How do I test an earth stake - please help!

[Geordie Spark]

Usual method is to use a Loop Tester which is connected to the phase and neutral at the consumer unit and the green/yellow cable connected to the stake. The reading is in ohms and should be below 200, the lower the better.

Alternatively you can use an earth electrode tester which is a long winded way of doing it, most sparks will use the loop tester.

Has anyone used a Metrel/Alphatek1557 mft for this?

If so, what setting do you use?

 

[Engineer54]

When you're measuring Ra values of around 100 Ohms as you are for most RCD protected TT systems then accuracy isn't quite so critical so the EFLI method is perfectly adequate.

If however, you're measuring Ra or Rb values for say a generator or transformer then accuracy is far more important so an earth electrode resistance tester is the instrument of choice (This is a common 2391-10 question).

And..... Don't forget Lightning Protection systems, need to use an earth electrode resistance tester here too!!!

 

[Engineer54]

Has anyone used a Metrel/Alphatek1557 mft for this?

If so, what setting do you use?

Like other MF Testers when used for earth rod testing using aux test electrodes, .... It's fine for domestic and light to medium commercial installations!!!