Driving Ground Rods with Water, CPM, GEOS, GEM & APRS

I've only installed a single ground rod with water assistance. After driving the first 3 ft with fence post hammer I decided to try water. It sure made it a bit easier using water, however. it did not flush soil away to allow dropping the rod into a "hole". It was still a battle driving the rod into it's final position. And if the rod were not in contact with the ground why was it firmly in place? There was no way one could pull that rod out of it's "hole".
I suspect actually flushing enough soil away to create a void is a function of the soil.
As far as "undisturbed soil" the NEC is referring to back fill conditions often found around foundations. Back filled soil is obviously disturbed. Probably requires counseling! if not properly compacted! Using water does not "disturb" the soil any more than driving a rod into it!

That said, driving a rod in sand is a good example of driving a rod into something that does not provide adequate contact to the rod. But this is where the UFER ground was developed! And keep in mind that actual grounding conditions are a function of soil resistivity (or conductance if you prefer). The best you can hope for is good contact with the soil. Then....the quality of the ground is a function of the soil.

 

Impact wrenches…. Water….

You “engineers” don’t know what you are doing.

Just make a contact with a BA op and have him pull from the other end. Easy peasy.

 

installer une mise a terre c'est bien ! savoir la mesurer c'est comprendre et faire le tour du sujet... A+ Chris

 

If the soil is loose/soft enough that putting water in it makes any difference, then likely the rod could be driven mechanically, anyway.

"Washing in " doesn't help if your soil is rocky. And actually makes it harder if you've got marine clay, since that material expands and pushes back when it's wet.

One of the NEC-accepted methods is to bury a rod horizontally in a trench at least 30 inches deep. I don't know how that would be possible if NEC also required "undisturbed earth". On the other hand, it is possible to compact the earth somewhat as you backfill a trench, whereas it may. not be possible to compact the earth around a washed-in hole.

Ultimately the requirement is to attain a low enough ground resistance. But very fews hams have the appropriate instrument or knowledge for measuring that. I would be interested in seeing any kind of actual study showing whether there is enough of a difference between a driven versus washed-in ground rod, to affect NEC compliance.

Seems to me that for a given earth condition, a driven rod would should be much better than, for example, an 8-foot hole drilled with a pressure-washer and the rod just dropped in. "washing-in" a ground rod will be somewhere between those extremes..

If I wasn't sure, I'd put in multiple ground rods all bonded together. So suppose the ground resistance of a washed-in rod is 100 times higher than that of a driven rod? Do you want to "wash-in" 100 ground rods, or pound just one, to achieve that 5 ohms?

For lightning protection, bonding is arguably more important than how your ground rods are installed. Whether or not someone can get their ground electrodes right, they should at least try get their bonding right.

 

A lot of nothing here, but people wanting to appear relevant.
This is a frigging hobby, and not some entertainment outlet. It would be nice to have knowledgeable Hams present stuff as simple as it is, and not repeat theory even we professional engineers do not use once out of school.
Again, a waste of time ... get a hammer folks !!!

 

I agree with everything, and the bigger the hammer or post driver the better.

However QRZ can be an "Entertainment outlet".... ..

 

Picked up one of these Bosch Hammer Drills for just over $300 USD brand new off eBay. I've used similar to drive 8 foot rods in a couple of minutes. Works great!

 

Hey...it's a ham forum....what did you expect?

 

Great practical idea ... beats my street road gang days as a gteen !!!