driving ground rods in glacial till- how??

[Katey]

We are re-doing our electrical system and the power company is insisting on two new ground rods, 5/8" copper-clad, driven 7 feet into the ground. Our dirt is glacial till, meaning 70% rocks, varying roughly from walnut-sized to fist-sized. When driving t-posts we sometimes have to try a couple of places before we find a spot where it will go in as far as it needs to.

How should we go about this? We could start driving from a ladder, with either a sledge or a post driver. We could rent an auger to get us down the first three feet or so, and hope that conditions improve below that. A friend suggested that we could look into hydraulic drilling, but those rigs don't seem available for rent.

Any recommendations or suggestions?

Thanks in advance!

[Scrounger]

A friend of mine who used to live in the mountains made a "bit" for drilling into the rock out of the longest masonary bit he could find and steel rod. Worked pretty good....

You can also ask the eclectric company how they would do it (or an electrician...). Maybe even pay them to do it.

[wrongwayrick]

A trick I learned from an electrician is to use a hammer drill that has a hammer only option. It wont drive it through a rock but it will slide it into hard ground very quickly.

[agmantoo]

Use the hammer drill. Get a big one that will chuck onto the ground rod. Hold the rod vertically and turn the hammer drill on. After the ground rod is partially driven you can let go of the rod and just observe the hammer drill driving the rod. It may take some time but it will get the job done. Another method is to grind the pointed end of the ground rod to where you can start a 1/2 inch hex nut on the end. Then take a grinder and remove enough of the outer portion of the nut to where the nut OD is just slightly larger than the rod. The rod will drive much easier since there will be reduced friction on the outer wall of the ground rod. The short coming of this is that the rod does not make as good contact with the soil initially but the soil will settle and firm to the ground rod with time. Sometimes you just do what you have to do!

[Katey]

Thanks all! Will report back when the deed is done (probably about a week from now, if anyone else wants to chime in before then).

Cheers,

Katey

[Oldcountryboy]

Originally Posted by Scrounger

You can also ask the eclectric company how they would do it (or an electrician...). Maybe even pay them to do it.

Former electrician here. You can also burry the ground rods lenghtwise if you can't get them drivin. The ditch has to be at least 2 1/2 feet deep. When in a open ditch I sometime drive them down as far as I can and then I bend the rest of the rod over to lay in the ditch.

But if you have no ditch to put the rods in then you just have to do the best you can. I usually start with a t-post driver to get it started and then I switch over to a heavy sledge hammer. I have used a big hammer drill before but sometimes even they don't work.

[Katey]

After a couple of weeks of dreading it, we rented an auger (to get us down about halfway; probably wasn't necessary) and a power hammer. We only had to drill one extra hole with the auger, and watching the hammer driver push that stake smoothly into the ground was enlightening!

I've always had a rule of thumb: "If you have to rent something that says HILTI on it, you're in over your head" but no more! Bring it on!

Thanks, everyone!

Katey (and Al)

[hunter63]

Originally Posted by Katey

I've always had a rule of thumb: "If you have to rent something that says HILTI on it, you're in over your head" but no more! Bring it on!

Thanks, everyone!

Katey (and Al)

Congrats.
LOL, wiser words were never spoken, another word to watch for is "Ditch-Witch" (note on front of machine,"Contact with bladewhile running, will result in death")

[Ken Scharabok]

I have put in several through gravel by starting with a T-post pounder and then finishing with a sledge hammer.

[SCRich]

I tried a T-Post driver and that just did not cut it here with a lot of slate. I did get a Harbor Freight demolition hammer and got it driven. I did 10ft rods every 10 feet around the premiter of the home before backfilling and connected them with 00 tinned copper. All of this was cad welded to the main service rod and I got 2 drop leads coming off of the ring. One goes to my office/amateur radio room and the other goes to a steel box mounted on the foundation wall with conduit to the road. All services (Telephone and hopefully sometime cable) goes to this box and must be grounded by the provider via a surge arrestor before it goes into the house.

If you are doing a lot of this a cheap harbor freight electric jackhammer will do the trick!