New ground rod test with a meggar
New ground rod test with a meggar
(OP)
How do you test a new ground rod with what I think is a standard Meggar(three wires, red, black, and green)? This is a new installation and I need 25 Ohm or less.
Thanks for the help
CB2
Thanks for the help
CB2





RE: New ground rod test with a meggar
RE: New ground rod test with a meggar
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RE: New ground rod test with a meggar
See discussion and links in
Thread238-34416
Thread238-11119
RE: New ground rod test with a meggar
1. Donald G. Fink "Standard Handbook for Electrical Engineers," 13th Edition, McGraw-Hill, Inc., 1993,
Section 38 Measuring Ground Rod Resistance on page 17-38
There are three major methods being applied:
1. Triangulation or three-point method
2. Ratio Method
3. Fall-of-Potential Method (ConEd in NYC uses)
2. IEEE Std 142-1991 IEEE Recommended Practice for Grounding of Industrial and Commercial Power Systems,
Section: 4.4.2 Methods for Measuring
Reference 1 Ditto
RE: New ground rod test with a meggar
A 'megger' is the generic name for an insulation resistance tester, which can deliver a high voltage at a very low current in order to measure insulation between conductors and between conductor and earth. The early ones were made by a company called Megger, and the name has stuck.
Ground impedance testing uses a different bit of kit called an earth resistance tester or some variation on those words. Off the top of my head, European manufacturers include:
Chavin Arnoux
Seaward
AVO-Megger
Have a look through Google, searching for the following keywords
Earth Resistance Instrument
Here's one page to get you started:
http://www.avointl.com/uk/products/ and look in the Building Wiring / Contractor column.
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RE: New ground rod test with a meggar
RE: New ground rod test with a meggar
The leads on the Ground Test Set (and there may even be four) represent the connections for the three(or four)-point ground rod tests. The meter ranges will read in ohms, maybe down to the hundreths or thousands, but certainly no higher than hundreds.
First, make sure that you have the right instrument. What is it that you have?
RE: New ground rod test with a meggar
Don't forget to disconnect the service earth (if fitted) and a can of water is usefull
RE: New ground rod test with a meggar
http://www.usace.army.mil/publications/armytm/tm5-683/c-14.pdf
for ground resistance test methods
RE: New ground rod test with a meggar
http://www.mytoolstore.com/ideal/ide05-01.html
RE: New ground rod test with a meggar
http://www.aemc.com/techinfo/
then click on Ground Resistance Tester