Driving ground rods

ground rods can be installed in a varity of ways. However, the differences in the installation can and usually do effect the usefulness of the rod. I personally do not ever install one. I install them in pairs spaced a minimum of the distance that they are long. It is possible to drive one or even two rods in poor grounding conditions and not get the

The code says up to 45 degrees is OK. If you have a question, drive another rod at least 6 feet away and connect them together

Thanks for the replys.

Ed

On Fri, 31 Mar 2006 17:59:36 -0700, "SQLit" Gave us:

Always water your ground rod daily in desert settings. :-]

Dwight gives : vertical rod Resistance =(rho/2*pi*L)(ln(4L/a)-1) where rho is the soil resistivity L is the rod length and a is its radius

horizontal rod: Resistance =(rho/4*pi*L){ln(4L/a)+ln(4L/s) -2 +s/2L -smaller terms) where the length is 2L depth s/2 and the rest as above

for L=3m a=0.01m and s =0.3m R vert/R horiz =1.07/1.24 =86% This is assuming uniform earth which you don't have. Use a longer horizontal rod (say by a factor of at least 2 and 3 would be better); or a grid such as a 3 point horizontal star with arms of length L (this gives, for the same L, less than 60% of the resistance of a single vertical rod.) Hey, a star or grid uses more conductor but it is still cheaper than trying to get a good ground with a vertical rod. --

Don Kelly @shawcross.ca remove the X to answer

...snip...

Don,

Thanks for the detailed reply ... now have a 'PhD' in horiz driven grnd rods.

Ed