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Old 02-14-2012, 02:43 PM   #61
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Multiple Ground Rods, help


That and if somebodies kids were out there playing around with dads cresent wrench(you know like most of us did! )and happens to pull the clamp lose on the 1st one the clamp will still be looped on the wire and the other end will still be hooked hopefully

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Old 02-14-2012, 03:00 PM   #62
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Word of advice to everyone here. DO NOT hire any contractor that does not get permits and inspections. Even if the contractor claims it's not required. These kind of contractors are lazy and lazy contractors are the kind of people who will mess up any work they're doing and not even care. They are by no means professional. This is your house, where you live, you do not want people messing it up.

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Old 02-14-2012, 03:03 PM   #63
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It depends on what the job is,many places dont require a permit for jobs under $500.00
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Old 02-14-2012, 04:52 PM   #64
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I should not have to explain to a contractor the relationship between fully burring a ground rod and having a low-resistance grounding system.
In most cases grounding rods will NOT provide a low resistance grounding system. The code also says rods should me at least 6' apart not exactly 6' apart.
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Old 02-14-2012, 05:01 PM   #65
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Resistance depends on the soil conductivity and how deep the rod is buried not the fact that its a rod. Also, by code a second rod does not need used if the resistance is below 25ohms. see: Nec 250.53
No kidding?
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Old 02-14-2012, 05:04 PM   #66
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No kidding?
If you knew all that then what was the point of this:

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In most cases grounding rods will NOT provide a low resistance grounding system.
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Old 02-14-2012, 05:08 PM   #67
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If you knew all that then what was the point of this:
The point was that your belief that ground rods provide a low resistance electrode is many times incorrect.
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Old 02-14-2012, 05:15 PM   #68
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The point was that your belief that ground rods provide a low resistance electrode is many times incorrect.
Please stop making stuff up!!!!!!!!!! I never said any one grounding system is low-resistance or lower resistance in comparison to another. I only stated the grounding system should be low-resistance, below 25ohms, as this is what's required by code.
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Old 02-14-2012, 05:17 PM   #69
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Now ya notice Brric's avitar says master electrician,Ive got a few licenses,Speedey Petey is licensed,Jim Port is licensed.........?
Are you catching a pattern here Jasin?
I'm going to continue to stand by my, do it right to begin with.
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Old 02-14-2012, 05:17 PM   #70
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But it's only required to be below 25 Ohms if you're using a single rod.

Drive a 2nd and nobody cares what it is, it could be 2000 ohms..
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Old 02-14-2012, 05:43 PM   #71
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Jasin,

I'm going to go ten feet with the second ground rod simply because that puts it directly under my phone and satelite entry boxes/ground wires.

Siemens and some others (maybe Mike Holts) depict and/or recommend installing the additional ground rods in close proximity of such equipment. It's won't cost but a few dollars more so no biggie.

I did not realize ground rods were supposed to be driven completely underground though! Virtually every ground rod I've ever seen in Alabama and Mississippi are all clamped just above the surface. Is that a new code?

Thanks.


P.S. Much of this has been hashed over already so maybe better to let some points rest.


Now back to
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Old 02-14-2012, 08:13 PM   #72
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I'm not using google i'm using my brain. Nevertheless, the equation is: R=2paR

Not hardly ..... I would suggest 'grounding' google ...


Though it has been entertaining I would suggest that all the BS come to an end.
No one here ..including me... has any business trying to pass themselves off as someone who knows anything about soil resistivity testing, ground rod resistance or what is actually considered a low resistance ground for purposes of equipment protection like computers and entertainment systems.

These calculations are done by engineers using computer software to deal with the math. It is involved ... to say the least. Which is why they have test equipment for field use ...

You are very limited as a home owner as to what you have the capability to accomplish. Unless your pockets are giant deep.

You cannot reach levels of low resistance of 2 or 3 ohms which is required in order to have maximum capabiltiy to protect sensistive equipment with 8' ground rods. In fact your going to be lucky to have 25 ohms average resistance for multiple rods. You might not be able to get below 100 ohms. So adding ground rods by more than 2 may not gain you a dang thing.

To get this so called low resistance you would need to get your ground rods 30 feet deep or more. I understand you can use a variety chemicals poured in the bored hole after setting a ground rod to increase soil contact which will also help for a shallow driven ground rod....30 feet or less.

Also remember lightning doesn't much care about ground rod resistance or soil resistance it will overcome it easily. So about all you can do is protect your home from transient voltages and power company surges and proximity lighting strikes that are containable with the technology available to a home owner. Many of these events you will not have anything that is going to save the day so to speak.

You need also remember the NEC did not have in mind saving your electronics by augmenting with grounding rod or rods. They were wanting premise system grounding to protect your homes wiring and keep the spikes within the insulation of your wires and a few other concerns like potential differences on metal and voltage stabilization in the event of a lost service neutral..

Now the brief summary I'm posting has nothing to do with my knowledge ... I'm sitting here reading over some books I have (some old some new) on achieving a low resistance ground for the protection of sensitive equipment. And it is apparent to me you are very limited in accomplishing that with shallow driven ground rods.

Just my two cents worth.

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Old 02-14-2012, 09:31 PM   #73
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Well, that wraps up another one when a few can't play together it ruins it for the rest.

OP, if any more questions, please start another thread, thank you, Gary

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