GRN Testing: Clamp-on vs 3 Point
- Thread starter rbaltes
- Start date
- Status
bphgravity
Senior Member
- Location
- Florida
Re: GRN Testing: Clamp-on vs 3 Point
I would go with the most convienent and cheaper method (probably clamp-on). Even if they are not completely accurate, which I have heard reports of, so what. The best you would need in most cases is a ball-park idea of ground resistance. Knowing actual ground resistance has very little value.
I would go with the most convienent and cheaper method (probably clamp-on). Even if they are not completely accurate, which I have heard reports of, so what. The best you would need in most cases is a ball-park idea of ground resistance. Knowing actual ground resistance has very little value.
ron
Senior Member
- Location
- New York, 40.7514,-73.9925
Re: GRN Testing: Clamp-on vs 3 Point
Is this a residence or a commercial building. How involved is the grounding electrode system. Most clamp-ons can't handle multiple grounding electrodes, as you get contamination from the influence of and adjacent electrode. There are new selective GEC testers that may help in a complicated system.
http://www.leminstruments.com/online-store/scstore/an-ground-08.html
Is this a residence or a commercial building. How involved is the grounding electrode system. Most clamp-ons can't handle multiple grounding electrodes, as you get contamination from the influence of and adjacent electrode. There are new selective GEC testers that may help in a complicated system.
http://www.leminstruments.com/online-store/scstore/an-ground-08.html
Re: GRN Testing: Clamp-on vs 3 Point
The 3point FOP is as accurate as the clamp on method, however, the clamp on will not give you accurate values on mutable or large ground systems as stated in the manufactures manual. The clamp on will give you false good values (low values 5 to 7 ohms) if not used properly.
The 3 point FOP is a valid IEEE method and the clamp on is not, so, you need to understand why the test is performed and the type of system you are measuring.
The 3point FOP is as accurate as the clamp on method, however, the clamp on will not give you accurate values on mutable or large ground systems as stated in the manufactures manual. The clamp on will give you false good values (low values 5 to 7 ohms) if not used properly.
The 3 point FOP is a valid IEEE method and the clamp on is not, so, you need to understand why the test is performed and the type of system you are measuring.
- Status