Testing - R2 result

[redman]

hi all,

Ive been doing quite a bit of testing lately, at college & work.

Its all starting to sink in, but the one thing im unsure about is the R2 result.

On one of the ring circuits the results were:

r1 = 0.08

rN = 0.08

r2 = 0.12

R1 + R2 = 0.05

R2 = ?

Would the R2 result be the same as r2 divided by 2 ?

So that would make it 0.06 ?

If not, what is best way to check the R2 result ?

Any help appreciated,

Cheers

 

[sparkytim]

Not to sure what you after but you only have to record R1+R2 OR R2 on the test sheet.

For a Ring circuit R2 is not really required as you can obtain the R1 + R2 result when conducting the full Ring Main test.

R2 only normally recorded on PIRs as alternative to prove continuity of CPC

 

[a1]

As Sparky Tim ^^^

I assume though, that you want to know why the r2 is higher than the r1 & rn Readings?

If so, I assume that your readings are for a length of Twin & Earth Cable (T&E)? In that case, the r2 will be approximately (X)1.67 more than the r1 & rn readings.

If they are wired in "Singles" then the r1, r2 & rn readings should be near enough the same.

 

[a1]

On one of the ring circuits the results were:

r1 = 0.08

rN = 0.08

r2 = 0.12

R1 + R2 = 0.05

R2 = ?

Would the R2 result be the same as r2 divided by 2 ?

So that would make it 0.06 ?

If not, what is best way to check the R2 result ?

Any help appreciated,

Cheers

No Mate,

It is Divided by 4:

r1 = 0.08 = 0.08/4 = 0.02 ohms

rn = 0.08 = 0.08/4 = 0.02 ohms

r2 = 0.12 = 0.12/4 = 0.03 ohms

Therefore R1 & R2 = 0.02 ohms + 0.03 ohms = 0.05 ohms

As said by ST, above - It is only one or the other (R1+R2) OR (R2) that you record.

Also, lower case letters are used on the end to end resistance test (r1, r2 & rn). (The reason that I mention this, is not to be picky, but when if and when you go for your C&G 2391, they have to to be word perfect, or you will lose marks).

HTH.

 

[redman]

That makes more sense now.

On the test sheet it does say to use either R1 + R2 or R2,

now I know why !

I didnt actually test the R2, was just wondering what to expect if I did or how to work it out.

Cheers lads

 

[Andy™]

requirement is to test the earth (R2)

now in college on a test board, R2 is very easy with wonder lead - however, in the real world, its not. so live (R1) is used as the 'wonder lead'. so R1R2 is commonly done