Discuss Insulation resistance problem in the Periodic Inspection Reporting & Certification area at ElectriciansForums.net

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Yes its a new install.

Well assuming you are the one who installed it you would know if there are any hidden outlets with something still connected, in which case sounds like its time to split the circuit down half by half until you find the culprit. Keep us posted with your findings. Could well be a pinched live in metal back box
 
I assume there are no USB integrated sockets or surge protectors in circuit? If there are then it might be worth testing at 250V to see if the fault appears to clear.

If you are getting 0.00 MΩ it is often worth changing to low ohms and see if the result is a short or if the value can give an indication of the type of connection.
If you also get 0.0Ω on continuity you know it is a direct contact.

Because you are getting this reading on both side of the ring it sounds like either a cable manufacturing fault or a repeated installation error where someone else was unaware of the the cable location and has damaged it in all directions. however this seems unlikely and may just indicate a wiring error on some accessories.
 
It also may assist,to describe how you separated the RFC,how and where it was tested. It seems unfortunate that the same identical fault should appear on both halves.

If the fault is described accurately,it should take only one more splitting of the RFC,and the re-testing of the now disconnected six cable ends,to determine whether it is a fault,or a testing error.

Accurate terminology and result nomenclature,is vital. It is not "picky",to pull anyone up,on mistakes of this nature.

If you took your pregnant missus on holiday, to a foreign land,and asked regarding medical assistance,you would not be thrilled to find out it was 100 miles or 100 minutes or 100 pounds away...

With an accurate description of a circuit layout,together with test methods,and results,a fair guess can be attempted,at possible issues,and additional methods to apply.
 
Probably a daft suggestion, but sometimes the daft ones are the best ones - you've removed your temporary links at the board (sometimes installed line -> cpc to measure R1+R2 of other circuits) if you used them?
 
Probably a daft suggestion, but sometimes the daft ones are the best ones - you've removed your temporary links at the board (sometimes installed line -> cpc to measure R1+R2 of other circuits) if you used them?

The OP has stated its a ring final circuit, test links betwenn R1 & cpc would only be used on radial circuits.
 
The OP has stated its a ring final circuit, test links betwenn R1 & cpc would only be used on radial circuits.

Hence why I said "to measure R1+R2 of other circuits" - the scenario I had in mind:

OP puts temp link in to measure all his R1+R2's (new install, could be lots of circuits). Then does his rfc tests (end to end and R1+R2) and then terminates the cables back in the mcb etc. Then he comes along to test IR as a whole board (which is acceptable) forgetting he has a temp link, which would give him a dead short line->cpc.

I know it's a long shot, and very unlikely, but it's a valid suggestion in my mind still and it has cost me nothing to put it forward.
 
Did you have any look finding the fault? Did you try completely splitting the ring to every individual point and testing every single cable run? Have a good look at every point on the circuit, I had a similar fault once, turned out when one of the sockets was being pinned back into the backbox the socket pin caught on one of the live conductors and caused a nick! And it wasn't me before anyone says anything!!
 
Yes found the problem yesterday morning, it was a plaster board screw straight through the wire which the plasterer have carefully placed. Problem solved, thank you to all who gave useful advice.
 
Although the fault has been found, I am still a bit confused about the fact the OP split the ring and got the 0.00 reading on both legs, yet the OP only mentions one plaster board screw through one cable!!?? I can only assume that the OP connected the ring circuit back at the cu, then split it at the mid point, thus creating a radial??

Please correct me if I have read the other posts correctly, I have a bad hang over this morning, so I'm not totally compus mentus (not even sure this is the correct spelling)!!

Cheers

Jay
 
Despite you being non compos mentis, a good thought.:17::lightbulb:
I had not thought of that particular scenario to account for the readings discrepancy.
 
Although the fault has been found, I am still a bit confused about the fact the OP split the ring and got the 0.00 reading on both legs, yet the OP only mentions one plaster board screw through one cable!!?? I can only assume that the OP connected the ring circuit back at the cu, then split it at the mid point, thus creating a radial??

Please correct me if I have read the other posts correctly, I have a bad hang over this morning, so I'm not totally compus mentus (not even sure this is the correct spelling)!!

Cheers

Jay

That's what confused me also. If the ring had been split into 2 separate legs then surely one leg would be clear of fault, or have I missed something also?

I have only come across multiple short circuit faults on a new install twice before.

Once it turned out the apprentice at the time had pinched a few cables when fixing back the front plates.

Second was a faulty batch of cable, this turned out to be a right pain to sort in the end, extremely annoying!

At the time I couldn't believe it could be the cable and spent a good while trying every other option. Eventually I pulled out a leg between 2 sockets and stripped back the sheath to find the insulation very thin and missing in some places on the live conductor. Nightmare! :frown2:
 
Although the fault has been found, I am still a bit confused about the fact the OP split the ring and got the 0.00 reading on both legs, yet the OP only mentions one plaster board screw through one cable!!?? I can only assume that the OP connected the ring circuit back at the cu, then split it at the mid point, thus creating a radial??
He could only have done what you've suggested, split the RFC at a socket and left the legs connected at the CU or Vicky-Vercky! If the RFC was disconnected at the CU the fault would of been isolated from the rest of the installation's other circuits?
 
Don't mind me while I bump some old threads. Just doing the rounds. Ignore the thread if it's not current topic, it'll soon drop off the list, but if the thread interests you, feel free to reply. :)
 
Don't mind me while I bump some old threads. Just doing the rounds. Ignore the thread if it's not current topic, it'll soon drop off the list, but if the thread interests you, feel free to reply. :)
You monkey, like a dozy git I read through the entire thread not realizing I'd already posted in it and then only checked the date on the very last post!
 
You monkey, like a dozy git I read through the entire thread not realizing I'd already posted in it and then only checked the date on the very last post!
It's okay. Part of the intention is to dig up some gems. As I don't know much about sparky stuff, I can only check stats for the threads and see what used to have a bit of traffic and doesn't now. Assuming it's just got lost a bit over time.
 

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