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Author Topic: Station and Antenna Grounding  (Read 7104 times)
KD8HIO
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« on: January 07, 2011, 05:47:43 AM »

I have recently started building my station in my basement in a Condo.  I have pounded 2 8' grounding rods in, on right below my two band (2M/70cm) Homebrew Pole and one about six feat away next to where my feedlines enter the house.  Now the questions.

1) I have grounded my Pole to the  rod below it and I have connected the two ground rods together but I have not as yet connected then to the electrical ground because the actual ground point for the electrical ground is on the other side of the house.  Can I use the existing copper water pipes to complete that ground or should I run a wire between the two grounding post to complete the ground connections to ensure that my ground are all unified.

2, the J'pole sits 10 feet above ground; do I need radials to complete a ground place and if so how do I figure the size and quantity?

73,
Rick
 
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KB9CRY
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« Reply #1 on: January 07, 2011, 10:43:58 AM »

I have recently started building my station in my basement in a Condo.  I have pounded 2 8' grounding rods in, on right below my two band (2M/70cm) Homebrew Pole and one about six feat away next to where my feedlines enter the house.  Now the questions.

1) I have grounded my Pole to the  rod below it and I have connected the two ground rods together but I have not as yet connected then to the electrical ground because the actual ground point for the electrical ground is on the other side of the house.  Can I use the existing copper water pipes to complete that ground or should I run a wire between the two grounding post to complete the ground connections to ensure that my ground are all unified.

Connect them with a wire via an outdoor path.

2, the J'pole sits 10 feet above ground; do I need radials to complete a ground place and if so how do I figure the size and quantity?

73,
Rick
 
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WX7G
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« Reply #2 on: January 07, 2011, 05:00:09 PM »

Radials will not be required for the J-pole.
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K9KJM
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« Reply #3 on: January 07, 2011, 10:48:29 PM »

The prefered method of bonding your ground systems together is with a good size conductor outside the building, Buried a few inches so no one trips over it, And add ground rods along it's length, (Ground rods should be spaced about twice the distance apart as the depth- Space 8 foot deep rods at least 16 or more feet apart)
The conductor should really be #6 gauge copper wire, Or heavier. A very good low cost conductor can be soft copper tube you buy in rolls. Some 1/4" copper tube will conduct almost as good as #2 copper wire!  (You do have to be careful to not kink the copper tube!)
All that being said, Yes, You could use the copper plumbing to bond the grounds also.  I would follow the plumbings entire path to make sure there is nothing plumbed in that could be a poor conductor. If there were, That item should be "jumpered" around with some flat copper strap.  Small stainless steel heater hose size hose clamps from any auto parts store work well to bond copper strap with copper pipe.
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N7TEE
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« Reply #4 on: February 24, 2011, 08:54:15 AM »

Rick,

Have you ever seen what electricy can do to a cooper pipe?  You do not want to use a stainless steel clamp around your water pipe, as you may one morning go down to a swimming pool in the basement.  They make a cooper strap for the pipe.  Then you have to see if the pipe goes all the way to the water meter outside.  The pipe should be the last resort for grounding.

Dave
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WX7G
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« Reply #5 on: February 24, 2011, 08:27:54 PM »

What is this cooper of which you speak?
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W6RMK
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« Reply #6 on: February 25, 2011, 10:01:41 AM »

First question you need to answer for yourself.. Do you care about electrical code compliance?  (If so, then you need to check the local codes..)..

Second.. google/bing for the Mike Holt Low Voltage Handbook... it's a free download from Mike Holt's site (he's a guru of electrical code and does training, etc.)... it will answer a LOT of questions about the rules and has good explanations.  Last I checked, it hadn't been revised in a few years, but this kind of thing is basic.  If you need code compliance, then check to make sure something hasn't changed.

The code requires that all grounds be bonded together. (NEC art 250 is all about grounding and describes in excruciating detail the requirements of how to do it.. In particular 250.64, 250.66 are sections to look at)

However, regardless of whether code compliance is an issue, you do NOT want to use interior plumbing as a grounding conductor.  (the code doesn't allow it, because it's a bad idea).. It might not be continuous, for one thing. You don't want voltage from fault currents on faucets, for another.

The code requirement (and a good idea) is to run a continuous (no splices) bonding jumper from your local ground rod to the system ground point (at the entrance panel). The size of the conductor depends on where it's installed (underground, above ground, in conduit, or not)..  AWG 6 works for "attached to the side of the building outside", otherwise outdoors needs AWG 4. Indoors, you could run a smaller conductor: the code requirement is basically that the bonding conductor has to be no smaller than the branch circuit wires, AWG14 or AWG12 in most residential construction.. the idea is that in the event of a line/ground short, the grounding conductor can carry the full branch circuit current without melting or getting too hot (so the breaker can trip and do its job).

there are good reasons (not code related) to run the bonding jumper outside.  If a fault from an overhead power line occurs, you want the fault current running OUTSIDE the house.  Ditto for induced currents from lightning.

If you're going to be code compliant, there's all sorts of rules about how the wires need to be connected to the rods (exothermic welding or listed compression connectors), how deep the rods have to be, etc., etc.   But many hams don't worry about this kind of thing:  just like the code require that wire antennas be Copper Clad Steel (Copperweld(r)) of a particular size.  the usual thing is to look at the rules, understand WHY the rule exists, and make intelligent choices.  Usually, something winds up in the code because something bad happened in the past, but that "bad thing" may be impossible or really unlikely in your situation, so you can do something else and still be safe, which is the whole idea, right?

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K1CJS
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« Reply #7 on: February 26, 2011, 08:24:10 AM »

I have recently started building my station in my basement in a Condo.  I have pounded 2 8' grounding rods in, on right below my two band (2M/70cm) Homebrew Pole and one about six feat away next to where my feedlines enter the house.  Now the questions.

1) I have grounded my Pole to the  rod below it and I have connected the two ground rods together but I have not as yet connected then to the electrical ground because the actual ground point for the electrical ground is on the other side of the house.  Can I use the existing copper water pipes to complete that ground or should I run a wire between the two grounding post to complete the ground connections to ensure that my ground are all unified.  

If the house electrical system already uses the cold water pipes for ground, yes, you can just connect to them.  The idea is to equalize the potential of the different grounds.  If the electrical system does NOT connect to the cold water pipe, however, you should run a separate ground to it, outside the house.  In some areas, using the water system for grounding is frowned on.
 
Quote
2, the J'pole sits 10 feet above ground; do I need radials to complete a ground place and if so how do I figure the size and quantity?


As someone else already said, j-poles don't have any need for radials.
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W6RMK
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« Reply #8 on: February 26, 2011, 03:06:09 PM »

No,no,no

You cannot use your water pipes to connect ground rods.  That is, you can't use it as a grounding conductor, which is what k1cjs is suggesting.  It is unsafe, because you don't want fault currents flowing through the pipes.

You can use the water pipe as one ground "rod", although most places these days don't allow it to be the only ground.  Too much plastic pipe and deliberate electrical breaks to prevent corrosion.

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K1CJS
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« Reply #9 on: February 27, 2011, 08:49:41 PM »

No,no,no

You cannot use your water pipes to connect ground rods.  That is, you can't use it as a grounding conductor, which is what k1cjs is suggesting.  It is unsafe, because you don't want fault currents flowing through the pipes.

You can use the water pipe as one ground "rod", although most places these days don't allow it to be the only ground.  Too much plastic pipe and deliberate electrical breaks to prevent corrosion.



Jim, you obviously have not seen too much of the older homes--and even the newer ones.  I suggest you look at some of the washing machines and dishwashers that are still in use.  The cold water connections were purposefully made WITH A GROUNDING CLIP ON THEM TO GROUND THE MACHINE!  Also, if you notice, I said "If the house electrical system already uses the cold water pipes for ground, yes, you can just connect to them."  Then, I also said "If the electrical system does NOT connect to the cold water pipe, however, you should run a separate ground to it, outside the house.  In some areas, using the water system for grounding is frowned on."

Bottom line is that grounding systems vary.  It IS perfectly safe to use the cold water system for grounding IF IT IS ALREADY USED FOR THAT PURPOSE. 

Please, next time read the entire post BEFORE making your comments.
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W6RMK
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« Reply #10 on: March 05, 2011, 05:09:44 PM »

I did read your post, and I will stand by my statement: practices that were ok 30-40 years ago are not ok now.

That thing with the grounding clip (and I'll bet you don't see many of them today" was back when they would wire dryer receptacles without a grounding conductors (just like the rest of the receptacles in your house, before the advent of the "third prong").  Back in the day, 110V appliances at least had the "neutral", but 220V appliances like a dryer had two hots, and like the washer it's used in a place with water and higher shock hazard, so a ground was needed.  Hence, the separate ground wire.  (Which I, as a toddler, shoved into the hot terminal on the receptacle, the resulting flash, bang, and scorch marks guaranteeing that I'd wind up earning a living as a EE)


Home appliances, especially ones that are quasi permanently installed: stoves, ovens, washers, dryers, have always been a sort of special case when it came to grounding.  There's also a recognition that these things have long life times, so there are provisions in the code to accommodate that.  (although the code generally doesn't say much about appliance design.. the "boundary line" for the scope of the code is the wall receptacle, for the most part)


Using the plumbing system to carry fault currents from a line/chassis short or similar is a really bad idea.  That's what the "green wire ground" is for. Using it to carry RF currents is probably not such a hot idea from RFI/EMI/EMC, but most likely that would just be annoying.  Having lightning or external fault currents (for the original poster's antenna) carried through your plumbing is a really bad idea.
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K1CJS
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« Reply #11 on: March 19, 2011, 07:19:09 PM »

Your concerns are valid if--and that is IF--the cold water piping has plastic in it.  If it does not, your concerns are meaningless.  I stand by my original post--and the caveats I spelled out then.
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K9KJM
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« Reply #12 on: March 19, 2011, 09:22:32 PM »

All that being said, Yes, You could use the copper plumbing to bond the grounds also.  I would follow the plumbings entire path to make sure there is nothing plumbed in that could be a poor conductor. If there were, That item should be "jumpered" around with some flat copper strap.  Small stainless steel heater hose size hose clamps from any auto parts store work well to bond copper strap with copper pipe.
Yep, I agree.  As I also pointed out in an earlier post above.
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KD8MJR
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« Reply #13 on: March 31, 2011, 03:53:06 PM »

Listen to W6RMK..
You have no idea how well those cold water pipes are grounded and if you should use them and lightning strikes you or another family member taking a shower or washing the dishes may be instantly killed.
It's just a crazy idea that only sounds appealing because it's easy to do.
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K1CJS
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« Reply #14 on: April 05, 2011, 06:51:29 PM »

MJR--YOU may consider it a crazy idea, but it was--and still is--code in some areas.  The cold water pipe system had to be connected the panel ground to PREVENT accidents like you describe from happening.

And please, look and read before you start throwing rocks.  As I told RMK, the use of the cold water pipe system is dependent on whether it is being used NOW as a grounding system.  If it isn't, then you should not connect to it.  If you look at my post, THAT IS WHAT I SAID IN THE FIRST PLACE!
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