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Old 02-09-2012, 02:34 PM   #1
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Multiple Ground Rods, help


Hello All,
In anticipation of installing a whole house surge protector, I would like to insure having adequate earth ground.


At the moment we only have one 8ft ground rod, appears galvanized, which is grounded directly to our electric meter box (bonded to neutral). Our load center is next to the meter box and connected via metal conduit. In addition, I will be adding a subpanel directly under the load center for this project.


Anyhow.


1) The copper wire attached to the ground rod appears somewhat small? I don't have anything to compare it to but it is less than 3/16 of an inch and has a sharp bend in it (see photo).


2) Given the above, can I add and bond multiple 4ft ground rods with the existing 8ft ground rod, with one of those being only two feet from the existing rod?


I realize code says something about keeping them a minimum of 6ft apart, but is that only in assuring adequate grounding? I already have what Alabama considers adequate grounding with the one ground rod; however I will be adding a subpanel and would like to ground it to one of the new 4ft ground rods. It would be within two feet of the existing ground rod though.


In this way, I can insure using the proper copper wire and maintain a straight run(no bends). Otherwise, can I run the copper wire from the new subpanel and gently bend it underground to attach to the existing ground rod?


I would like to then add two more 4ft ground rods spaced 10ft apart. One would be under my phone panel and the other under my ac disconnect. Those could then be grounded directly as well and as Siemens depicts in their design guide. Everything will be bonded together of course.


Thanks
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Old 02-09-2012, 03:15 PM   #2
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Multiple Ground Rods, help


You do not need the ground rod for your sub-panel. the original one rod is all that is required assuming it tested 25 ohms or less. What is with all the 4 foot ground rods ?

If your wanting 'better' grounding then you need 8 foot rods.

Grounding electrode conductors going to ground rods need only be 6 awg copper. That looks like what you have.

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Old 02-09-2012, 03:37 PM   #3
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You do not need the ground rod for your sub-panel. the original one rod is all that is required assuming it tested 25 ohms or less. What is with all the 4 foot ground rods ?

If your wanting 'better' grounding then you need 8 foot rods.

Grounding electrode conductors going to ground rods need only be 6 awg copper. That looks like what you have.
What are good reasons for
. . .wanting 'better' grounding. . .?
An area that is prone to lightning?
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Old 02-09-2012, 04:44 PM   #4
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Multiple Ground Rods, help


The 4 foot ground rods and a second ground rod less than 6 feet from the 8 foot ground rod do not count unless the rods altogether meet the 25 ohm test using special equipment.

If you have two 8 foot rods at least 6 feet apart then the system passes without doing the 25 ohm test.

It is not necessary to remove "extra" ground rods.
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Old 02-09-2012, 10:26 PM   #5
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Multiple Ground Rods, help


Hello All,
I will attempt to answer everyone's question with this post.


1) I have no way of knowing for sure, minus paying someone $$$, as to whether our ground system would meet the 25ohm threshold. However, I would much prefer going overkill in this instance by adding a second 8ft ground rod or possibly several 4ft ground rods -versus- the alternative.


2) In addition, as I understand the copper wire going to the ground rod is supposed to be straight (minus bends). We however have two significant bends in ours. I could straighten it some but never fully.


3) I prefer to add 4ft ground rods, 10ft and 20ft from electric meter, because they are easier to drive. If one 8ft ground rod is better though I will go that route.

Also, I realize adding a ground rod in close proximity to the existing ground rod won't count. The only reason I contiplated that was in order to avoid having bends in the new copper wire coming from the new subpanel. It was really just a means by which to connect the new subpanel copper wire to the existing ground rod.


Is this an acceptable strategy or not? If not, what say you?



God Bless

Last edited by Ralph III; 02-09-2012 at 10:29 PM.
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Old 02-09-2012, 10:37 PM   #6
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Multiple Ground Rods, help


Run continuous ground wire from meter socket to all ground rods,no splices
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Old 02-09-2012, 11:15 PM   #7
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Attachment 45615
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Run continuous ground wire from meter socket to all ground rods,no splices
I cannot run a continous copper wire from my existing meter without having my power turned off. It would then have to pass inspection and possibly be a day or two later before I could get my power turned back on.

Is that really necessary anyhow? As I understand, you only need to connect the ground rods together via one continous copper wire. That is how Siemens depicts it as well as Mike Holts and others..


I could run a continuous copper wire from my new subpanel to the existing ground rod and then on to the proposed additional ground rods (see my diagram from earlier post).

Thanks, Ralph

Last edited by Ralph III; 02-09-2012 at 11:22 PM.
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Old 02-09-2012, 11:23 PM   #8
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Multiple Ground Rods, help


Ive always run a continuous ground wire,makes sense that it would have less resistance and have fewer parts to worry about.
But I could be wrong,Ive been told that before!
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Old 02-09-2012, 11:28 PM   #9
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Multiple Ground Rods, help


This way has always made sense to me anyway
But whatever you do make sure to pound the rods completely into the ground regardless off what this picture shows
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Last edited by plummen; 02-14-2012 at 05:54 PM.
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Old 02-09-2012, 11:46 PM   #10
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Ive always run a continuous ground wire,makes sense that it would have less resistance and have fewer parts to worry about.
But I could be wrong,Ive been told that before!
I guess you could with the simple setup as shown in your example.

Siemens however depicts running individual ground wires from the various panels (subpanels, phone panels, ac units etc) which is more applicable to my setup and connecting those to the ground rod system. Mike Holts also depicts similar.

All the details I've read just state to be sure the ground rods are connected together via one copper wire. Whereas all show the copper wire coming from the meter and various panels as being spliced pieces and clamped to the ground rods.

Take care, Ralph
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Old 02-10-2012, 12:05 AM   #11
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Multiple Ground Rods, help


Quote:
Originally Posted by Ralph III View Post
I guess you could with the simple setup as shown in your example.

Siemens however depicts running individual ground wires from the various panels (subpanels, phone panels, ac units etc) which is more applicable to my setup and connecting those to the ground rod system. Mike Holts also depicts similar.

All the details I've read just state to be sure the ground rods are connected together via one copper wire. Whereas all show the copper wire coming from the meter and various panels as being spliced pieces and clamped to the ground rods.

Take care, Ralph
This isn't a complicated process. The more fittings that you have the more chances for loose connections, but it's really not a big deal. Wire it up with as many or few connections that you want too.
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Old 02-10-2012, 03:39 AM   #12
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Multiple Ground Rods, help


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This way has always made sense to me anyway
Zoom into the 1990's and use MB circuit breaker panels
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Old 02-10-2012, 05:46 AM   #13
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For services of more than 100 amps and with a metal water pipe exiting the basement underground, you need a ground wire (grounding electrode conductor) fatter than #6 (#4 if copper for service 101 to 200 amps) from panel to pipe and this must be unspliced. For services 100 amps and under and with ground rods you need #6 as GEC unspliced from panel to a qualifying (8') ground rod.

The remaining grounding electrodes for the same building must be interconnected with additional #6 as GEC which may be hung off of (clamped to) other previously strung GEC that may be reached first.

Subpanels in separate buildings need just one 8' ground rod. The ground bonding back to the main panel is accomplished by the ground wire (equipment grounding conductor) accompanying the power feed and depending on the ampere capacity of the feed may be smaller than #6.
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Last edited by AllanJ; 02-10-2012 at 06:00 AM.
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Old 02-10-2012, 06:25 AM   #14
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Multiple Ground Rods, help


Quote:
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Zoom into the 1990's and use MB circuit breaker panels
That was just a picture I found with multiple grd rods
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Old 02-10-2012, 07:06 AM   #15
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Multiple Ground Rods, help


The 4 foot rods will not qualify as electrodes. You need to have 8' in contact with the soil.

You can add a jumper of #6 between the old and new rods. You will need an acorn clamp for each conductor.

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