Thanks for the informtion. In general, a second ground rod is required to be driven only if the first is found to to have a resistance to ground greater than 25 ohms. Who usually provides the resistance test, the electrical contractor or inspector? I'm aware a lot of times the second ground rod is driven just to be done with it and not be concerned with a resistance test.
#12816 - 08/17/0201:48 PMRe: Gnd. rod resistance tester
Where I am in Maine 2 ground rods are driven as a matter of course. No one(at least to my knowledge) checks resistence to ground. Drive the 2 rods and be done with it. What about checking it with a copper sulfate electrode, commonly used to check cathodic protection on underground metal tanks and piping
#12817 - 08/17/0202:57 PMRe: Gnd. rod resistance tester
That is basically how it is done in my area. I was more curious than anything else. I thought there may of been a tester somewhere out there that was physically small and in the price range of $60.00 that was made specifically for measuring the resistance to ground of a ground rod.
#12818 - 08/17/0205:56 PMRe: Gnd. rod resistance tester
A copper sulfate electrode can't be that expensive? and then all you need is a 10meg ohm multimeter to check resistence. Whether or not this meets AHJ standards I have no clue. I can tell ya that soil conditions make a huge difference on how the copper sulfate elevtrode reacts.
#12819 - 08/17/0209:31 PMRe: Gnd. rod resistance tester