Ring Final Test - Neutral >19.99kOhms

[vwes59]

Just checking, what I think I already believe.

Doing a pre-install test of some outdoor sockets on a ring final. So far, confirmed bonding, incoming polarity, Ze and Pfc and RCD Test on circuit, everything fine and within regs.

However on testing Ring Final, Line came out fine (0.7), Neutral came out >19.99kOhms, CPC came out as expected (1.67 x Line). Line and CPC were within an expected range, and a live Zs test confirmed those readings (0.32).

So here's the thing. Everything except the Neutral Rn test passed. I did these tests at a socket, not at the board so the Line, Neutral and CPC were still connected, only the ring final circuit was de-energised.

It's likely I have a break in the neutral somewhere, but given I have the ring final connected to the rest of the house in the board, is it possible the neutral reading has been skewed because I'm essentially testing the entire neutral of the house ? Before I go splitting the ring etc, should I disconnect the ring final neutrals at the board, jump and re-test ?

Hope that makes sense.

 

[Strima]

You should disconnect at the board when doing RFC dead testing, this will remove parallel paths etc.

 

[telectrix]

with circuit isolated, take the 2 N's out of the N bar in CU then try rN on them. if still over range, you have a break. then if you connect 1 of the N's to it's corresponding cpc, test for Rn+R2 at each socket. soon find the break.

 

[vwes59]

Thanks. That's what I thought. So much for a simple Outdoor socket install, and I've got another ring final extension to do tomorrow...joy! Ring Final faults must cost us so much time and money.

 

[telectrix]

Thanks. That's what I thought. So much for a simple Outdoor socket install, and I've got another ring final extension to do tomorrow...joy! Ring Final faults must cost us so much time and money.

i consider finding faults to make me money.

 

[vwes59]

Well, the client has decided not to pursue the fault, so I've backed away from doing the install. I've put it in writing that there is a fault that needs to be dealt with, so if anything happens subsequently I can't be bitten by it.