Weird continuity results on ring

Capn Ahab · Sep 10, 2012

Strange test results on an old ring:

L-L 0.14 ohms
N-N 0.15 ohms
E-E 1.12 ohms

L-N (this is where it gets weird):
1st d/skt 0.07 ohms
2nd d/skt 0.08 ohms
3rd d/skt 0.21 ohms
4th d/skt 0.36 ohms
5th s/skt 48 ohms!
6th d/skt 48 ohms!
7th d/skt 48 ohms!
Spur d/skt 48 ohms!

WTF!? This was the end of the day, so I didn't have much time to investigate. After checking the connections I found one L and one N not connected in the 6th d/skt, so reconnected them thinking that might solve the prob, but got the same readings. But even so, I don't get how one half of the ring can be affected, while the other half isn't.

Is it the outlets? Anyone got an idea??

Getting back to this first thing tomorrow...

Cheers

Deleted member 26818 · Sep 10, 2012

It's not a ring.
Could be a dodgey radial, or perhaps a dodgey spider.
Perhaps even two radials?

Darkwood · Sep 10, 2012

You've stated its a ring... just because you get an end to end reading dosn't prove anything, try the ELI reading at the fuseboard and then at each point to see if you have a small ring with extensive radials attached it should give you prgressive slightly higher readings up to the mid point any unusual readings may show multiple sockets on a radial a practice ofen seen in the olden days.
Also be aware some terminal screws are coated with to stop the metal oxidising and this can also mess reading up.

Capn Ahab · Sep 10, 2012

How can it be radials when I get the end to end results? Didn't have time for ELI, so will do that and check each outlet thoroughly first up.

Deleted member 26818 · Sep 10, 2012

How can it be a ring with those readings?
Only one of them is anywhere near what would be expected if it were a ring.

Richard Burns · Sep 11, 2012

Make sure it is a ring first.
If it is a ring then your end to end on e is way out and needs addressing.
For the L-N readings if you are taking readings through a socket adapter I would suggest dirty contacts / loose termination on 3 and 4 and then at 4 or 5 one of the live conductors is twisted to the outgoing but loose in the terminal. Disconnect and remake the connections and check again or check at the back of the sockets.

gdr7671 · Sep 14, 2012

Your meter may be faulty. By your readings at the cu l-l and n-n =21.5 metres length of ring. Your e-e reading = 103 metres. Did you short L to n In out legs of rings at board then l-n at each socket? If so you should have a reading of 0.075 ohms at each socket. Do the same with L&E cables and you will find the fault when you get an odd reading at a socket outlet. There is a definite problem with the cpc connections.

Brightspark2 · Sep 14, 2012

Did you find the problem?...

Capn Ahab · Oct 21, 2012

Brightspark2 said:
Did you find the problem?...

Yep, the sockets in the kitchen were part of the upstairs ring. Nice little lesson in not taking stuff for granted...

kamikizzy · Oct 22, 2012

Glad you got it sorted

but are these figures correct ?
5th s/skt 48 ohms!
6th d/skt 48 ohms!
7th d/skt 48 ohms!
Spur d/skt 48 ohms!

Thats a massive reading at the sockets or should it read .48?

gdr7671 · Oct 22, 2012

kamikizzy said:
Glad you got it sorted but are these figures correct ?
5th s/skt 48 ohms!
6th d/skt 48 ohms!
7th d/skt 48 ohms!
Spur d/skt 48 ohms!

Thats a massive reading at the sockets or should it read .48?

I should get your meter re calibrated. Do as prescribed in guidance note 3 check r1 plus r2; or take r2 readings. Make sure you are happy before signing off any certificates. I would be worried to have such high readings without an obvious reason for this. Good Luck