However if that single ground rod is not 'good enough' by a fairly arbitrary and difficult to properly test metric, then a second ground rod is required.
In many locations, it is common practice to simply install 2 ground rods as more economical than putting the effort into the testing to show that a single ground rod is acceptable.
I think you are just not seeing the opinions as being about the same.The writing (#8) is from EC&M and is confusing as are all the questions on those new tests, so, less than 25, I don't need the second one and more than 25, I need the second one. So, why are different professional opinions?
"Performance" in this context is relative. In practice, adding a second electrode will do very little no matter what the ground resistance is, or how far away it is arbitrarily placed. Just another example of Code panel whims that have no basis in fact or common sense.Six feet to the second electrode is only the NEC minimum and you likely do not get much more performance out of the second electrode if it is any closer then 6 feet but you generally would bet better performance with more distance between them.
I understand, but I think the NEC looks at six feet as the closest because you get the sphere of influence of each far enough apart that you will get more performance out of two rods spaced at six feet then at one or two feet apart. You may get more conductivity out of 12 feet then 6 feet but not as significant of a change as you likely get when going from 1 foot to 6 feet apart."Performance" in this context is relative. In practice, adding a second electrode will do very little no matter what the ground resistance is, or how far away it is arbitrarily placed. Just another example of Code panel whims that have no basis in fact or common sense.
"Performance" in this context is relative. In practice, adding a second electrode will do very little no matter what the ground resistance is, or how far away it is arbitrarily placed. Just another example of Code panel whims that have no basis in fact or common sense.
In many locations, it is common practice to simply install 2 ground rods as more economical than putting the effort into the testing to show that a single ground rod is acceptable.
-Jon
Sorry, this picture is better and I added a bonus for my mistake
Of course it's true. Let's say you're actually able to get 25 ohms with two rods - still not even close to tripping a breaker. One rod at, say, 40 ohms is going to give you the same relative performance - that is, still not enough to trip a breaker.Not true.
Only a single ground rod is required.
However if that single ground rod is not 'good enough' by a fairly arbitrary and difficult to properly test metric, then a second ground rod is required.
In many locations, it is common practice to simply install 2 ground rods as more economical than putting the effort into the testing to show that a single ground rod is acceptable.
-Jon
IMHO testing after the installation is the inspectors job.
:lol::lol::lol:
That is some funny stuff.