But I do not think a ground rod bored into rock would make an effective ground, there would be air space around it (and is rock a conductor?) as electricmanscott said dig a hole and toss it in horizontally.
Bob Badger Construction & Maintenance Electrician Massachusetts
I have used the ground rod driver attachments on a few drills all with good results.
It is not a garuntee of getting the rod in though..
My best advice is a hilti te72 or comparable size drill. As far as spline "VS" SDS-Max I ahve seen no real difference. Maybe the spline is tougher. It looks it. But I have never broken or seen a broken SDS-Max chuck unless somebody tried to hammer without a bit.
I think the SDS-Max is plenty tough and man what a labor saver.
On a strange side note I drive nail-in concrete anchors with a dull 5/8" drill bit. And wish they made a tip specificaly for this. It is so much faster and easier when you have a dozen of the anchors to put in in one place and you have the drill anyway to drill the holes.
Maybe they do make on and I just have not found one yet.
Check out http://www.groundhawgs.com/ someone has apparently beat ya to it... well, kinda... Can't go through rock or frozen ground with the groundhawg...
A similar idea using rotary hammer is intriguing.
Neat idea.
[This message has been edited by sparky66wv (edited 05-13-2003).]
-Virgil Residential/Commercial Inspector 5 Star Inspections Member IAEI