Mutts

Hey cirrus

sorry to get involved this late but i have only just started to use this forum, Anyway heres my understanding of what going on.

r1 = the end to end reading on the phase conductor on the ring
r2 = the end to end reading on the on the cpc (earth) conductor on the ring
rn = the end to end reading on the nuetral conductor on the ring

these readings should be taken at the consumer unit using a low ohms continuity tester.

so if you are not getting an end to end reading on the phase conductor you are not getting an r1 reading. which would suggest that somewhere on the ring circuit the phase coductors have seperated. (eg fallen out of the back of a socket outlet or been damaged in some way) ive also had cases where the grubb screw on the socket outlet has been screwed against the insulation and is not making contact with the copper conductor inside so look carefully. if your really unlucky the problem could be in a junction box somewhere.

The reason why you are still getting a zs reading is because the ring circuit is fed from both "legs" of the ring

hopefully you'll find it but if you don't you need to seperate the ring main and create 2 x 16 amp radial circuits.

As for the RCD protection on a TT system. You need to have a 100ma RCD time delay mainswitch But you need to make sure you also have 30ma RCD protection on the usaul circuits ie Socket outlets, showers etc. Are there RCBO's available for the consumer unit you are dealing with?

Its always worth doing all your essentail tests before working on existing circuits as well as after at least you know what your up against from the beginnig

Good luck dude.........Mutts