Minor works R1+R2 measurement

[gazdkw82]

I think I may have asked this question a while ago but not sure on what the answer was and it's come up again at our monthly tool box talk.

When doing a Minor works for an additional spurred socket or extra light fitting on a circuit, should the R1+R2 measurement be taken from the protective device or the socket/fitting you have spurred from?

 

[sheppertonspark]

r1 + r2 is also measured for initial verification. Ze + (r1 +r2) is approximately equal to the expected Zs. Ensures that the circuit is safe to energise before "live" Zs reading is taken. Apparantly is acceptable to calculate r1 + r2 from Zs-Ze when carrying out future testing (advice from NICEIC) sounds a bit wrong to me !

 

[Pete999]

r1 + r2 is also measured for initial verification. Ze + (r1 +r2) is approximately equal to the expected Zs. Ensures that the circuit is safe to energise before "live" Zs reading is taken. Apparantly is acceptable to calculate r1 + r2 from Zs-Ze when carrying out future testing (advice from NICEIC) sounds a bit wrong to me !

R1+R2 you mean? r1,r2 and rn are an end to end resistances of a RFC conductors, yes I'm a pedant, before you comment.

 

[Ian1981]

r1 + r2 is also measured for initial verification. Ze + (r1 +r2) is approximately equal to the expected Zs. Ensures that the circuit is safe to energise before "live" Zs reading is taken. Apparantly is acceptable to calculate r1 + r2 from Zs-Ze when carrying out future testing (advice from NICEIC) sounds a bit wrong to me !

Calculating R1+R2 is only acceptable at the design stage using known values of resistance and the applicable correction factors for instances like change in temperature etc etc.
It’s must certainly wrong to subtract the Ze from Zs to come up with a value to be written down on a certificate/report.

 

[sheppertonspark]

r1 + r2 is als

R1+R2 you mean? r1,r2 and rn are an end to end resistances of a RFC conductors, yes I'm a pedant, before you comment.

I stand corrected (well sit down corrected to be precise)

o measured for initial verification. Ze + (r1 +r2) is approximately equal to the expected Zs. Ensures that the circuit is safe to energise before "live" Zs reading is taken. Apparantly is acceptable to calculate r1 + r2 from Zs-Ze when carrying out future testing (advice from NICEIC) sounds a bit wrong to me !

Calculating R1+R2 is only acceptable at the design stage using known values of resistance and the applicable correction factors for instances like change in temperature etc etc.
It’s must certainly wrong to subtract the Ze from Zs to come up with a value to be written down on a certificate/report.

I agree, pointless to "back" calculate R1 + R2

 

[Pete999]

r1 + r2 is als

I stand corrected (well sit down corrected to be precise)

o measured for initial verification. Ze + (r1 +r2) is approximately equal to the expected Zs. Ensures that the circuit is safe to energise before "live" Zs reading is taken. Apparantly is acceptable to calculate r1 + r2 from Zs-Ze when carrying out future testing (advice from NICEIC) sounds a bit wrong to me !

I agree, pointless to "back" calculate R1 + R2

als?