continuity of a ring

[NWDS]

Afternoon/evening all, I have just installed a new ring in a kitchen,6 d/skts, before the plasterer has been in I have checked continuity of ph/ph 0.25 ohms N/N 0.36 ohm why would I get such a difference in my readings ?? , I have ckecked all the connections ( fronts off and connectors used ) and still I get the 0.10 ohms difference, I would have thought that the readings should be about the same ??????????????.

Regards NWDS

 

[green-hornet]

One problem you get is live and nuetral are of different lengths, another is the termination could effect the continuity (integrity). Do the rest of the tests and test each socket outlet to see if you can track down a loose connection.

Try testing r1+r2 then same using the nuetral see if there is any difference.

 

[SPECIAL LOCATION]

Afternoon/evening all, I have just installed a new ring in a kitchen,6 d/skts, before the plasterer has been in I have checked continuity of ph/ph 0.25 ohms N/N 0.36 ohm why would I get such a difference in my readings ?? , I have ckecked all the connections ( fronts off and connectors used ) and still I get the 0.10 ohms difference, I would have thought that the readings should be about the same ??????????????.Regards NWDS

Oh yes! they should be, maybe 0.01 diff at most IMHO! :|

0.36 - 0.25 = 0.11

0.11 of 2.5mm copper conductor would imply that the Neutral is about 14.8meters longer!!!

i.e.

(0.36 / 7.41)x1000 = 48.5m

(0.25 / 7.41)x1000 = 33.7m

thats a bit tooo much of a discrepancy or my thinking!

As GH says you need to go back an check again...

I would diss the ring off treat it as a radial..

join LN&E together at one end & go to all sockets reading L-E and N-E

they should remain substantially that same as each other just incrementing up appropriate to the length of the cable..

using the figures in table 9A page 166 O-S-G you can verify correct lengths.

I think you will find either a bad connection OR a damaged section of cable!

 

[Robojin]

I think you will find either a bad connection OR a damaged section of cable!

Along the lines of: partially clipped the N insulation on one socket?

 

[WarrenG]

Has any plaster boards been fitted ready for the plasterer?

Could be a nick in a neutral somewhere??