Re: LOOKING FOR INFORMED OPINION ON STATION GROUNDING PROCEDURE(S)


Don Wilhelm <w3fpr@...>
 

Phil,

First you should physically verify that the wire is indeed connected to the utility ground wire outside.� If it is, then you can use it to connect your shack ground.� The utility ground wire should connect to its own driven ground rod located as close to the electrical entry box as possible.

I think you are misinterpreting that NEC prohibition against using a cold water pipe as a ground.� There were times in the past when a cold water pipe was used as the *only* ground point in a house.
If that heavy wire connects between your cold water pipe *and* the utility entry ground rod, then you are OK, but if that cold water pipe connection is the *only* ground connection for the utility ground, then that is not a good thing and should be corrected.

If you cannot easily determine that you have an existing ground rod at your utility entrance, you could "play it safe" and drive a new ground rod at the utility entry point and connect the existing ground wire to that new rod.� If you want to comply with new grounding rules, drive another ground rod 6 feet away from the first and connect the 2 ground rods together with #4 wire (#6 qualifies as sufficient, but #4 is better).� The ground wire and the ground rods can be buried, in fact most inspectors prefer that they be buried because there is then a smaller chance that the ground wire could be cut with a lawn mower or weed cutting device.

If you are looking to that ground connection for lightning protection from your antennas, then that 160 mil wire is not adequate for the job (it is adequate for AC safety ground).� For lightning protection, run 2 or 3 inch wide copper strap to the outside ground rod and do not use any sharp bends - lightning likes to travel in a straight line.

An even better protection for lightning is to run a perimeter wire around your house (#6 or larger wire) with a driven ground rod at each point where the wire makes greater than a 45 degree turn - it only needs to be 6 inches to a foot deep.� That perimeter wire should also connect to the Utility Ground Rod (all ground rods must be interconnected for safety).� That perimeter wire will help keep a lightning surge traveling through the earth from punching a hole in your foundation.

73,
Don W3FPR

On 1/8/2015 5:27 PM, Phil Anderson aldenmcduffie@... [4sqrp] wrote:
�

Hey guys,

Getting ready to sheet rock my shack in the basement - to keep it warmer - and pondering how best to provide a safety ground, i.e. electrical ground. Of course, want to wire the ground before adding the rock, hi.

I am assuming the right way is to run a separate (but costly) large copper wire, 160 mil diameter from the earth ground connection at the main electrical box or secondary box (have one of those too) to my station location. Dr. Murphy (of Murphy's Law) of course saw to it that my station is at the other end of the house! Hi.

Then, I noticed that there is a 160 mil (big copper) wire running along a 2x4 header in the basement ceiling to the intake of my water line half way of the basement wall, secured with a ground clamp (which ACE hardware sells too). Hm. Perhaps I could run that remaining ten feet to my bench? I measured the resistance from the bare wire ground on a basement outlet to the water pipe and it is about 3 ohms. So for sure the cold water pipe is connected to my main box ground, likely directly.

However ("There is always an however," Mr Murphy says) the national electrical code - via a google search says DO NOT use a cold water pipe connection for the earth ground in a three prong socket replacement for a two prong socket (1950 era slang). I remember those.

Hm? Unc Phil in cold Lawrence, KS/W0XI


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