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Posted By: renosteinke Ground rod installation - 11/30/06 05:05 PM
This is a particularly good pic of a ground rod installed in compliance with our local practices.

Please note that it differs in the details from the way it is done in most places. In some ways, it is also a good example of what was once, for a period in the '70's, of the "NEC way," though that is no longer the case.


[Linked Image]


You first have to appreciate that our area is both quite rocky, and dry. Our AHJ's want the GEC completely protected by EMT. The rod should be set in the 'drip line' of the roof, to improve the chances that the earth will be moist. The top of the rod needs to be exposed, for inspection. In this case, the nearly flat top of the rod started out as a cone; impacts from the driver flattened it. (And this was an easy one!)
Posted By: Ann Brush Re: Ground rod installation - 11/30/06 07:41 PM
And while we have ensured the electrical equipment is adequately grounded we have also ensured that someone will be going to the hospital for stiches after tripping over or falling onto that rod. I have two little kids and that is a text book case for an accident waiting to happen. NEC compliant or not, if that were my house the rod would be removed or buried completely.

Has a water pipe grounding connector been used to connect to the rod - that's a no-no here?

Edited typo.


[This message has been edited by Ann Brush (edited 11-30-2006).]
Posted By: sparky806 Re: Ground rod installation - 11/30/06 07:57 PM
That would fail here in Kansas City. All 8 feet of rod must be in contact with earth. 7'-10" doesn't cut it. Also not protected from damage. We all know what a lawn mower blade will do yo it.
Richard
Posted By: Steve Miller Re: Ground rod installation - 11/30/06 10:03 PM
That would pass here but once it's inspected it has to be driven the last few inches.
Posted By: ShockMe77 Re: Ground rod installation - 12/01/06 12:40 AM
Is the EMT likely to become energized?

I ALWAYS drive the rod down to just below grade level and then clear out some of the dirt around the rod so the AHJ can clearly see it. This way there is no need for a return trip just to drive the rods down to below grade level. And in New Jersey we have to drive (2) ground rods, not one.
Posted By: renosteinke Re: Ground rod installation - 12/01/06 01:23 AM
Ann, technically speaking, this local practice does not comply with the NEC. The NEC likes them close to the wall, and completely buried.

This location was a rare one, in that there is actually a nice lawn! uauallym the rod location is on a slope, in the middle of a row of shrubs, etc, so the tripping hazard would not exist. If it makes you feel any better, I think the rod is still within a foot of the wall.

The NEC actually used to like the rod at the 'drip line', for better conductivity. Then, as noted here, the gardner started hitting them with the lawnmower- this led to heavier wire, solid wire, and, finally, calling for the wire to be in pipe. That, in turn, led to all sorts of debate over how to connect it to the rod.

As for the 8ft issue, here thay address that by requiring 10ft rods. Of course, many is the time I could only get 6ft. in the ground ... so I usually end up driving two rods [Linked Image]
Posted By: Ann Brush Re: Ground rod installation - 12/01/06 03:48 AM
Theoretically speaking what happens if "The wise man built his house upon the rock" literally?
Posted By: SteveFehr Re: Ground rod installation - 12/01/06 04:06 AM
You don't have to install the electrode vertically. If you have 6' of soil over bedrock, you can drive that 8' rod at a 45 degree angle. In an extreme case, you can bury it in a horizontal trench.

For a house built on solid rock with no topsoil, I'd venture that a ground rod is probably not the best choice of grounding- other methods are acceptable, too, and installing bonded rebar or a copper loop in the concrete foundation is probably going to be a better bet.

Honestly, I don't know why this isn't done more often. It's trivial for the masons to embed 20' of #6 in the footer, and leave a pigtail for connection at the panel. Why don't we ever see this? It would be well protected and offer an excellent ground- even better if it were also bonded to the rebar.

[This message has been edited by SteveFehr (edited 11-30-2006).]
Posted By: renosteinke Re: Ground rod installation - 12/01/06 04:36 AM
We do, Steve ....NOW. While the "Ufer" was developed in WW2, it was not accepted by the NEC until the mid-60's.

Every ground rod I have driven has been for a service upgrade- where the older system had only a "water bond."
Posted By: iwire Re: Ground rod installation - 12/01/06 10:39 AM
John I could not walk away from that.

I see someone tripping on that rod or worse tripping on something else and landing face first on that rod.

On a construction site that would need a 'rod cap' to protect workers from injury.

I understand each area has their own practices but in my opinion leaving the rod sticking up like that is asking for injury's.

Bob

[This message has been edited by iwire (edited 12-01-2006).]
Posted By: renosteinke Re: Ground rod installation - 12/01/06 01:53 PM
Iwire, you might have a valid point of view. This install, however, is EXACTLY what the local AHJ prescribes. Had I buried it, that would have caused some problems at inspection time. Heck, I'm lucky they don't insist on a full 10" above ground, so that they can read the stamping!

Now, the picture might be a bit deceptive; the -maybe- 2" of rod sticking up is not enough for a rod cap to grip. Heck, the diameter is small enough that I have trouble keeping the smallest caps on the rods I have in my garden!

Now, to be fair, I DID drive the rod as far as the rod-driver would allow. To go any deeper, I would have needed to dig. And that, as noted earlier, would have raised further issues at inspection.

Not visible is also the local insistance on #4 solid copper for the GEC. That is always a real joy to attach to the ground clamp. Those of you who use "acorns" have no idea how easy you have it!
Posted By: Trainwire Re: Ground rod installation - 12/04/06 01:52 PM
Reno,

Maybe you can answer this question.

Would it work in your area, to weld a cheap Carbide concrete bit on the end of the ground rod, or braze if you are using a solid copper one, and then drive the rod with your sds hammer drill?

I have a couple of area's here on the rail road where the rock is sticking up out of the ground, and where do you think the relay boxes go? That saves them from getting run over by lawnmower man!

TW
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