# Currently reading:Very high Zs on ring main.

Discuss Very high Zs on ring main. in the UK Electrical Forum area at ElectriciansForums.net

#### Lesley19

What would be the fault with a very high Zs at all sockets on a ring main, the sockets are an average of 68.10 .

The lights are.67 and the is a socket radial circuit which is at .51 .

Welcome to the forum.

Welcome. You need to build up the picture a bit at a time, starting with the Ze.
Remember Zs = Ze + (R1+R2)
....so if Ze is ok then the answer lies with the circuit itself somehow.
(The two other circuits you mention suggest the Ze is within limits.)

You say it's a ring final circuit. Did you do dead end to end tests and figure of 8 tests before the live Zs test?

And your r1 and r2 values ?

How do these compare to rn?

What would be the fault with a very high Zs at all sockets on a ring main, the sockets are an average of 68.10 .

The lights are .67 and the is a socket radial circuit which is at .51 .
If other circuits are giving under an ohm then it looks like a typical TN system, then having a very high Zs for your RFC really suggests the CPCs are badly connected.

Quite an achievement really, given they ought to form a ring so two connections in parallel...but as @Julie has asked, have you checked the end-end values r1, r2, and rN to see if it looks sane from that point of view?

Another thing is to use a wander lead and see what your resistance from any socket's CPC (e.g. using socket test adaptor) is to the MET, that ought to be consistent with the r2 value and if not its another part of the puzzle that could point the way to an answer..

Might help if you responded to what has been asked.

@Lesley19 you are allowed to ask questions, however silly they may seem, if the replies aren’t making sense to you. We all had to start somewhere!
Or did you have an EICR done and this was one of the findings?

Last edited:
@Lesley19 you are allowed to ask questions, however silly they may seem, if the replies aren’t making sense to you. We all had to start somewhere!
Or did you have an EICR done and this was one of the findings?

@Lesley19 you are allowed to ask questions, however silly they may seem, if the replies aren’t making sense to you. We all had to start somewhere!
Or did you have an EICR done and this was one of the findings?
Hi, it turned out to be a very corroded socket outlet, and not a ring. It was two radials. An EICR had been carried out.

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