Ring interconnect.... Help please

[sythai]

Back to carry on with fault finding/ rectification tomorrow.

Came up with some dodgy results on consumer unit upgrade today.

RFC continuity

r1-r1 = 0.00
rn-rn = 0.00
r2-r2 = 0.13

Looks like I may have an interconnection somewhere along the line. New one for me.

Any tips from you more experienced chaps out there on best way to proceed without having to take every socket outlet off (x18.)

Was going to treat as long radial, draw a plan and use my r2 lead start at CU and work my way round with r1, then rn and see what springs up.

(Have downgraded mcb to 20amp until resolved.)

Thank you

Sy

 

[Tiny Spark]

Carry out a full RFC test taking R1-R2, R1-N, and R2-RN readings at each socket.
Should identify the offending part of the circuit.

 

[Octopus]

Time to get your wander lead out and take some sockets off. Its a bit hit and miss but you'll get there.

 

[Sintra]

Could be a hidden jb close to cu which I have come across before. Open one socket and check r1. rn and r2 and if readings look good then this is more than likely the problem.

 

[Richard Burns]

0.00 sounds like it is less than one metre from the db and 0.13 about 4m away (you did null before testing didn't you?)
Theoretically the resistance rise on checking the continuity from one leg end to each socket should be less where there is an interconnection then where there is not, but this is probably too subtle for the real world.

 

[Des 56]

The standard figure of 8 test may be the best way forward
The test just as well just be referred to as the interlink test because its possibly its best function

 

[sythai]

(you did null before testing didn't you?)

Yes made sure of that quite a few times, did think at first it was my leads playing up.

I'll keep you posted this could be fun - directly above the CU is a fully tiled bathroom floor, so hoping an offending JB isnt buried under there.

Looking at it again the figure of 8, does look like a better option - thank you.

Think this is just one of those jobs with a few surprises:

- tncs with a ze of 0.44, rang DNO not interested unless over 0.80!
- customer was getting shocks (changing pendant) even with main switch on CU off : original Wylex BS5419 up the spout, in off position getting 230v N - E to ! (long gone in the bin now, nice shiney Hager thats better)

Have a good day

Sy

 

[Tiny Spark]

Yes made sure of that quite a few times, did think at first it was my leads playing up.

I'll keep you posted this could be fun - directly above the CU is a fully tiled bathroom floor, so hoping an offending JB isnt buried under there.

Looking at it again the figure of 8, does look like a better option - thank you.

Think this is just one of those jobs with a few surprises:

- tncs with a ze of 0.44, rang DNO not interested unless over 0.80!
- customer was getting shocks (changing pendant) even with main switch on CU off : original Wylex BS5419 up the spout, in off position getting 230v N - E to ! (long gone in the bin now, nice shiney Hager thats better)

Have a good day

Sy

Good luck