Joan, The ground ring around the Pentagon requires ground rods 1" X 20' every 15 feet, most contractors use an air compressor and jack hammer for the task. BTW, did I tell you guys one of the reasons I've been scarce around here is the move from Dulles to the Pentagon ? Surprise !!!!!!!
Re: 20 ft Ground Rod#5286 11/13/0106:56 PM11/13/0106:56 PM
Joan, I just had to install some 10" rods in an area with rock at 3'. I had a soil testing company drill 4" holes 11' deep and installed the rods with sand mix concrete as back fill. The drilling cost about $400 per rod. Don(resqcapt19)
Re: 20 ft Ground Rod#5288 11/13/0111:52 PM11/13/0111:52 PM
Sparky, It takes a bit, but the old building was poorly grounded when built (1941-43) and patched here and there since. This is the first major remodel and lotsa things that were taken for granted years ago will not be overlooked this time. Course, uh.... we also have to fill the hole.
Re: 20 ft Ground Rod#5289 11/13/0111:57 PM11/13/0111:57 PM
You can use sectional ground rods to get just about any length. You will need something heavy to drive them-air comressor and jack hammer- depending on the local earth at the job site. Most supply houses will be able to order them for you Good luck
Re: 20 ft Ground Rod#5291 11/14/0109:03 AM11/14/0109:03 AM