3 x RFC all with no continuity

[JosephandAmber]

Working on an empty property which has 4 RFCs. 3 of these are showing no continuity across R1 R2 and Rn. The wiring is around 30 years old and each room has 2/3 single sockets. Each of these sockets is fed by a single 2.5mm T&E. What's going on here? Is it likely the sockets are being fed from a ring under the floor with a junction and spur for each socket? This could give plausibility for their being a break in one of the junctions but it just doesn't make sense. I'm heading back tomorrow to investigate properly but keen to know if anyone has come across similar before?

 

[Mike Johnson]

What are you at the property to do?
Do you get continuity from each of the Sockets back to the CU?

 

[radiohead]

You say 4 RFC's and 3 have no continuity on r1, rn, and r2........and there is a single 2.5 T/E at each socket. Well in that case the three are clearly not RFC's!
Assuming other tests are satisfactory if you are there to alter these circuits treat them as 20a radials, or if they need a 32a OCPD they will have to be rewired as rings.

 

[7029 dave]

What size fuse are these circuits on.

 

[Dustydazzler]

If you have 2 cables at the fuse board but only 1 at the sockets then at some point someone has split the ring under the floor most likely in a JB

not a particulary big issue and most likely been like this for years

 

[littlespark]

Can you tell with the age of the sockets themselves? Ie 30 year old, splash painted the same colour as the wall will be original on rfc... anything new, or doesn’t match might be additions.
Also listen out for squeaky floorboards.... hint that they have been lifted.... that could be where the joints are.

 

[hasel5]

My ring Has all the ground floor sockets spurred of the upstairs to save cable back in the day just a thought

 

[FatAlan]

Presumably the end to end testing was done at the DB if you only have single cables feeding at the sockets? Looks like you'll have to test for continuity for each socket back to the one leg to try and make sense of the arrangement or start pulling floorboards up. Sounds like you may be right about an RFC with the sockets dropped off in spurs which I've come across a few times but you should still get an end to end reading at the DB.

 

[buzzlightyear]

What's the betting a radial.

 

[FatAlan]

Could some of the RFC legs have been mixed up between OCPD's i.e out leg on one and return to another so in effect you haven't identified both ends?

 

[JosephandAmber]

What size fuse are these circuits on.

Currently 32A. Marked as ‘rings’ on the existing cables, each with two cables terminating in the CU hence I’m treating them as such without yet having managed to find continuity.

 

[JosephandAmber]

Can you tell with the age of the sockets themselves? Ie 30 year old, splash painted the same colour as the wall will be original on rfc... anything new, or doesn’t match might be additions.
Also listen out for squeaky floorboards.... hint that they have been lifted.... that could be where the joints are.

Sockets appear to be same age as the wiring. 30 years. Hence I’m slightly confused. No evidence of DIY.

 

[JosephandAmber]

Could some of the RFC legs have been mixed up between OCPD's i.e out leg on one and return to another so in effect you haven't identified both ends?

I thought this. I checked continuity between the legs of the three supposed RFCs and still nothing.

 

[Mike Johnson]

Do the sockets actually have power to them?
Have you checked continuity from the sockets back to the CU.

 

[Mike Johnson]

Just realised, 30 years old, it's a Ring Main not a Final Ring Circuit, Ring Mains flow from right too left instead of from Left too Right, to bring them in line with the rotation of the Earth they where changed to Final Ring Circuits, unless anyone knows of some other reason. ??

 

[Wilko]

Currently 32A. Marked as ‘rings’ on the existing cables, each with two cables terminating in the CU hence I’m treating them as such without yet having managed to find continuity.

Hi - well if there is no end to end continuity of L, N and CPC at the board, then I suspect they were never installed as a ring. It’s ”normal” for one conductor to lose continuity with a poor connection but I’ve not seen all 3 and in all 3 circuits, just saying. Is there a test sheet that shows (historic) continuity?

 

[7029 dave]

So no crossed legs no end to end continuity, only 1 pair present at socket outlets, leads me to jb radials.

 

[Mike Johnson]

Well I think we all have reached the same conclusion, the ring has been broken mid run into two radials off the same MCB this could be confirmed with a check from socket's to CU. C'mon Joseph put us out of our misery.

Then why only one set of conductors in each socket, T&E taken out to re-use elsewhere. ?

 

[Deleted account]

post 2 needs answering.

 

[Gavin John Hyde]

I see cables labelled ring all the time. Cooker ring. Light ring. Immersion ring. Was never a ring final circuit but back a few years thats what people called circuits.
A guy in his late 50s asked me round to change a light recently and said the lighting ring does the whole house. Of course it was a radial circuit!

 

[westward10]

Strangely enough I was tracing a line to earth fault around some office wall lights, one circuit with mcb banging straight out. We have a 2.5 T&E radial to the grid switch, from here two 1.5s which I assumed split either side around the office but I had the fault on both sides so something made me do a continuity check and sure enough the two cables were a ring.