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#90805 - 12/11/04 04:46 PM Dual Ground Rod Bending Direction
mustangelectric Offline
Member
Registered: 02/08/04
Posts: 494
Loc: Bentonville, AR
Hi,
I figure the Subject of this message will make a few people scratch their head!
If I place two ground rods 6 feet apart but hit bedrock with the second rod and it is in a 2 foot deep trench which way can i bend the rod? Towards the first or away from the first.

I got it down about 4 feet and it would not go any further.

thanks for any replies or comments..

-regards

Greg
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#90806 - 12/11/04 06:29 PM Re: Dual Ground Rod Bending Direction
Ryan_J Offline
Moderator
Registered: 08/19/03
Posts: 1374
Loc: West Jordan, Utah, USA
If you're hitting solid rock, I would think you are screwed either way. I would be willing to bet that the parralleling efficiency would be better if they were angled away from each other, but I would also be willing to bet that you would not get 25 Ohms, even if you drove a half dozen of them!
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#90807 - 12/11/04 06:47 PM Re: Dual Ground Rod Bending Direction
mustangelectric Offline
Member
Registered: 02/08/04
Posts: 494
Loc: Bentonville, AR
Hi,
The firts rod drove in all the way, the second rod located 6 feet away went down 4' the stopped the trench was 2' deep.

Once it is backfilled isnt this in compliance?

-regards

Greg
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#90808 - 12/11/04 06:55 PM Re: Dual Ground Rod Bending Direction
BigB Offline
Member
Registered: 03/31/04
Posts: 719
Loc: Tucson, AZ USA
I had a similar situation, however I could get neither rod to go more tham 3 feet anywhere on the property. I was using a Bosch demolition hammer with grd rod attachment. I finally pulled them both out (by twisting them with a pipe wrench) and drove them at a 45 degree angle. They went to the bedrock then slid along on top of it. The inspector didn't even question it.
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#90809 - 12/12/04 05:21 AM Re: Dual Ground Rod Bending Direction
winnie Offline
Member
Registered: 09/15/03
Posts: 649
Loc: boston, ma
Mustang,

I don't believe that you are permitted to bend the rod, but I believe that you are fine if you bury the _entire_ rod horizontally at a depth of 2 feet.

Where does this trench extend? Have you considered using a ground ring instead of rods?

-Jon
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#90810 - 12/12/04 05:28 AM Re: Dual Ground Rod Bending Direction
electure Offline


Member
Registered: 12/24/00
Posts: 4259
Loc: Fullerton, CA USA
Winnie,
Could you explain further? Why would a rod have to be straight?

mustang's right. Now I'm scratching my head
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#90811 - 12/12/04 05:33 AM Re: Dual Ground Rod Bending Direction
earlydean Offline
Member
Registered: 12/22/03
Posts: 751
Loc: Griswold, CT, USA
Bend the rod away from the first.
The NEC only requires 8 feet of rod in contact with the earth, six feet apart.
If you are concerned with the rod's length, then add a third rod in a triangular pattern.
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Earl
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#90812 - 12/12/04 06:36 AM Re: Dual Ground Rod Bending Direction
trekkie76 Offline
Member
Registered: 06/19/04
Posts: 220
Loc: baileyville, maine, usa
The trench would have to be at least 2.5 ft deep. The section only talks about driving the rod to a depth of 8 ft, or where bedrock is encountered, buried in a trench. can't see where they talk about bending it, other than having 8 ft in contact with the soil.
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#90813 - 12/12/04 08:51 AM Re: Dual Ground Rod Bending Direction
dmattox Offline
Member
Registered: 10/20/04
Posts: 265
Loc: Anaheim, CA
See 250.53(G)

If you hit bedrock you are allowed to drive at up to a 45 degree angle. If you still hit bedrock at a 45 degree angle you then can bury it in a trench that is at least 30" deep.

You may not bend the rod unless its more than 8' long. You must use connectors that are rated for direct burrial.

You need to make sure that at any point the 2 ground rods are at least 6' away.
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#90814 - 12/12/04 09:12 AM Re: Dual Ground Rod Bending Direction
dmattox Offline
Member
Registered: 10/20/04
Posts: 265
Loc: Anaheim, CA
I was bored and wanted to try out my MSPaint skills

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