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#12810 08/16/02 05:20 PM
Joined: Jul 2001
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Is there a simple, somewhat inexpensive tester to measure ground rod resistance? I've checked my Grainger catalog and couldn't find anything.

Joined: Oct 2001
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Yes there is a simple clamp on but not inexpensive over $2000. AEMC and EXTECH offer them.

Joined: Oct 2000
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Frank,

I think you are going to have to define inexpensive.

Watthead,

The EXTECH Clamp-on is under $1400 - we sell them here in the store.
[Linked Image]

There is another type they have that is under $200

[Linked Image]

Look here:
https://www.electrical-contractor.net/the_store/EX/GRT_Main.htm

Bill

[This message has been edited by Bill Addiss (edited 08-16-2002).]


Bill
Joined: Oct 2000
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[Linked Image]
This one goes for $113.......

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Sparky,

The one that you pictured is meant to measure high resistances.

this one is more suitable for Ground Resistance testing.

Bill


Bill
Joined: Jul 2001
Posts: 311
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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.

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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

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walrus-

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.

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Frank

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.

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oops, yeah it's a megger.....

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