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High Zs on ring final circuit

Discuss High Zs on ring final circuit in the Electrical Wiring, Theories and Regulations area at ElectriciansForums.net

first thing i'd do is investigate the high r2 value. that's end/end of the \RFC and nothing to do with the spur. then i'd do a hi-current Zs bypassing the RCD and MCB to eliminate any internal resistance errors.
 
Thanks Telectrix

If the r1+r2 was fine throught the circuit except the spur. But still getting a high r2 value end to end.

Surly that would mean there is a loose connection on the ring where the spur has been taken?



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Tel, could you explain the process of bypassing the RCD and MCB for the high current test. Would you just link the circuit line to the load side of the main switch temporarily? Anything to keep in mind for this - obviously I would say it's safest to do load free.
 
r2 is nothing to do with the spur. it could be a poor connection anywhere on the ring. and please differentiate betweem r and R. it's confusing if you mix them up.
 
Tel, could you explain the process of bypassing the RCD and MCB for the high current test. Would you just link the circuit line to the load side of the main switch temporarily? Anything to keep in mind for this - obviously I would say it's safest to do load free.

Bypassing the RCD/MCB


ISOLATE the circuit in question and double check that it is isolated!!


Link the CPC and Line at one of the socket outlets on the circuit in question


At the CU with your tester set to High ZS Loop place one probe on the outgoing side of the isolated circuit being tested and the other on the Line supply on the main switch.


Note reading on tester and REMOVE LINK BEFORE MAKING CIRCUIT LIVE AGAIN!!

Hope this makes sense!
 
Tel, could you explain the process of bypassing the RCD and MCB for the high current test. Would you just link the circuit line to the load side of the main switch temporarily? Anything to keep in mind for this - obviously I would say it's safest to do load free.
just been posted .. #29. by tony mc. and richard burns has posted an excellent diagram of the procedure .


High current Zs test with RCD.jpg
 
There was a socket behind a fitted set of draws that I wasn't showen. Had to remove draws and back pannel, was a bugger. I re-tightened connections and it sorted it.


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Nice one. Did that sort the high r2 value? What about the spur? Daz
 
The R2 for the ring dropped, also for the spur. I changed the faceplate for the spur and waggo'd the connections behind the draws.

To be honest, it was my own fault. I couldn't find the where the spur was taken from when I tested, I should have known there was another socket but the lady didn't know. Only the husband did when I returned.

Lesson learned.

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If you are measuring end to end for the cpcs that R2 reading is way too high, sounds like continuity is breaking down which may well not be at one of the sockets. How old is the circuit, if it goes back to the early seventies the cables may incorporate 1.0 cpcs. Maybe the R2 is correct and the R1 is incorrect. But from your continuity readings the Zs should be approximately 0.58 ohm for any accessory connected direct to the ring final, the Zs of any spurred outlet will depend on its proximity of connection to the ring final.
 
The R2 for the ring dropped, also for the spur. I changed the faceplate for the spur and waggo'd the connections behind the draws.

To be honest, it was my own fault. I couldn't find the where the spur was taken from when I tested, I should have known there was another socket but the lady didn't know. Only the husband did when I returned.

Lesson learned.

Sent from my SM-N910F using Tapatalk


Robo, please don't think I'm having a did, certainly not my intention, but " I waggod the connections" what exactly do you mean by that? as you said you had change the faceplate.
 
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Hi Murdoch,

That's correct and I will be tomorrow. , I noticed the high Zs prior to board change as I did pre tests and had the discussion with another Sparks who said he notes on his certs rcd protection. I said wasnt correct which brings me here.

I put the the circuit onto a 20amp tybe B until tomorrow as I've got to return with test cert.

Everything else was spot on apart from the other sparks who was there. No test cert, no Sleveing on cpc. No rcd on outdoor lighting, also the swa was just run along garden.

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not really an issue if it's self burying cable like many use around here :)
 
Robo, please don't think I'm having a did, certainly not my intention, but " I waggod the connections" what exactly do you mean by that? as you said you had change the faceplate.
Hi Pete,

I removed the double socket that was situated behind the draws and joined the cables and fitted a blanking plate.

I thought best, as the socket was not accessible.

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Hi Pete,

I removed the double socket that was situated behind the draws and joined the cables and fitted a blanking plate.

I thought best, as the socket was not accessible.

Sent from my SM-N910F using Tapatalk


Right many thanks was a bit confused but not now
 

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