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KD6WAG
01-04-2008, 04:43 AM
I know that the best ground rod is one around 8-12 feet in length, buried in the earth. That being said, I can't dig down that deep.

What if instead of installing the ground rod vertically, I actually bury the rod about 1 foot in the earth and lay the rod horizontally?

I believe that for ground rods, depth is not of importance, wheras "area" is key.

Will this work?

KD0BQM
01-04-2008, 04:58 AM
You need to go DOWN with the rod. It should have a pointed end. Just pound it in. You may dig a shallow hole hole to be able to attach the ground wire to it, then cover it up. If the top is "mushroomed" a bit from pounding, just file it smooth so you can slip the clamp over the top to hold the ground wire.

N3MQM
01-04-2008, 04:59 AM
Drive it into the ground with a large hammer

N3MQM
01-04-2008, 04:59 AM
Quote[/b] (KD0BQM @ Jan. 02 2008,22:58)]You need to go DOWN with the rod. It should have a pointed end. Just pound it in. You may dig a shallow hole hole to be able to attach the ground wire to it, then cover it up. If the top is "mushroomed" a bit from pounding, just file it smooth so you can slip the clamp over the top to hold the ground wire.
Almost beat ya http://www.qrz.com/iB_html/non-cgi/emoticons/wink.gif

K7KBN
01-04-2008, 05:03 AM
The effectiveness of a ground rod depends on how undisturbed the earth around it is. If you dig a hole and bury it, it might as well not be touching the earth at all.

Ground rods are supposed to be driven in - as in pounding with heavy tools suitable for installing ground rods (that's how Dave Barry would put it).

Don't confuse ground rods with radials. "Area" isn't a major factor, but soil conductivity typically increases as you go deeper and closer to the water table. Depth is more important.

KC8VLG
01-04-2008, 05:14 AM
Maybe by "dig" he meant he lives on a rock?

K9KJM
01-04-2008, 08:49 AM
Many rental stores will rent out a "Jackhammer" meant to break up concrete and so forth. Those units usually make a great ground rod driver if your soil is really hard.
IF you have something like bedrock near the surface, Using such a jackhammer will allow you to try to drive the rods in many different places until you do find a crack in the rock to drive the rod down in to.
IF you really cannot drive a rod down anywhere, A much better bet is to lay some flat copper strap into a dug trench for much more surface area than any rod. Kind of wasting money to lay a much smaller surface area rod in sideways. Do some research in to ground enhancement materials to put in the trench along with the copper strap.

KD6WAG
01-04-2008, 09:04 AM
Thanks guys for the info, but this leads me to another question... Instead of posting it here, I'll post a brand new question to hopfully get the same response from somebody more knowledgable than me.

W8ATA
01-04-2008, 02:10 PM
Tim,
I checked your location on Google maps and you seem to live in a valley area with significant vegitation. Hopefully that means some soil or non-rock sediment. Not always the case I admit as a lot of the Canadian shield pine forrests grow on shallow soil on granite. I live in a glacial valley with unpredictable rocks below the surface. I use 8', 5/6" diameter copper clad steel rods and drive them with a sledge hammer by hand from a step ladder. I have 6 of them in the ground and all have gone on down to just the tip sticking out. I can tell by the feel when I split a rock or even go through a tree root. Three are at the base of my tower and three right outside the shack. They are spaced about 4" apart. I dug little trenches between each rod in each location and have them bonded together with 3/8" soft copper tubing and acorn nuts over each rod, the tubing being down in the trenches. I have sprinkled copper sulfate crystals over the filled in trenches. It took a while to learn what you hams kept telling me to put good money in antennas, and even longer to learn to put good money in a ground system. Mine is far from the ultimate, but has to be better than my previous single rod. #With a borrowed meter it will soon be measured. I would at least do an 8' test rod and see how it goes down. And as has been mentioned, getting it into an area that hasn't been recently disturbed like digging for a foundation is important.

Good luck and 73,

Russ W8ATA

K9STH
01-04-2008, 03:48 PM
Are you talking about an r.f. ground, a safety ground, or lightning protection ground?

For r.f. grounding anything over 5 feet deep is basically "wasted" since the vast majority (well over 90 percent) is accomplished in the first 5 feet. The effective ground is in a hemisphere around the ground rod with the length of the ground rod being the radius of the hemisphere. Experimentation has shown that by placing multiple ground rods 2.4 times the length of the rods apart gives the maximum ground effect.

That means if you use ground rods 5 feet long then they should be spaced about 12 feet apart. This can be easily accomplished by cutting a 10 foot ground rod (or "hard drawn" copper pipe) in half. If, for some reason, you cannot get 5 feet driven in the ground you can use shorter pieces. If the rod/pipe is cut into 3 pieces (3'4" long) then they need to be driven 8 feet apart. If the rod/pipe is cut into 4 pieces (2'6" long) then they need to be driven 6 feet apart. The geometric pattern can be anything, stright line, square, triangle, diamond, etc.

The rods can be connected together by fairly light guage wire with 14 gauge being a good choice. The wire/braid/flashing to the first ground rod needs to be heavy, but from that point outward you do not need that heavy a lead.

For r.f. grounds a "chemical" type ground rod can be easily constructed.

I do regular presentations on lightning protection and grounding. There are synopsis of my presentations on my website

http://k9sth.com/Page_2.html

as well as some rudementary diagrams. Scroll down to the heading "Grounding Articles" and then choose the link that you are interested.

Now lightning protection grounds are "a horse of a different color". Details for getting good "lightning" grounds are included in the synopsis.

There are definitely several different ways to get good grounds and what I recommend is only one of these. However, what I recommend is usually the cheapest to acquire because it uses readily available material so that you can make the various apparatus required and not purchase them at usually pretty high prices.

My grounding methods have been accepted by a couple of low power television transmitter manufacturers and by the United States Naval War College among others.

Again, you can use several different methods, or even a combination of those methods. I do not claim to have the "only" way of doing things.

Glen, K9STH

KE5FYR
01-04-2008, 04:09 PM
My XYL and I drove an 8 ft rod into soil with intermittent rocks down about 7 ft.
The rod is 5/8 inches in diameter. I have a 1/4 inch drill bit 3 ft long. The 3 ft deep 1/4 inch test hole made it easier (not easy) to drive the rod into the ground. It also lets me test the first 3 ft for rocks the rod might encounter.
You might want to buy or rent a post maul. I had one made by a welding shop. It weighs about 25 lbs but it makes this kind of work a lot easier.
73
KE5FYR and KE5FYS

K8MHZ
01-04-2008, 04:36 PM
'T post drivers' work very well for driving in ground rods and can be purchased at farm implement stores for 20 to 30 dollars.

If you are attempting to make a suitable ground for your AC mains, 2 rods are required, at least 8 feet deep and no closer than 7 feet to each other and bonded by a conductor that is sized to the current rating of your electrical service panel's main breaker.

See section 250 of the NEC for the proper sizing.

01-04-2008, 07:45 PM
There was an article in Rad-Com on this topic.
The author suggested investing in a hammer-drill, of the sort where you can disable the rotary action (drill) but still have it hammer.

Attached to the end of the ground rod, he claims it is almost effortless to drive the full 8' into the ground (+/- boulders, which means withdraw, move a little and try again).

Something I will probably give a try next time I have to install new ground rods.

BTW: for a decent ground, you really need more than one rod, which is what makes this technique so interesting.

K8ERV
01-05-2008, 12:20 AM
Don't lower the rod, raise the earth. (Sorry Jerry).

TOM K8ERV Montrose Colo

KA0GKT
01-06-2008, 09:06 PM
Quote[/b] (K7UF @ Jan. 04 2008,12:45)]There was an article in Rad-Com on this topic.
The author suggested investing in a hammer-drill, of the sort where you can disable the rotary action (drill) but still have it hammer.

Attached to the end of the ground rod, he claims it is almost effortless to drive the full 8' into the ground (+/- boulders, which means withdraw, move a little and try again).

Something I will probably give a try next time I have to install new ground rods.

BTW: for a decent ground, you really need more than one rod, which is what makes this technique so interesting.
There is a special bit made for Bosch and SKS roto-hammers which is specifically designed for driving ground rods. I would guess that you could buy one at Grainger (I haven't looked, just guessing) or places which cater to the professional electric crowd.

That said, the requirment to drive the ground isn't quite true. Several companies provide material which is meant to be used as backfill for ground rods. These Chemical grounds work quite well and are used in broadcast facilities.

One other possibility would be a Ufer Ground (http://www.psihq.com/iread/ufergrnd.htm). In your case it could be a modified Ufer ground, as the metal in the concrete would be the grounding electrode. I would use a piece of copper water pipe. Using a powered post-hole digger to dig an 8'+ hole. Place the copper pipe in the center of the hole and backfill with concrete until you are within 6" of the surface of the earth. Once the concrete cures sufficiently, place an undergound sprinkler valve box over the concrete and the copper pipe which is exposed. From there you may run any grounding circuits underground to the pipe, then either silver solder or exothermically weld the conductor to the pipe for a low ohmic ground. In areas where large stones are present, you may use a rock-drill to get your requisite depth, then bond a solid rod into the hole with hydraulic concrete. (You don't want to use a tube since the hydraulic concrete could well flatten the pipe.)

We were able to get a 4-Ohm ground on top of a mountain using a Ufer ground in the footings of the building and of the tower. There is a wive's tale about lightning "exploding" concrete when the ground is in the portland cement. Don't take that to heart. Ufer grounds were first used in bomb storage buildings near Flagstaff, AZ during WWII, and are commonly used on broadcast and communications towers and on tall buildings.


73 DE KAGKT/7

--Steve

AE1PT
01-07-2008, 01:56 AM
One can also use a 3' section of iron pipe with a cap threaded on the end to get them down far enough to strike with a sledge. Many electricians actually drive them into the ground at a shallow angle to make driving easier.

You should excavate a hole at least 6-9" deep before starting the drive. Afterwards, add water repeatedly to firm up the soil to rod contact. An interesting trick to decrease the ground resistance is to mix a small amount of laundry detergent with the water you pour in. This has a hydrophilic effect that draws moisture to the area that has been saturated. Works for several years until the bond secures itself even more.

KA4EMR
01-10-2008, 08:48 PM
At the feed & seed where I work, I advise electric fence customers to drive the ground rod in a couple of feet, then pull it back out (using a post puller or car jack), fill the hole with water (N4PRT's suggestion of soapy water sounds better), let that soak in and add some more, then reinsert the rod and drive it in as deep as possible. Mud is slippery. Also, if possible, put the rod in a low spot or where it would get rainwater dripping off the barn roof and stay damp, or at least not as dry...

KA0GKT
01-11-2008, 05:25 AM
Quote[/b] (ka4emr @ Jan. 10 2008,13:48)]At the feed & seed where I work, I advise electric fence customers to drive the ground rod in a couple of feet, then pull it back out (using a post puller or car jack), fill the hole with water (N4PRT's suggestion of soapy water sounds better), let that soak in and add some more, then reinsert the rod and drive it in as deep as possible. Mud is slippery. Also, if possible, put the rod in a low spot or where it would get rainwater dripping off the barn roof and stay damp, or at least not as dry...
Use a post-hole-digger to dig an 8'+ hole 6" to 1' in diameter, place the grounding electrode into the center of the hole and backfill with kitty-litter mixed water softener salt leaving 2-3" of the conductor exposed above the kitty-litter mixture but below the surface of the ground.

Cover the exposed end of the grounding electrode with an underground sprinkler valve-box and place a 1-GPH drip irrigation emitterinto the box. Hook this up to your drip irrigation unit. Alternatively, you could run the condensate drain from your central airconditioner or the drain from your swamp cooler or power humidifier into the valve box. This will keep the kitty litter damp and help to leach the salt into the surrounding earth increasing the conductivity of the ground and making the effective diameter of the ground conductor.


73 DE KAGKT/7

--Steve

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