High continuity resistance on ring final circuit

[kkkkk]

Hi peeps

I have continuity measurements on a ring final circuit of: L/L 1.4, N/N 0.78, E/E 1.7
Loose connections somewhere?
There is a new CU with RCD.
Insulation resistance measurements are good.
There is a boiler added into the circuit as a spur.
Any suggestions or comments?

THANKS!!

 

[Pete999]

2.5mm Twin and cpc or singles?

 

[Octopus]

Who's been fiddling?

 

[Rockingit]

Well, first glance says that you're using 6242Y, therefore the cpc is going to be roughly .7 again your main conductor, therefore your N & CPC values are [high-ish] but vaguely in keeping with this ratio, therefore you have an issue with your live conductor somewhere.

 

[kkkkk]

2.5mm T&E

Fiddling? Well, highly likely!!!

 

[Marvo]

Check connections/terminations for something corroded, loose or even overtightened. Maybe check where the spur is for a wire that got a haircut.

 

[kkkkk]

Cool - thanks guys!!!
Helpful as ever!!!!

 

[GLENNSPARK]

2.5mm Twin and cpc or singles?

and with values of:

L/L 1.4,

N/N 0.78,

E/E 1.7


what the hell has singles got to do with it?

the values of r1 and rn should be substantially the same...

not the case here....lol..

 

[Plonker 3]

A "ring" within a "ring" can cause them sort of readings on a circuit wired in single sometimes, also could be done with twin, but a lot more difficult to do with t&e

 

[GLENNSPARK]

A "ring" within a "ring" can cause them sort of readings on a circuit wired in single sometimes, also could be done with twin, but a lot more difficult to do with t&e

no it int..

i`v come across it plenty of times...

 

[Silly Sausage]

Maybe check the boiler spur for a wire that got a haircut.

It's the obvious place to start!

 

[amlu]

0.6 Ohm is not that bad, its hard to get it exactly right especially when many points on the ring, if you have bit of time get a wander lead and wander around doing continuity testing. e-e supposed to be higher anyway because of smaller wire csa.

 

[GLENNSPARK]

0.6 Ohm is not that bad, its hard to get it exactly right especially when many points on the ring, if you have bit of time get a wander lead and wander around doing continuity testing. e-e supposed to be higher anyway because of smaller wire csa.

yep...

lets all wander about for a bit...

 

[Plonker 3]

0.6 Ohm is not that bad, its hard to get it exactly right especially when many points on the ring, if you have bit of time get a wander lead and wander around doing continuity testing. e-e supposed to be higher anyway because of smaller wire csa.

But what about the L/L value being nearly the same value as the CPC

 

[Octopus]

0.6 Ohm is not that bad, its hard to get it exactly right especially when many points on the ring, if you have bit of time get a wander lead and wander around doing continuity testing. e-e supposed to be higher anyway because of smaller wire csa.

Sorry mate but I have to disagree. 0.60 ohms difference between 2 identical core sizes on a circuit is NOT good. Typical tolerance is + or - 0.05 ohms.

Looks like the issue should be investigated.

 

[telectrix]

it only needs 1 poor connection at a socket to give this sort of anomaly. nothing for it but to go round every accessory till you find it.

 

[Richard Burns]

Probably worth making sure you had good contact with your probes /clips first, if this was just one measurement, just catching a bit of insulation could cause this as well.

 

[GLENNSPARK]

it only needs 1 poor connection at a socket to give this sort of anomaly. nothing for it but to go round every accessory till you find it.

well ...its a ring final isn`t it...

so alls he has to do is get the wander lead out.....pick a leg at the board....

then go round with the breakout box....till he gets to the outlet where the value jumps up abnormally....

its either the outlet he`s testing....or the one prior to that one...

 

[telectrix]

problem with that,glenn, is that he's then reading through the socket and it's switch. better to go in at the back, as the actress said to the bishop.

 

[telectrix]

glenn can you get that CM400 at the right price, mate?