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Author Topic: Equipotential for Grounds - Connection in Soil  (Read 762 times)
K5RFF
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« on: December 06, 2008, 08:56:21 PM »

I want to connect the ground rod located immediately outside my shack window to the buried copper water pipe which is the ground for the house wiring system located abotu 15 feet away.  The problem is that the water pipe is buried about 3 feet deep.  I could dig a hole, expose the copper pipe, attach a clamp-on connection, then bring some type of wire up out of the ground and connect it the ground rod located near my shack window.  

If I were to instead use an exposed water pipe inside the house it would involve routing wire though walls and the attic, and I would like to avoid this.

A connection in soil I am sure is very problematic.

Has anyone tried this with success?  What parts and types of wire was used?  I suppose I would need to dig the buried connection up every few years to be sure it is still in place and not corroded away.

If this was a good idea I would see it everywhere - but I don't.  So maybe not a good idea.

Thanks.  73, de K5RFF
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K9KJM
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« Reply #1 on: December 07, 2008, 01:05:11 AM »

If your copper water pipe is only about 3 feet down, I would just dig down to it and attach your ground wire to it.

Use only copper wire, And I would use something like a few stainless steel hose clamps to clamp the wire to the pipe. Use lots of anti ox compound on the connection and there should be no problems.

Your bonding wire needs to be at least #6 or heavier copper wire, Or even better, flat copper strap.

(You can buy a 10 foot long roll of six inch wide .026" thick copper roof flashing at most any well equipped home supply store for under 30 bucks, Cut it into three 2 inch wide strips with a tin snips and you will have 30 feet of nice grounding strap.)


Here in northern Wisconsin with deep freeze conditions, Pipes are buried LOTS deeper than 3 feet so digging down to them is not so appealing......
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KB9CRY
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« Reply #2 on: December 07, 2008, 01:27:43 AM »

Ditto what he said.
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K5RFF
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« Reply #3 on: December 07, 2008, 12:39:42 PM »

Thanks for reply.

I do request a clarification on the type and size of wire used for the purpose of creating equipotential between grounding systems.

Note that the house electrical system uses buried copper water supply pipe as its ground system.

My shack has a ground rod located just outside the shack as its ground system.  

I want to interconnect the two grounds for the purpose of creating equipotential.

My first question is do I want a small capacity wire or a large capacity wire for the purpose of creating equipotential?

If the house ground system is called upon to discharge current, I don't want that current coming into my shack.  Conversely, if the shack ground system is called upon to discharge current, I don't want that current coming into my house.

Given my concern for where the current goes, should we not encourage the current to go into other ground systems?  Perhaps we can prevent current from going into other ground systems by making the interconnecting wire relatively small compared to the ground systems, or even fused?

Thanks. 73, de K5RFF
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KB9CRY
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« Reply #4 on: December 07, 2008, 01:28:49 PM »

Given my concern for where the current goes, should we not encourage the current to go into other ground systems?

Yes you should spread the strike energy current into as many grounds as possible.

Perhaps we can prevent current from going into other ground systems by making the interconnecting wire relatively small compared to the ground systems, or even fused?

Yes that would do it but you WANT the current to go into other ground systems.  It will not go into your house, the strike energy wants to go to ground in a really big way.  It will not go into your house.

Another VERY IMPORTANT thing:

You need, really really need, in a very extremely big way, to also bond your ground rod to your electrical service entrance ground rod.  A lot more so than bonding to the copper water pipe.  Do a search on Grounding in the main forums search box to find tons of discussion on the subject.
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K5RFF
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« Reply #5 on: December 07, 2008, 01:46:47 PM »

Thanks for reply.

My house does NOT have a ground rod at the electrical service entrance.

Maybe this was not required by code in the early 1970's when my house was built.

In my garage there is a bare copper wire that spans from the electrical panel to the cold water pipe located and exposed in the hot water heater cabinet, both in my garage.

Thanks.  73, de K5RFF
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W3LK
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« Reply #6 on: December 07, 2008, 05:46:40 PM »

<< My house does NOT have a ground rod at the electrical service entrance.

Maybe this was not required by code in the early 1970's when my house was built.

In my garage there is a bare copper wire that spans from the electrical panel to the cold water pipe located and exposed in the hot water heater cabinet, both in my garage.  >>

I'd be surprised if it wasn't in the code - just ignored by some inspector. I've seen it happen more than once.

I would call your electric utility company and request that they bring the grounding up to code. I would not be comfortable with only a wire run across the garage to a water heater closet.

73,

Lon - W3LK
Naugatuck, Connecticut
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A smoking section in a restaurant makes as much sense as a peeing section in a swimming pool.
K9KJM
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« Reply #7 on: December 07, 2008, 07:10:28 PM »

Again, Wide flat copper strap, The wider the better is the best conductor to use.  If using wire, At least #6 gauge OR HEAVIER wire.  Bare copper.

For some good info:

http://members.cox.net/pc-usa/station/ground3.htm

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N1QOQ
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« Reply #8 on: December 12, 2008, 08:10:11 PM »

I'm willing to bet it is the home owners responsibility to maintain the grounding system.
It is very easy to update your service grounds.

1. Install two 5/8" x 8'  ground rods a MINIMUM of six feet apart( the further apart the lower the resistance-this is a good thing). Drive the rods a full 8'. Use a minimum of #6 copper to run between the rods and back into your electric service panel. Use "Acorn" type clamps to connect to the rods. Not hose clamps or duct tape. Connect your new ground rod wire to the ground bar of your panel.

2. Locate and inspect the ground clamp going to your water main. If it is corroded or broken replace it with the proper clamp. Use some fine emory cloth to clean up the pipe.

3. Bond all of your lightining protection to your new ground rods as well.

4. If you have gas piping in your home it is also required to be bonded. #6 and a water pipe clamp is fine. It can be a jumper from a cold water pipe.

 73 Paul
 
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K3AN
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« Reply #9 on: December 14, 2008, 05:40:27 PM »

Whoa, unless you're an electrician and you KNOW the NEC and local code requirements, you should have a licensed electrician do that work. You might even be able to get the power company to do it. Call them and ask the innocent question, "How come there's no ground rod where the electric service comes into my house?" Remember that everything up to and including the meter is their responsibility.
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N1QOQ
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« Reply #10 on: December 14, 2008, 05:59:17 PM »

 It is the customers responsibility to ground the electric service in the house. Grounding a service is not a big mystery. The method I posted is correct as per the current NEC, and will pass any inspection. Of course if you are not comfortable doing the work by all means have a LICENSED professional do it. -73 Paul
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