On 07/12/2017 09:44, harry wrote:
On Wednesday, 6 December 2017 20:31:35 UTC, wrote:
Hi All

I have broken into a ring main to extend it to another room. Essentially cutting the return from one socket and then connecting each side of the extended ring to one of the cut ends.

I test the extended ring and it was sound (ie only continuity between the corresponding pairs of wire). I have just connected it to the main ring and did a quick continuity check. Live is ok but it seems that neutral (blue) and earth now have continuity. Given I tested the extended ring it would appear that the original ring suffered this problem. However if this was the case wouldn't the RCd at the MCU have tripped before.

Any ideas?

Thanks

Lee

Neutral and earth are bonded together back at the substation.

That is true.

It's important that this is the only place they are bonded.

That is certainly not true for TN-C-S (PME) supplies which are the
default "standard" for installs these days.

(the clue is in the "M"!)


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/