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tomupnorth
join:2005-01-14
UpperMidwest

tomupnorth to 49528867

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to 49528867

Re: Surge Protection Residential Whole House

said by 49528867:

said by nunya:

I drive a rod on every pool with a sub-panel. As long as it is bonded back to the main with a #6 or greater, it's perfectly compliant. It's not required, but it's not a violation.

Yes and even though it is not required, by doing so you are providing your customer with a considerably safer electrical system.

Great, that makes me feel better, thanks.

Regarding my "single ground at pole, not at house or garage, but another at pool" I can only add that driving ground rods around here is next-to-impossible given the rock we live on.

I don't know how well a ground rod can work in (almost) solid rock, but I can't imagine it's good.

At least we don't have to worry about shifting foundations, but for everything else the rock here (I don't even want to call it "rocky soil" cuz there ain't much soil!) is a huge PIA.
49528867 (banned)
join:2010-04-16
Fort Lauderdale, FL

49528867 (banned)

Member

said by tomupnorth:

Regarding my "single ground at pole, not at house or garage, but another at pool" I can only add that driving ground rods around here is next-to-impossible given the rock we live on.

You have a few options, depending on the thickness of the rocky layer if you can drill through the rock and get to the soil underneath you can buy ground rods which connect to each other to extend the length allowing you to get a decent amount of rod into the soil.

If you cannot go down you might be able to trench horizontally (below the frost line if applicable) and achieve the same results by laying a bare conductor in the trench if you are limited in the length of you trench you can add a product before backfilling such as Erico GEM to enhance your grounds effectiveness.

»www.erico.com/products/GEM.asp

Wayne
tomupnorth
join:2005-01-14
UpperMidwest

tomupnorth

Member

said by 49528867:

If you cannot go down you might be able to trench horizontally (below the frost line if applicable) and achieve the same results by laying a bare conductor in the trench if you are limited in the length of you trench you can add a product before backfilling such as Erico GEM to enhance your grounds effectiveness.

»www.erico.com/products/GEM.asp

Now there is something I've never seen (nor heard of) before! Can't imagine we can get it from our local HD/Lowes though!

Or maybe we can--the local HD does have very-large-sheets of copper w/ground connection for this very purpose. Pricey as heck of course.

Jack_in_VA
Premium Member
join:2007-11-26
North, VA

2 edits

Jack_in_VA

Premium Member

said by tomupnorth:

said by 49528867:

If you cannot go down you might be able to trench horizontally (below the frost line if applicable) and achieve the same results by laying a bare conductor in the trench if you are limited in the length of you trench you can add a product before backfilling such as Erico GEM to enhance your grounds effectiveness.

»www.erico.com/products/GEM.asp

Now there is something I've never seen (nor heard of) before! Can't imagine we can get it from our local HD/Lowes though!

Or maybe we can--the local HD does have very-large-sheets of copper w/ground connection for this very purpose. Pricey as heck of course.

Ground Plate - An electrode made to the requirements of NEC article 250-52 (d). The material used shall be a copper alloy intended for the purpose with a minimum thickness of 0.060”. Each plate shall expose a minimum of 5 ft2 of surface area to contact the soil. Grounding conductors shall be attached to the plate using a welding process. Splices made to the grounding conductor shall be made using a welding process. Dissimilar metals and solder connections shall not be allowed. Usually installed in a horizontal position.

Achieving an Acceptable Ground in Poor Soil-EC&M Article

Ground Rods and Touch Voltages

Ground rods are not enough to protect from lethal voltages.
49528867 (banned)
join:2010-04-16
Fort Lauderdale, FL

49528867 (banned)

Member

In that article did you happen to catch this?

Always install multiple electrodes so they are more than 6 ft apart.

Wayne
tomupnorth
join:2005-01-14
UpperMidwest

tomupnorth to Jack_in_VA

Member

to Jack_in_VA
Ok after reading all this stuff, and finding also this page on ground methods I am officially too smart for my own good.

The link says conventional ground rods suck, and even if I *was* able to somehow dig a 30" hole for a ground plate, it'd work poorly and last about a week.



This has been fun though. Maybe I'll play amateur chemist and build-my-own electrolytic...


Jack_in_VA
Premium Member
join:2007-11-26
North, VA

Jack_in_VA

Premium Member

said by tomupnorth:

Ok after reading all this stuff, and finding also this page on ground methods I am officially too smart for my own good.

The link says conventional ground rods suck, and even if I *was* able to somehow dig a 30" hole for a ground plate, it'd work poorly and last about a week.



This has been fun though. Maybe I'll play amateur chemist and build-my-own electrolytic...


It does show that there is way more considerations to effective grounding than many people realize. I especially liked finding an article on Touch Voltage. I had that in a seminar a long time ago.

You have rocks but Sandy soil is also a challenge but thankfully here I'm on the water and the water table is high enough for the ground rod to contact.

garys_2k
Premium Member
join:2004-05-07
Farmington, MI

garys_2k to tomupnorth

Premium Member

to tomupnorth
said by tomupnorth:

Ok after reading all this stuff, and finding also this page on ground methods I am officially too smart for my own good.

The link says conventional ground rods suck, and even if I *was* able to somehow dig a 30" hole for a ground plate, it'd work poorly and last about a week.



This has been fun though. Maybe I'll play amateur chemist and build-my-own electrolytic...


I suspect calcium chloride may be a good salt to use -- it's definitely a desiccant and would draw moisture from the atmosphere.

robbin
Mod
join:2000-09-21
Leander, TX

1 recommendation

robbin to tomupnorth

Mod

to tomupnorth
said by tomupnorth:

said by 49528867:

If you cannot go down you might be able to trench horizontally (below the frost line if applicable) and achieve the same results by laying a bare conductor in the trench if you are limited in the length of you trench you can add a product before backfilling such as Erico GEM to enhance your grounds effectiveness.

»www.erico.com/products/GEM.asp

Now there is something I've never seen (nor heard of) before! Can't imagine we can get it from our local HD/Lowes though!

Or maybe we can--the local HD does have very-large-sheets of copper w/ground connection for this very purpose. Pricey as heck of course.

I've used Erico GEM before. It's very interesting stuff. Seems like black tile grout with a lot of carbon (graphite) in it. I'm sure that's not how they make it, but that is what it seemed like. Very messy, stains your hands black, dries hard. I added extra ground rods to my system using it. Used a rock drill mounted on a Bobcat Excavator to drill 6" holes 8 foot deep and installed traditional ground rods in the bored holes using the GEM product. You could also use a rock saw to cut a trench. Best place to get Erico products in my area is Graybar. They do not stock GEM in Texas last I checked, but they do keep it in one of their warehouses somewhere up north. As I recall, the GEM product and shipping came to about $125 per hole (10 years ago).
49528867 (banned)
join:2010-04-16
Fort Lauderdale, FL

49528867 (banned)

Member

said by robbin:

I've used Erico GEM before. It's very interesting stuff. Seems like black tile grout with a lot of carbon (graphite) in it.

Well consider this, Eirco builds Cadweld molds out of graphite so I am sure they have a silo or two of it on hand, then take that graphite powder and mix it with oh say some bentonite, add a touch of a chemical to lower ground resistance that will not attack copper or steel and meets the EPA leeching requirements, mix well and you have GEM.

And yes it is nasty to work with, I haven’t used GEM but have worked with a similar product sold by Harger.

»www.harger.com/

Wayne

robbin
Mod
join:2000-09-21
Leander, TX

robbin

Mod

I don't think GEM has bentonite in It. It hardens (sets up firmly according to Erico) much like cement does. It doesn't loose conductivity when it dries. When I researched it years ago, it seemed that they had done something other than adding graphite to bentonite. The GEM performance seemed to indicate that they had taken a different path.
tomupnorth
join:2005-01-14
UpperMidwest

tomupnorth to robbin

Member

to robbin
said by robbin:

Used a rock drill mounted on a Bobcat Excavator to drill 6" holes 8 foot deep and installed traditional ground rods in the bored holes using the GEM product. You could also use a rock saw to cut a trench.

Ah yes, it seems in Texas a real man needs either a skid-steer or a backhoe. I'd love both but have only a lowly Tractor. I've used a little Dingo trencher (nice for laying low voltage wire) but not one of the big rock saws--our contractor broke one laying our main house conduit. Took 3 days continuous to get thru one ~35ft leg of the trench.

Anyway I like the Bobcat idea but it would be hard getting it close to where I need to put my rods. Still toying with making some sort of steel extension for use with a large masonry bit and my 1" hammer drill. Oughta be able to weld something that would work. Maybe I will just ask our rental guys about this.

robbin
Mod
join:2000-09-21
Leander, TX

robbin

Mod

You can't drill a hole for a ground rod. They must be driven. The reason I went with GEM in a hole as opposed to a trench is than in summer the limestone dries out. I wanted to try to get contact with an area which may retain some moisture. The Bobcat was able to drill a 6" hole. Most everything and everyone else could only drill minimum of 9".
tomupnorth
join:2005-01-14
UpperMidwest

tomupnorth

Member

said by robbin:

You can't drill a hole for a ground rod. They must be driven. The reason I went with GEM in a hole as opposed to a trench is than in summer the limestone dries out. I wanted to try to get contact with an area which may retain some moisture. The Bobcat was able to drill a 6" hole. Most everything and everyone else could only drill minimum of 9".

No doubt your point is: if you drill a hole thru solid rock you aren't going to get any grounding benefit. I was hoping for SOME grounding benefit in that the rock here is a mix of granite and caliche.

But it might be a whole lot of trouble for a very-little-or-no benefit so thanks for turning me off to drilling.

I guess I should rent the Bobcat and plant a rod w/GEM as close as I can get it, then couple to the building service with #6 or bigger.
49528867 (banned)
join:2010-04-16
Fort Lauderdale, FL

49528867 (banned)

Member

said by tomupnorth:

I guess I should rent the Bobcat and plant a rod w/GEM as close as I can get it, then couple to the building service with #6 or bigger.

Do you plan to bond the sub buildings ground to the pole ground?

If so how are you going to get the wire from the sub building to the pole?

Wayne
tomupnorth
join:2005-01-14
UpperMidwest

tomupnorth

Member

Just a shallow trench.
49528867 (banned)
join:2010-04-16
Fort Lauderdale, FL

49528867 (banned)

Member

said by tomupnorth:

Just a shallow trench.

Then drop a bare conductor in there and backfill it with some GEM and there's your ground for the sub building.

Wayne
tomupnorth
join:2005-01-14
UpperMidwest

tomupnorth

Member

Bare conductor...more GEM...hmm, that makes too much sense! Thanks!

SmokChsr
Who let the magic smoke out?
Premium Member
join:2006-03-17
Saint Augustine, FL

SmokChsr

Premium Member

I don't know about the costs, but there is also "conductive" concrete that is often poured in trenches to create a ground in rock. They use this mostly on mountain tops where it's solid rock. They say it's pretty darn good, though I've never had any experience with it myself. I'm a Florida boy, What's a rock??
49528867 (banned)
join:2010-04-16
Fort Lauderdale, FL

49528867 (banned)

Member

said by SmokChsr:

I'm a Florida boy, What's a rock??

A rock is what you bruise your foot with when younger by steeping on and when older by dropping them.

Though as another Florida boy I must admit excepting the female form, everything else down here is flat as a pancake.

Wayne