We used 5/8" copper clad steel, or sometimes 3/4" copper clad
steel
rods. We also used rotary impact hammers to drive the rods down....
often right through a rock or whatever.

Hammer-only mode? Or "rotate & hammer" mode?

---Joel


Hope I did not confuse ! I used a rotary impact hammer in all my years
of ground rod driving, but only used impact mode..... the rotary mode
would only turn the hammer head, not the rod . .. anyway. Most of the
time I had a sized Bosch tool, not some cheap import.

--- Ed K7AAT