On 9/6/2018 5:46 AM, Gareth's Downstairs Computer wrote:
Unearthed the previous fan of plumbers' copper microbore tubes
and associated ground rod to find a corroded and non conductive
mess and raised the question of how to protect underground
junctions from the worst that nature could throw at them?

Firstly, resurrecting a technique from school metalwork lessons
from 53 years ago when brazing things together, dig out the
gas torch, soldering flux***** and solder and connect all together
electrically.

Secondly, to protect the now-relatively-massive joint, smear with
petroleum grease. Was this a good idea, and is there something better?

***** Curious as to whether could be combined with one's radio
interest to nake a flux capacitor to go time travellingg :-)



I don't know how to protect it, I recently installed ground rods and
figure to periodically test them and replace as needed.
I ran a 253ft BOG antenna, I needed a ground at each end.
I started with 1-five ft 1/2" copper pipe, with predrilled 1/8" hole
running down and around the pipe. I used the method on page 25 of this
pdf to measure the ground resistance.
http://www.weschler.com/_upload/site...owntoearth.pdf

I had a pair of wires ran from my home to each end of my BOG antenna
so it was convenient to connect it to a variac driven by an isolation
transformer. I used that as my voltage source*. I set it at about 40V,
but measured the voltage at the ground rods for calculations, because
of the voltage drop of the feed wire.
My first measurement was 112 ohms, both ends 253 apart were basically
the same even though I had 3 rods at one end and 1 rod at the other. I
added 2.5lbs of Calcium Chloride at one end by pouring the water/Calcium
Chloride solution into the three copper pipe ground rods. After a few
hours a retest showed a drop from 112ohms to 73 ohms. The next day it
was down to 60 ohms. About a week later I added another 3.5lbs of the
Calcium Chloride solution into the copper pipes, this brought the
resistance down to 34 ohms.
I added 2 more rods to the other end and added more Calcium Chloride,
that brought the end down to 24 ohms.
The measurement at one end 22.35V and 660ma for 33.9 ohms.
The other end 13.14v and 580ma for 23.9 ohms. Lower voltage because my
240ft feed line was a much smaller gauge and had more voltage drop.

* I know 60hz drive voltage is not ideal but, I didn't have a signal
generator with enough power do the job.
http://www.esgroundingsolutions.com/...stance-meters/

There are some papers saying DC better to measure earth ground, I
don't know.