Help needed with Ring(s) problem

[LlandrilloSpark]

Fellas could do with your valued opinion on the following

Bungalow, 40 year old wiring, TNCS, two 30a ring finals for socket outlets but i fear lots of diy additions, IR reading of 0.01 Meg Ohm Line-Earth on both legs of both rings, also i think the rings are connected as only 25Ohm resistance between line conductors from each ring.

The install has worked perfectly and not blown the 3036's i 40 years.

Any thoughts?


Cheers

 

[topquark]

Almost sounds as if a nail or the like has gone through both rings effectively joining them.

 

[sparkinlee]

Ummm... first thought is that you need to find the 25 Ohm connecting between the two rings first because that will be meaning that the 0.1 MOhm IR result appears in both places. (It's probably only an IR fault on one of the rings, but appears on both because they are linked together.)

Then the usual things... everything unplugged? split the rings and test each half, etc...

 

[Marnik]

10K line to earth,me thinks something still connected somehow, Perhaps aerial amp in loft? as for res. of 250 ohms between rings, maybe borrowed neutrals?

 

[sparkinlee]

maybe borrowed neutrals?

I would have thought this unlikely on 30a ring final circuits...

 

[telectrix]

it could be that an alteration has been connected with one leg to each ring final, and the 25 ohms is a poor connection somewhere.

 

[Marnik]

Correction misread should be 25Ohms not 250 Ohms!!!

 

[Marnik]

nothing unlikely in this game!!!!

 

[sparkinlee]

only 25Ohm resistance between line conductors from each ring.

What were the resistance values between the neutrals in each ring, and between the CPCs in each ring?

 

[topquark]

What were the resistance values between the neutrals in each ring, and between the CPCs in each ring?

:icon4: That'll be a good indication if it's been wired like that.

 

[LlandrilloSpark]

Cheers lads
TV ARIEL BOOSTER!, somebody mentioned it, well this is strange, I unplugged appliances one at a time just to eliminate any faulty ones, the last one was a very old tv ariel booster, when i unplugged it the fault went, i plugged it back in the fault was there, i checked again 3 times and i thought i'd solved the problem on at least on circuit, but after being energised the fault returned!

Im a bit stuck but customer is willing to chuck 4-5 hours at it tomorrow and i really want to solve it.

r.e Neutral and Earth IR's both over 25 Meg

 

[ChristianG]

Good luck, hopefully not a hidden connection like jb under floor or old connector blocks tiled over. Ah the joys!

 

[vernam616]

Why did you not unplug everything before you carried out IR test???

Schoolboy error

Edit: if it were me testing id be stripped each point down and testing between, draw it out too, its a long arsed process but will pinpoint your fault

 

[ezzzekiel]

What were end to end readings,?

 

[LlandrilloSpark]

continuity of the ring final conductors, 0.46 r1 & rn, 0.58 r2, pretty much similar for both circuits, all what i expected really?