View Full Version : Drivin Groundrods...Bigtime.
11-11-2006, 11:17 PM
here in western NY we don't have a problem. on a multi grounded wye one ground rod is sufficiant. On a delta we use two grounds eight feet apart. One for lightning protection and the other for equipment grounding.In Eastern NY where there's alot of rock they do take ohm readings and drive multible rods in until they get a good ground. In your neck of the woods where the soil is mostly sand I would hope they do the same. its got to be be kinda hard to get a really good ground in florida with the way the soil is but what the hell at least you don't have to put up with the ****ty weather all the time.
11-13-2006, 10:16 AM
We use a contractor to drive rods here. Our part of Michigan is right next to Sleeping Bear Dunes National Lakeshore. As you can imagine, being on a pile of sand does not make for great Ohm readings. We drive to 25 ohms when we can, at every protective device and every transformer or switch location.
This has had a huge impact on the effectiveness of our time curves for fusing.
We had a near miss with a public that I believe was not worse than it was due to grounding. What happened was that a contractor installed a UG in a subdivision and did all the make up. Somehow one transformer the concentric was not bonded to a transformer lug. Well this developer was going around with a weed wacker. He set the weed wacker on the transformer to change the line. When he picked it up he got a shock. Our line crew opened the padmount and found that the current was burning the fiberglass pad on the inside of the enclosure. The transformer had been grounded and I believe that this protected the developer.
11-13-2006, 11:19 AM
We have tested and driven rods for all OCR poles and all gang switches. But we have not done it for every pole. We also test on most new transformers and drive rods to a max of four rods. If it needs more than four its sent back to engineering.
11-16-2006, 08:39 PM
Back in the early '70's we had a one man "crew" who's job was to drive groundrods in a grid at any equipment installation ie;GOAB's,OCR's;etc..These rods were only 4',with threaded ends,so he could keep adding to them until he got as close to 'o'ohms as possible.They were also spaced a certain distance apart and connected together by a calweld connection- I think,-It's been a while.He drove the rods with a small jackhammer.That's about all I remember on this.This all took place around Alexanderia Va,Washington DC area. :o Loadbreak
11-19-2006, 10:35 AM
Here in Eastern Canada, We use a pole ground in distrubution, like a mosiquito coil attached to the butt. On transmission we use 3 ground rods in a radial line 10' apart.
12-12-2006, 12:46 AM
I didn't read that when anyone was putting in grnds if they just throw the rod in the pole hole or put it 3ft out in undisturbed soil?
12-12-2006, 02:19 PM
We go 3 feet out from the pole and about 1 1/2 feet fron UG enclosures. I can't remember the last time we drove less than 4 rods to achieve the ohm reading we desired. We also mark each pole and enclosure with an RD to let everyone know of the driven ground.
12-14-2006, 11:44 PM
I've only ohmed a grnd once when I was an app. and it was for stray voltage. We only put in 4 per mile not including banks and inside u/g enclosures. One for single phase,2 for 3 phase and 4 in switchgear. We seem to do ok I think its a money thing.
12-17-2006, 05:51 PM
I can state that for certain equipment, grounding is paramount!
My example is a cap bank.
I received a "pole on fire " call one day, and arrived to find a cap bank pole that had a huge arc going to ground around the pole, very exciting.
I had the dispatcher drop the feeder and opened the fuses.
When we got the feeder up, I was looking around and saw that the pole bond to neutral jumper was broken!
Obviously, the crew that set this pole had not driven enough ground rods , and the system neutral was compensating. Once the neut/ground jumper failed, the lack of proper grounding became an issue, including a big public safety issue.
It may seem mundane, but you better believe that proper grounding is absolutely mandatory.
Proper grounding saves equipment, and more importantly can save lives.
Just my 2 cents.....
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