R2 Testing Help

[markthespark]

Hello i havent done much testing before so i am trying to brush up on my Testing skills before i join Elecsa, i have a couple of questions about R2 testing please.

I understand how to carry out R1 R2 tests using method 1 and that we do them to calculate the Zs of our circuit Zs=Ze+R1+R2

But i dont understand if we are carrying out an R2 test using a wander lead what sort of maximum values will we be looking for and also how can we calculate the Zs without the R1 reading.

Also out of interest on EICR why is it necessary to do the R1 R2 tests when we can measure the Ze and Zs and calculate the R1 R2 values?

Many thanks in advance.

 

[telectrix]

R2 tests with a wander lead will give you the cpc resistance on it's own at each point.a R!+R2 can then be done at the furthest point. to get a Zs value when measuring just R2, you will have to measure it, not calculate. on a EICR, it's permissible to omit R1+R2 readings ( also depends on the limitations of the report ) as long as the Zs readings are within limits.

 

[markthespark]

Thanks for clearing that up Telectrix, where would i find maximum R2 values?

Cheers.

 

[trebor]

Also out of interest on EICR why is it necessary to do the R1 R2 tests when we can measure the Ze and Zs and calculate the R1 R2 values?

Zs minus Ze is not an accurate way of calculating R1 + R2 because Zs will include any parallel earth paths, R2 proves in theory cpc continuity but again parallels are a bummer, as telectrix says ZS is the important thing on EICR and R +R2 can be ommitted or lim