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.
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!)
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?
[This message has been edited by Ann Brush (edited 11-30-2006).]
#124690 - 11/30/0602:57 PMRe: Ground rod installation
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.
#124693 - 11/30/0608:23 PMRe: Ground rod installation
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
#124694 - 11/30/0610:48 PMRe: Ground rod installation
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).]
#124696 - 11/30/0611:36 PMRe: Ground rod installation