placement of ground rod

[kwired]

Thank You Gold; Can you define what the permanent moisture level is? I am sure that it is different from El Paso vs Seattle.

I am pretty certain whatever it is it changed a couple years ago here during a dry spell, but has since pretty much recovered.

I think keeping the rod away from the foundation wall (where there is a basement) also probably helps some with it's sphere of influence, but NEC doesn't mention this either.

As far as keeping out from under a roof overhang, doesn't the wind ever drive the rain in TN to some angle other then true vertical? It sure does here.

 

[mwm1752]

Mike Holt has a video where he tested ground resistance, he did get well below 25ohms but that was after using five 10' ground rods coupled together drove down 50'. It's a very interesting video. Here is the link.

I have seen this one thanks, how about the word practical in 250.53(A) -- is it practical to pull out a ground rod after it has been driven in? And in my earth digging experience from post holes to gardening I would say that the max depth I have ever dug with out finding moist earth -- 10" maybe anyone else seen deeper -- I have not dug in the sahara desert.

 

[petersonra]

I have seen this one thanks, how about the word practical in 250.53(A) -- is it practical to pull out a ground rod after it has been driven in? And in my earth digging experience from post holes to gardening I would say that the max depth I have ever dug with out finding moist earth -- 10" maybe anyone else seen deeper -- I have not dug in the sahara desert.

Look carefully at what word is actually used.

The word used is practicable, not practical.

Practicable is not defined in the code nor is it in NFPAs list of defined terms.

It therefore means whatever the dictionary NFPA says to use says it means.

Best I can tell "if practicable" means "if it is possible".

 

[kwired]

And in my earth digging experience from post holes to gardening I would say that the max depth I have ever dug with out finding moist earth -- 10" maybe anyone else seen deeper -- I have not dug in the sahara desert.

Two maybe three years ago when it was pretty dry - and we did not have the worst of the dry spell in my area, I was having much more difficulty then usual digging 3 -4 foot deep trenches because it was dry and very hard, and this was in heavier soil. Just how dry was the soil IDK, but it come out of trencher fairly powdery and if you grabbed a handful and compressed it, it didn't have enough moisture to want to remain in a clump like it normally would in years with average or above rainfall.

Sandy soils which are also in some areas around here do get very dry easily if they haven't had rainfall or irrigation.

 

[mwm1752]

Two maybe three years ago when it was pretty dry - and we did not have the worst of the dry spell in my area, I was having much more difficulty then usual digging 3 -4 foot deep trenches because it was dry and very hard, and this was in heavier soil. Just how dry was the soil IDK, but it come out of trencher fairly powdery and if you grabbed a handful and compressed it, it didn't have enough moisture to want to remain in a clump like it normally would in years with average or above rainfall.

Sandy soils which are also in some areas around here do get very dry easily if they haven't had rainfall or irrigation.

So in your circumstance probably wouldn't have made much difference where the ground rod was driven --

 

[mwm1752]

Look carefully at what word is actually used.

The word used is practicable, not practical.

Practicable is not defined in the code nor is it in NFPAs list of defined terms.

It therefore means whatever the dictionary NFPA says to use says it means.

Best I can tell "if practicable" means "if it is possible".

Another definition: "capable of being put into practice" so if the rod is not able to be "embedded below permanent moisture level" because the soil is dry and permanent moisture is not avaliabe then you are not required to place the rod in any designated location. An area that accumulates moisture such as below a down spout may be a better location but does not result in permanent type moisture.

 

[kwired]

So in your circumstance probably wouldn't have made much difference where the ground rod was driven --

In some instances yes. Other areas maybe had irrigation that still contributed to soil moisture, but some of the digging I had done at that time in non irrigated areas was kind of brutal compared to normal years. One time that year I was figuring on spending maybe an hour to two trenching with my small trencher a line about 100 feet max - soil was so dry and hard it took all afternoon to dig that trench.