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Fencepost
Re: ground rods

Seems I've heard that the code stipulates that the grounding conductor from the panel to the ground rods must be unbroken (no breaks or connections allowed in the wire), so some inspectors have interpreted this to mean that you must go from the panel to the first ground rod, passing the wire through the clamp without cutting it, to the next ground rod. Since only one conductor to the grounding electrode system is required, electricians run only one wire, daisy-chaining the ground rods, because it's cheaper than running a separate home-run wire for each ground rod.

Theoretically, because the voltage potential at the location of each ground rod *could* be different, you could end up with a current flowing through the ground wire between the rods. If the wires are home-runned, this means that the current would be flowing through the panel, and a failure of one of the connections could result in a voltage differential between supposedly-grounded components. In reality, the voltage differential should be so small as to be insignificant.

I think that home-running each ground rod would be technically superior. It's just that it costs more to do, it's only insignificantly superior, and the daisy-chain method satisfies the code requirements in most AHJ interpretations.

JLMCDANIEL
Re: ground rods
rtirwin wrote:

you need to do your home work

I did my homework and you are flat a** wrong.

Jack

Mastercarpentry
Re: ground rods

I don't know about the exact codes but I'll give you this and run away from here. As a Ham radio nut who deals with towers that sometimes get direct lightning strikes, I get to deal with grounding for lightening protection quite a bit. Everything on that subject says to have a minimum of three 8' or longer solid brass rods spaced at least one rod length apart from each other, the first rod being within 15' of what you're grounding, and with all tied together through one 6ga. solid conductor which is then continued to whatever is being grounded. This has proven to be enough in most cases of a direct hit, where you need more is in poorly-conductive soil. There you use more and longer rods, always using one solid conductor of at least 6ga. in size. I'm also familiar with the buried grounds used in commercial steel structures where all the steel columns are bonded together through a buried loop around the entire building perimeter- equally or even more effective than just ground rods.

Another part of this end of things is that ground loops (a series circuit) and ground current differentials can destroy sensitive electronics without the help of lightning. Whatever you do to ground, you always tie all grounds together then make one single run into the shack where you ground all the equipment you're protecting individually and directly, and it is always tied into the home's grounding system equally well before it enters the shack.

All I know is that this method works very well to dissipate lightning's effects and also provides a very effective path to ground for failed equipment that needs to get rid of several thousand volts somewhere- hopefully not through you.

I trust this method with my life and have never heard of it failing anyone as long as it was done and maintained properly, You do whatever you want to; that won't affect this remodeler who leaves the heavy electrical work to a licensed electrician.

Happy warring (and happy wiring too!)

Phil

keith3267
Re: ground rods

"Another part of this end of things is that ground loops (a series circuit) "

A ground loop meets all the criteria of a parallel circuit and none for a series circuit. A daisy chain circuit can be either parallel or series and I think you are confusing the definition of daisy chain with the definitions of series/parallel.

I wish I could draw the schematic in one of these boxes. (Mac, Safari)

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