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#12810 - 08/16/02 02:20 PM Gnd. rod resistance tester
Frank Cinker Offline
Member
Registered: 07/29/01
Posts: 317
Loc: Pennsylvania
Is there a simple, somewhat inexpensive tester to measure ground rod resistance? I've checked my Grainger catalog and couldn't find anything.
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#12811 - 08/16/02 03:10 PM Re: Gnd. rod resistance tester
watthead Offline
Member
Registered: 10/13/01
Posts: 182
Loc: South Carolina
Yes there is a simple clamp on but not inexpensive over $2000. AEMC and EXTECH offer them.
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#12812 - 08/16/02 03:15 PM Re: Gnd. rod resistance tester
Bill Addiss Offline
Member
Registered: 10/07/00
Posts: 4196
Loc: NY, USA
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.


There is another type they have that is under $200



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

Bill

[This message has been edited by Bill Addiss (edited 08-16-2002).]
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#12813 - 08/16/02 04:14 PM Re: Gnd. rod resistance tester
sparky Offline
Member
Registered: 10/18/00
Posts: 5545

This one goes for $113.......
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#12814 - 08/16/02 04:50 PM Re: Gnd. rod resistance tester
Bill Addiss Offline
Member
Registered: 10/07/00
Posts: 4196
Loc: NY, USA
Sparky,

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

this one is more suitable for Ground Resistance testing.

Bill
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#12815 - 08/17/02 03:23 AM Re: Gnd. rod resistance tester
Frank Cinker Offline
Member
Registered: 07/29/01
Posts: 317
Loc: Pennsylvania
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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#12816 - 08/17/02 10:48 AM Re: Gnd. rod resistance tester
walrus Offline
Member
Registered: 07/25/02
Posts: 671
Loc: Bangor Me. USA
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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#12817 - 08/17/02 11:57 AM Re: Gnd. rod resistance tester
Frank Cinker Offline
Member
Registered: 07/29/01
Posts: 317
Loc: Pennsylvania
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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#12818 - 08/17/02 02:56 PM Re: Gnd. rod resistance tester
walrus Offline
Member
Registered: 07/25/02
Posts: 671
Loc: Bangor Me. USA
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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#12819 - 08/17/02 06:31 PM Re: Gnd. rod resistance tester
sparky Offline
Member
Registered: 10/18/00
Posts: 5545
oops, yeah it's a megger.....
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