Allow me:
Yes I have. But that was when I was in the Air Force and doing grounding for each transmitter of a McCullough loop Fire Alarm street box system. I had finished only the housing portion of the base in rocky New York soil and had driven dozens of them with some stacked 4 deep to get each transmitter to successfully transmit via ground return. I was dammed glad that the truck I was provided with had a hydraulic drilling motor and I had been provided with drill bits for the rods.
As I had been on the detail for weeks at that point I started reading the manuals for the system. The wording "The resistance of the central station grounding is critical to the performance of the system during a break in one of the alarm receiving loops" leapt out at me. Come the next day I asked the senior NCO to show me how the ground resistance tester worked so I could confirm the resistance to ground at each box prior to driving additional rods.
He asked me to put it on the schedule and I asked if I set the meter up using the central station grounding as the tested ground would he take a quick look at it to see if I had done it correctly. He did and the measurement we got surprised him a lot! The central station grounding was dammed near non existent. I showed him the diagram of the central station grounding which was laid out in the manufacturers manual and he authorized me to build it.
Engineers were called in to check the work prior to back fill and when they saw the remnants of the previous system they researched what might have happened to it. They took soil samples and the answer became clear. The residues from spilled aircraft fuel had turned into a fairly potent acid when the rain mixed with them and the system had dissolved in the resultant underground acid bath.
Part of that happening was that the system had originally been built during World War 2 and consisted entirely of steel because copper was simply unavailable for that use. The engineers had a drain installed at the edge of the concrete which made up the flight line so that no fuel would ever escape the pad again. They had me do all of the back filling except the last foot with some sort of conductive soil.
It came in 100 pound bags and it took me days to pour it into the trench that went clear around the building. I later learned, while training to be an electrician, that the manufacturers diagram showed a Ground Ring with 2 stacked driven rods every 20 feet. I even found the old attachment points for the reinforcing steel in the floor and since it was in that diagram I took a wire brush on a drill to them and tied them in as well.
Funny thing was the diagram diagram didn't call for Cad Welding. All of the connections were made with buriable mechanical connections. Upshot was that not one additional street box transmitter needed additional grounding to successfully transmit via Ground Return. The Sgt said thanks for the work and sent me back to my detail in power production shop with a very nice evaluation.
