Ground Rod

Originally Posted By: Greg Fretwell
This post was automatically imported from our archived forum.



When I bought my house I had a bad ground. It looked OK to the HI but the first time I touched the stove in bare feet it knocked the snot out of me.


I replaced the Weaver clamp with the rusted out screws with an acorn and things were OK.


Since then I have upgraded everything.


Originally Posted By: Mike Parks
This post was automatically imported from our archived forum.



If Jeff’s first picture is an electrode, nothing connected to it is allowed.


Mike P.


Originally Posted By: roconnor
This post was automatically imported from our archived forum.



Greg Fretwell wrote:
I had a bad ground ... the first time I touched the stove in bare feet it knocked the snot out of me.

Sounds like the green bond/ground wire wasn't run back to the service panel where it should have been bonded to the neutral.

That is really the only way to clear dangerous touch voltage from a fault (where a hot wire contacts the metal case). Just connecting the metal case or the green bond/ground wire to a typical earth rod doesn't generate enough current to trip a breaker (i.e. "clear the fault").

Lets say ya have a 120V appliance with the metal case only connected to an earth rod meeting the 25 ohm resistance requirement in the model codes. The fault current from a hot wire touching the case would be I=V/R or 120/25 = 4.8A ... not enough to ever trip a breaker ... ![icon_eek.gif](upload://yuxgmvDDEGIQPAyP9sRnK0D0CCY.gif)

As I noted before, the reversible clamps used outside would get flagged every time ... also acorn clamps used on BX/AC cable for the reasons Jerry noted (ya shouldn't have BX/AC cable exposed outside anyway).

But I believe Jeff is talking about an indoor earth rod here. If the clamps are just spinning on the rod, then it's probably just a typical pipe clamp not made for rod attachment when reversed.


--
Robert O'Connor, PE
Eagle Engineering ?
Eagle Eye Inspections ?
NACHI Education Committee

I am absolutely amazed sometimes by how much thought goes into doing things wrong