one of my 2 ground rods (supplemental electrode) within 6' of where the copper underground water main (grounding electrode) passes?:confused:

Thanks in advance!
 
Split Bolt said:
I just looked at a service change job on an older house. Normally, the ground rods will go in near the point where the SEC enters the house for convenience. This house has an overhead service and below the meter location is poured concrete that connects the driveway, carport, sidewalk and front steps. I don't want to drill 2 holes in the concrete and leave something that looks like crap right where everybody walks past on the way to the front door! I am thinking about fishing the supplemental grounding electrode conductor across the basement along with the grounding electrode conductor (the main water shutoff valve is on the other side of the basement) and driving the dual ground rods on the other side of the house. I can't see where this would be a violation, but wanted to put it out here to see if I'm missing something.
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No problem......The length of the GEC is not addressed in the NEC but keeping it as short as possible is the best choice.
splitbolt said:
Also, while looking into this, I noticed this in the NEC (both '05 & '08): "250.53(B) Electrode Spacing. Where more than one of the electrodes of the type specified in250.52(A)(5) or (A)(7) are used, each electrode of one grounding system (including that used for air terminals) shall not be less than 1.83 m (6 ft) from any other electrode of another grounding system. Two or more grounding electrodes that are bonded together shall be considered a single grounding electrode system." Does this mean that I cannot drive either one of my 2 ground rods (supplemental electrode) within 6' of where the copper underground water main (grounding electrode) passes?:confused:

Thanks in advance!
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I'd say yes, keep the electrodes 6' away from each other.
 
I'd so no. 250.53(B) says "each electrode of ONE grounding system shall not be less that 6ft from any other electrode of ANOTHER grounding system."

You seem to be installing supplemental electrodes required by 250.53(D)(2). Those electrodes bonded together would makeup one "grounding system" for the service.
 
david luchini said:
I'd so no. 250.53(B) says "each electrode of ONE grounding system shall not be less that 6ft from any other electrode of ANOTHER grounding system."

You seem to be installing supplemental electrodes required by 250.53(D)(2). Those electrodes bonded together would makeup one "grounding system" for the service.
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I don't agree, in your scenario if you have a UFFER/foundation you would have to keep the water service, if metal, 6 feet from the foundation. :D food for thought
 
acrwc10 said:
I don't agree, in your scenario if you have a UFFER/foundation you would have to keep the water service, if metal, 6 feet from the foundation. :D food for thought
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mcclary's electrical said:
That's not what he said at all. HIs post means just the opposite
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Thanks, McClary. That's exactly what I'm saying. When the electrodes are part of the SAME grounding system, there is no requirement to separate the electrodes.

When they are for different grounding systems (I think the intent is when you have electrodes for a lightning protection system, etc.) you would have to separate the electrodes by at least 6ft.
 
Split Bolt said:
I am thinking about fishing the supplemental grounding electrode conductor across the basement along with the grounding electrode conductor advance!
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Why would you not run the GEC sized per 250.66 to your water pipe and tap a No. 6 to the driven rods???

Split Bolt said:
Also, while looking into this, I noticed this in the NEC (both '05 & '08): shall not be less than 1.83 m (6 ft) from any other electrode of another grounding system. Thanks in advance!
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Section (B)actually states that the electrodes of one system must be 6 feet away from the electrodes of another system. You appear to only have one system seeing that all the electrodes at the structure are required to bonded together.

The Rods are required to be at least (a minimum of) 6 feet from each other to take advantage of the earths conductive layers.

You do not need to drive a second rod (unless the first has a earth resistance of more than 25 ohms)
 
cpal said:
Why would you not run the GEC sized per 250.66 to your water pipe and tap a No. 6 to the driven rods???



Section (B)actually states that the electrodes of one system must be 6 feet away from the electrodes of another system. You appear to only have one system seeing that all the electrodes at the structure are required to bonded together.

The Rods are required to be at least (a minimum of) 6 feet from each other to take advantage of the earths conductive layers.

You do not need to drive a second rod (unless the first has a earth resistance of more than 25 ohms)
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I agree with you Charlie.

Split bolt, clarify for us, is this one GES for a single service?

Roger
 
SB, a single wire can be run for both electrodes. Run your #4 cu (or equiv) water-pipe conductor to the pipe clamp, and simply jump a #6 cu from the pipe to the nearest rod, and jump to the second rod.

As for the 6' spacing, two rods must be at least 6' apart, but I've never heard of there having to be 6' between a rod and an existing underground water pipe. Who knows which way a pipe runs underground?
 
Single family dwelling, single service. Going from 100A to 200A. House built in 1961. Everything is normal except that there's more concrete than lawn on the service side of the house.
 
Split Bolt said:
Single family dwelling, single service. Going from 100A to 200A. House built in 1961. Everything is normal except that there's more concrete than lawn on the service side of the house.
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Then as the others have said, run one #4 to the water and then a #6 jumper to the rod(s)

Roger
 
Look at the illustration below and ignore everything except the water piping and the rod.

1113918256_2.jpg


Roger
 
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