No R1 on ring main?

[Cirrus]

I understand the H&S aspect but am not sure exaclt what regs it contravenes

 

[TonyM58]

Cirrus

i can quote the regs to you tomorrow when i got the book in front of me

main one is seperation of circuits, then theres the requirement for an RCD used as amain isolator to minimum 100mA S type

If, for example, you had smokes installed you can also be contravening seperate BS regs

get back to you tommorrow

 

[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

 

[Shakey]

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

Mutts, probably a typo, but surely you meant create two 20A radials?

And a 30mA on a shower, when was this a requirement? (unless of course you've gone 17th, in which case you can bin the 100mA for starters.......)

 

[Had8Lives]

How are you connecting the ends of the ring at the board when you test?

Regarding the 6mm earth, I'd Code/Cat 1 it and replace with 10mm.

 

[alan]

I understand it is a TT system. If the main earth cable is not buried it need only be 4mm
If buried should be 16mm.

Table 10c OSG.

 

[Cirrus]

10mm standard