Call Search
     

New to Ham Radio?
My Profile

Community
Articles
Forums
News
Reviews
Friends Remembered
Strays
Survey Question

Operating
Contesting
DX Cluster Spots
Propagation

Resources
Calendar
Classifieds
Ham Exams
Ham Links
List Archives
News Articles
Product Reviews
QSL Managers

Site Info
eHam Help (FAQ)
Support the site
The eHam Team
Advertising Info
Vision Statement
About eHam.net

   Home   Help Search  
Pages: [1] 2 Next   Go Down
  Print  
Author Topic: Questions about grounding stake vs cold water pipe.  (Read 13415 times)
W9KDX
Member

Posts: 770




Ignore
« on: August 22, 2011, 05:33:11 AM »

My antenna set up will be much easier if I ground the antennas to a cold water pipe along with the equipment.  Is there any problem with this as opposed to grounding the antennas (straight wire) outside with a stake in the ground?

Thanks,

Sam
Logged

Sam
W9KDX
KL3HY
Member

Posts: 117




Ignore
« Reply #1 on: August 22, 2011, 08:24:11 AM »

Have you verified that your water line coming off the main is copper pipe?
Logged
AA4PB
Member

Posts: 12832




Ignore
« Reply #2 on: August 22, 2011, 08:45:38 AM »

If you are talking about grounding for lightning protection then you should ground directly to ground rods outside the building. The idea is that you don't want lightning currents flowing through the house on their way to ground.

In the U.S., the ground rods must be bonded (permanently connected to) the electrical service ground which will in turn be bonded to any conductive water pipes in the house for safety reasons. Still the current path from you antenna feed lines to your ground rod(s) is external to the house.
Logged
W9KDX
Member

Posts: 770




Ignore
« Reply #3 on: August 22, 2011, 09:35:00 AM »

Thanks, I was afraid of that, and yes the water pipe is copper and grounded.  Unfortunately, all the affordable grounding hardware costs less if I ground inside the house, and of course, the existing electrical outside ground rod is on the wrong side of the house.  I was hoping to save some but I guess not.  No point messing with lightning.

Sam
Logged

Sam
W9KDX
K9KJM
Member

Posts: 2415




Ignore
« Reply #4 on: August 22, 2011, 11:47:47 PM »

AA4PB is correct. You must ground to an external ground rod first, Then bond to your copper water pipe (And other grounds- CATV, Telco, Power, etc)
It does not have to cost a lot.  Discount home supply stores sell heavy copperclad 8 foot ground rods for about 10 bucks, And if you are careful to not kink it, Some soft copper tube from the same home supply store can be used as the ground conductor instead of expensive heavy copper wire. 

For more tips on how to do it properly on a low budget:
http://www.scribd.com/doc/14868226/lightning-protectiontaming-thors-thunderon-a-budget

Logged
K0JEG
Member

Posts: 658




Ignore
« Reply #5 on: August 23, 2011, 07:00:00 AM »

Off topic, but reminds me of one of my favorite photo galleries:

http://www.kramerfirm.com/pictures/thumbnails.php?album=8

If you recognize your house in any of these pictures, call your cable company and raise hell (maybe from a neighbor's house!).
Logged
KB1TXK
Member

Posts: 441


WWW

Ignore
« Reply #6 on: August 23, 2011, 07:22:56 AM »

http://www.kramerfirm.com/pictures/displayimage.php?album=8&pos=83



Just......wow.
Logged

W6RMK
Member

Posts: 651




Ignore
« Reply #7 on: August 23, 2011, 07:26:49 AM »

Lots of interesting advice here.
1) what is your building's main electrical service ground?  Everything has to tie to there, so you need to know, whatever you do.
2) The pipe may be copper, but is it continuous from where you are to where it's connected to the grounding system, if at all?  Will it ALWAYS be continuous (what if someone fixes it and puts in a insulating section).  Is it even connected to the building ground (For example, my house, built in 1998, does NOT have the plumbing bonded to the service ground, which is a Ufer/Concrete Encased Grounding Electrode, on the other side from where the water line comes in.)  In general, using your plumbing as a protective lightning ground isn't recommended.
3) You may or may not care if you're code compliant: if you do care: rods have to have 8 feet in contact with the soil, so a typical 8 foot rod from the home improvement store won't usually do.  They're also often not large enough in diameter to meet code.  Why do they sell them?  Who knows.. people buy them)
4) I'd find it hard to believe that copper tubing would be cheaper than the copper wire needed to bond your ground rod to the system ground.  There are pricing anomalies (the tubing was manufactured and wholesaled when copper prices were lower, for instance).  
5) the code looks for AWG 6 or larger for bonding jumpers in connection with antenna systems  (see various Art 800 sections).  (if your house has 100A service or AWG2 feeders, it might be wired with AWG 8 bonding, but that doesn't work for the antenna stuff.  Who ever claimed the code was entirely self consistent?)

6) Size of conductors for lightning protection (NFPA780) can vary substantially from that required for electrical safety grounds (NEC).  bear in mind that AWG10 can take a big 100kA lightning strike without melting: the requirements on sizing have more to do with mechanical toughness.
Logged
KB9CRY
Member

Posts: 4283


WWW

Ignore
« Reply #8 on: August 23, 2011, 07:18:30 PM »

My antenna set up will be much easier if I ground the antennas to a cold water pipe along with the equipment.  Is there any problem with this as opposed to grounding the antennas (straight wire) outside with a stake in the ground?

Thanks,

Sam


NEC dictates that one grounds to a real live ground rod.  Do it the right way, not the easy way.
Logged
K1CJS
Member

Posts: 6034




Ignore
« Reply #9 on: August 24, 2011, 04:42:00 AM »

My antenna set up will be much easier if I ground the antennas to a cold water pipe along with the equipment.  Is there any problem with this as opposed to grounding the antennas (straight wire) outside with a stake in the ground?

The easy way usually isn't the right way.  In this case it's definitely not the right way.  The antenna ground should always be a ground rod as close to the point where the antenna coax comes into the shack/house that is practical.  That ground point has to be bonded to the electrical service ground rod.  That is where you can use the cold water pipes--IF--there is a ground connection from those pipes to the service ground rod already, AND if the local code doesn't prohibit it.

In older homes, there is almost always that connection.  AAMOF, some older installations used the incoming water pipe AS the service ground point.  Since the useage of PVC pipe for the incoming water supply line has become common, that grounding method has been discontinued, but there are still plenty of houses out there that use it.

However, the best bonding method is running a number six copper conductor from your antenna ground rod to your service ground rod, and that is the method that should be used--unless you can bring your coax cables into your house within a few feet of the electrical service ground point.  If you can do that, just use the electrical service ground point for your antenna ground connection.
Logged
W6RMK
Member

Posts: 651




Ignore
« Reply #10 on: August 24, 2011, 08:40:53 PM »


In older homes, there is almost always that connection.  AAMOF, some older installations used the incoming water pipe AS the service ground point.  Since the useage of PVC pipe for the incoming water supply line has become common, that grounding method has been discontinued, but there are still plenty of houses out there that use it.



ran across an interesting aspect of using the piping the other day.  I don't know about the electrical implications, but they had done a partial copper repipe of a house originally plumbed mostly in iron pipe. (hey, at least it's not lead pipe).. In order to reduce corrosion on the remaining pipe, there were CPVC (hot water approved plastic) fittings between the segments.  House was originally built in the late 60s, early 70s, judging from the tract, and probably also had "pipe in slab" in places (which probably leaked and had been replaced in sections, going up the wall and into the attic and back down).



Logged
K1CJS
Member

Posts: 6034




Ignore
« Reply #11 on: August 25, 2011, 04:31:51 AM »

....I don't know about the electrical implications, but they had done a partial copper repipe of a house originally plumbed mostly in iron pipe. (hey, at least it's not lead pipe).. In order to reduce corrosion on the remaining pipe, there were CPVC (hot water approved plastic) fittings between the segments....

Thanks for pointing this out.  I neglected to say that you MUST make sure of the continuity of the copper piping so that the bonding of the two ground rods is assured.

Quote
House was originally built in the late 60s, early 70s, judging from the tract, and probably also had "pipe in slab" in places (which probably leaked and had been replaced in sections, going up the wall and into the attic and back down).

Iron pipes included--and the house was built in the 60s/70s?  Are you sure those were water supply pipes and not hot water heating pipes?  Copper tubing use for water supply was more or less standard practice in the fifties, never mind the 60s/70s.  I doubt that there was iron pipe water supply lines in place unless the house was added on to, and the original house was early 1900s vintage.
Logged
AA4PB
Member

Posts: 12832




Ignore
« Reply #12 on: August 25, 2011, 05:30:37 AM »

In most places the code requires jumpers around plastic couplings so that the metal pipe sections remain electrically bonded together. You should check it out however because the code isn't always followed.

This is primarily a personal safety issue. Consider the worst case scenario where one isolated segment gets shorted to the electrical hot line somewhere. In your bathroom sink the drain is at ground potential but the faucet is at 120VAC. Not good if you become the path between the two while washing your hands.
Logged
W6RMK
Member

Posts: 651




Ignore
« Reply #13 on: August 25, 2011, 10:02:49 PM »

sure, the code requires it, but hey, when Bob gets his brother in law's second best friend to do a quick plumbing job over the weekend, they might not do all the things they should.

With respect to iron water pipe in a 60s vintage house. Who knows why it is the way it is.  That particular tract was notorious for strange things that were rumored to have occurred during construction (e.g. rebar gets inspected, then moved to the next lot, quick, before the concrete pour the next morning)
Logged
K1CJS
Member

Posts: 6034




Ignore
« Reply #14 on: August 26, 2011, 04:36:55 AM »

Yeah, I know what you mean.  Some unscrupulous contractors have been known to pull fast ones like that.  That's one of the reasons for having a home inspection done before purchasing a home.
Logged
Pages: [1] 2 Next   Go Up
  Print  
 
Jump to:  

Powered by MySQL Powered by PHP Powered by SMF 1.1.11 | SMF © 2006-2009, Simple Machines LLC Valid XHTML 1.0! Valid CSS!