Ring Circuit testing

[mrmatt]

Hi

I have installed a ring with 7 sockets on it

when insulation resistance testing these are the results i get

L-N >500Mohms
L-E >500Mohms
N-E 6.8Mohms

as this is a new circuit i am not willing to accept the N-E reading of 6.8Mohms as i consider it well low although it does pass the regs.


Thing is if i split the ring at the first socket and test both ends of the cable at the CU i get >500Mohms and if i test at both ends of the disconnected socket same reading >500M ohms. I thought this may mean a faulty socket so i put the cables into a connector block at the socket and i get the same low reading when i test at the board.

Has anyone got any suggestions?

Thanks

Matt

 

[poirot]

Have you disconnected the ring completely at the c/u prior to testing?

 

[mrmatt]

Have you disconnected the ring completely at the c/u prior to testing?

its a new circuit so it hasnt been connected to CU yet still on dead tests

 

[telectrix]

dodgy socket?

 

[olly w]

Have you proved the continuity of the ring yet?

If not you might be breaking the ring in a second place and disconnecting the fault.

 

[mrmatt]

Have you proved the continuity of the ring yet?

If not you might be breaking the ring in a second place and disconnecting the fault.

continuity has been checked and results were as follows

L-L loop 0.35 ohms
N-N loop 0.35 ohms
E-E loop 0.6 ohms

ill recheck these results tomorrow though

 

[Sav]

I would say one of the cables is damaged between N-E.

Sav

 

[dixon9]

One of the back boxes with moist plaster over the neutral/earth connection terminals? If the IR has improved tomorrow (plaster dried out) it could well be that...?

 

[cornburn]

Keep your tester going and take off and wiggle each socket, when the reading changes you know where to look for a problem, that's still a fairly high reading so it's probably not going to be anything obvious to the eye.

 

[mrmatt]

sorted thanks guys. broke the ring back down into smaller sections and found one of the capping nails had penetrated the cabe. luckily i was doing a quick test before getting a spread on the go

 

[telectrix]

well done!

 

[Sav]

Told you...Damaged cable !!!!

Have a great and safe day everyone,
Sav