DIY Doctor UK DIY Forums

i have just tested r1, r2, and rn, the results as follows:-

r1 = 0.46
r2 = 1.24
rn = 0.47

r1 and rn results are similar which they should, but r2 is much higher than it should, i belive should only be 1.67 times that of the phase conductors due to the reduced size of the cpc.....any suggestions why im getting such a high reading....the property is approx 40 years old. i hace niceic inspection shortly and would like to have all the answers or be able to fix the problem..

cheers scott

Is the CPC, connected to any parallel paths, is metal conduit also forming part of earth path have you disconnected that and pig tails to back boxes.
KB

[quote="kbrownie"]Is the CPC, connected to any parallel paths, is metal conduit also forming part of earth path have you disconnected that and pig tails to back boxes.
KB[/quote]

thanks for the reply, no other parrellel paths to the best of my knowledge, no earth condiut is used, but the cpc'c are connected to metal back boxes.

Try checking all CPC are tight in terminals this could also effect reading and you have good contact with your probes/croc-clips on the in and out CPCs
KB

Hi,
as the installation is 40yrs old the chances are the cpc is in fact 1.0mm not 1.5mm as now, this was normal in the 1960's, try a recalc based on that.
Any parallel earths would reduce your reading rather than increase it so don't think thats an issue,

regards & good luck,
SPARX