Checking for correct ground reading
- Thread starter bryan
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You don't do it with an ohm meter. This is one way it is done.bryan said:
http://www.kilowattclassroom.com/Archive/GndTestArticle.pdf#search="measure ground resistance"
jwelectric
Senior Member
- Location
- North Carolina
bob said:
Would checking the amperage from a circuit tied to the electrode and doing Ohm's law work?
allenwayne
Senior Member
bryan said:
Your asking if a Yugo can ride like a Rolls. NOPE !!!!!! Although a fluke meter can do many things reading resistance to ground in a potential test senario is not one of them.
- Location
- New Jersey
- Occupation
- Journeyman Electrician (retired)
jwelectric said:
It seems like it would but I don't think that this is an accepted standard method of testing. Years ago an old timer told me to disconnect the conductor that comes from the ground rod and put it on a 20 amp breaker. Now flip the CB on and read the current with an Amprobe. Do a little math and there you have it your ground rod resistance reading. No good huh?
allenwayne
Senior Member
infinity said:
Maybe I`m getting old and stupid.But if you took the grounding conductor off the ground rod and put it inline with an energized circuit with a cb inline there would be no load and the cb would trip out as designed to do.I know you didn`t say hook it up to an energized circuit but I fail to find the reason that a non energized breaker as opposed to an energized breaker would make a difference.
bphgravity
Senior Member
- Location
- Florida
Allen, Trevor is talking about connecting the GEC to the grounding electrode to a breaker. The circuit breaker will not trip as the return path through the ground rod, earth, and back to the source would be effectively high enough to reduce the current below the trip rating of the circuit breaker. Even at 25-ohms earth return resistance, the flow of current would only be 4.8 amperes.
The reading would only be an idication of the total return path and not just the earth resistance to the ground rod. And it would only indicate the current flow at that point in time under the particular conditions during the test.
The reading would only be an idication of the total return path and not just the earth resistance to the ground rod. And it would only indicate the current flow at that point in time under the particular conditions during the test.
Bryan said:
The earth resistance to the ground rod. Even with the best of equipment you are checking at that point in time uner the particular conditions during the test.
I don't see a point in doing tests of the ground rods, unless there are some major problems.
The earth resistance to the ground rod. Even with the best of equipment you are checking at that point in time uner the particular conditions during the test.
I don't see a point in doing tests of the ground rods, unless there are some major problems.
- Location
- Massachusetts
dlhoule said:
The only point is the inspector can require a test if you only drive one rod.
I just drive two and move on.
bphgravity
Senior Member
- Location
- Florida
I completely agree there is no point in checking ground resistance. Weather and soil conditions change on nearly a daily basis thus changing the original results of the test. An installation here in Florida may not be able to obtain 25-ohms with one ground rod during the dry winter months, yet the same installation may read well below 25-ohms in the summer rain season...
- Location
- New Jersey
- Occupation
- Journeyman Electrician (retired)
allenwayne said:
I did say to turn the breaker on:
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