No Earth Continuity on Ring Circuit

[NewbieRuffy]

HI all.. Some advice please if possible, i did see a post on here which related to this a few days ago when i first joined, i cant seem to find it now. ON testing earth continuity on a upstairs ring circuit i get zilch, nothing, zero!!! Both L's are good and come back with the same reading for both. I have checked all sockets in all rooms and apart from a couple of semi bad connections all looks good. As i am still pretty new to all this any advice please? :redface:

 

[drew35]

You could start by disconnecting one leg of the CPC at the CSU then use a long lead to do an R2 test at the nearest socket outlet, then move along until you find the break.

 

[NewbieRuffy]

Thanks Drew, did think of this, thought as yet havent purchased a 'wander lead' think its about time i did. Do you know if the 'megger' is any good?

 

[Silly Sausage]

Or...
Split the ring at the mid point then R1+R2 test each half.
This will show you which half of the ring the break is (if only 1!)
Then, on that leg, test at each socket until you get continuity, so the break will between that socket and the previous tested one.

Don't need to mess around with a wander lead either.

 

[tony mc]

And dont forget any FCU or supplies in the loft shower pump sockets etc!

 

[Richard Burns]

When you say you get zilch nothing zero do you mean you are getting a zero reading on your continuity tester or are you getting a very high value indicating open circuit.
If it is the former then there is likely an earth interconnection very close to the CU (assuming you are measuring your end to end continuity at the CU).
If you are getting an open circuit reading then as the posts above (easiest with Archy's suggestion).

 

[NewbieRuffy]

Thanks for the replies so far guys. Richard - I am getting a high reading as in my Kewtec tester starts at 999, i put it on continuous so that i can connect the probes to the two CPC's to measure e2e continuity (yes your right at the CU) and i get no reading at all, no beeb to indicate a reading and 999 stays on screen! As mentioned before L+N e2e test all OK.

 

[Octopus]

Get your MFT, set it to check the Zs, go round all the sockets, taking a reading at each and make a note of every reading. You will probably get a "big" difference between 2 readings - then look at each of these sockets in turn.

 

[rich.250]

As above posts, split the ring or r2 wander lead.

I have had a couple where it was the socket plate itself due to corrosion.....

 

[Risteard]

Thanks Drew, did think of this, thought as yet havent purchased a 'wander lead' think its about time i did. Do you know if the 'megger' is any good?

I have a 50 meter Megger wander lead and of course it is good for a long lead although it is very expensive!

 

[plugsandsparks]

I put up a thread a few days ago on a warehouse office ring that had been severed by a nail. I had open cct on cpc at DB. I connected one leg of the earth back in and ran around with a simple socket tester with LEDS and hopefully yours will be a break not between the first / last socket and the board, fortunately for me it was a break between sockets. I could not get the cable out so converted it to two radials.
This was after inspecting every socket, FSU and rose and following the cable in the suspended ceiling.

 

[telectrix]

make your own temp. wander lead. buy 100m of 1.5 single earth cable and use some ot that. resistance is about 0.5 ohms for 50meters.

 

[rich.250]

I put up a thread a few days ago on a warehouse office ring that had been severed by a nail. I had open cct on cpc at DB. I connected one leg of the earth back in and ran around with a simple socket tester with LEDS and hopefully yours will be a break not between the first / last socket and the board, fortunately for me it was a break between sockets. I could not get the cable out so converted it to two radials.
This was after inspecting every socket, FSU and rose and following the cable in the suspended ceiling.

So you found the fault live???