Live - Neutral reverse from plug in tester

Sparkingchip: 
526.9 states some definitive prohibitions.

For multiwire, fine wire, and very fine wire.

Last time I looked, 2.5 sqmm T&E had solid conductors.

For, e.g. singles, I suppose that one could use dual entry ferrules.

Someone I know removes the sheath of an unbroken T & E and bares conductors to go in grubscrew terminals then the spur gets wired as normal. He reckons he feels happier that if a screw unturns the ring is still connected. Of course the cpc remains unsleeved (or a bit of G/Y insulating tape applied.

I must admit I avoid junction boxes if at all possible and don`t like the split terminal type with grubscrews in anyway.

Sparkingchip: 
526.9 states some definitive prohibitions.

For multiwire, fine wire, and very fine wire.

Last time I looked, 2.5 sqmm T&E had solid conductors.

For, e.g. singles, I suppose that one could use dual entry ferrules.

Noooooooooooo!

I have dismantled a few consumer units and the like where people have done things like that, it doesn’t work.

ebee: 
 

Someone I know removes the sheath of an unbroken T & E and bares conductors to go in grubscrew terminals then the spur gets wired as normal. He reckons he feels happier that if a screw unturns the ring is still connected. Of course the cpc remains unsleeved (or a bit of G/Y insulating tape applied.

 

I must admit I avoid junction boxes if at all possible and don`t like the split terminal type with grubscrews in anyway.

I was actually shown how to do that in the college workshop by the instructor who was ex-MEB having done his apprenticeship in a Kidderminster carpet factory, having shown us he said he didn’t recommend it, but it was something we would see occasionally.

Sparkingchip: 
Noooooooooooo!

I have dismantled a few consumer units and the like where people have done things like that, it doesn’t work.

A CU seems to be an odd place to find singles.

Another problem with twisting conductors is that in the case of a cpc coming adrift from the terminal in the back of a socket outlet, an end-to-end reading taken at the disconnected ends of the ring at the cu would not reveal any problems, since the cpc ends would read continuous, and unless a 100%  inspection of all accessories was undertaken, the ‘unearthed’ accessory would never be found.

AJJewsbury: 
 

As a PS when the ring was first mooted in the 1940s some of the early advice suggested that the condutors of the ring shoult be unbroken. Now I presume this advice was not written by anyone with much practical nouse, as threading conduits or indeed just about anything, and s stripping cores part way along at each fitting is a non-starter

+1 for that - and the idea hasn't entirely gone away - certainly quite recently MK still produced a rectangular 30A JB specifically designed so that the main cable could be run through uncut. (Although that did beg the question of how to sleeve the c.p.c. to meet BS 7671 requirements)

   - Andy.

Green and yellow coloured P.V.C. tape.

Z.

whjohnson: 
 

Another problem with twisting conductors is that in the case of a cpc coming adrift from the terminal in the back of a socket outlet, an end-to-end reading taken at the disconnected ends of the ring at the cu would not reveal any problems, since the cpc ends would read continuous, and unless a 100%  inspection of all accessories was undertaken, the ‘unearthed’ accessory would never be found.

I always test all socket outlets in an installation, no exceptions. Well perhaps just one, where a hidden socket is located behind a heavy piece of furniture like a large free standing wardrobe.

Z.

100% check as required for initial verification is good. Trouble is Zoom, most post-installation PIRs or rather EIHCRs only ‘sample’ a few, or indeed none at all, with just the end to ends being recorded as being intact, and the r1+r2/4 results being ‘calculated’ one might say.

That unearthed accessory might stay in service for years without the missing earth connection ever being detected.

I wonder if we will ever see appliances which will be able to detect if an earth is present when plugged in, and will not function until there is? If a cnc machine can be made to refuse to start because of incorrect phase rotation at it's supply termianls, then why not a built-in cpc detector for all class 1 kit?

ebee: 
 

Someone I know removes the sheath of an unbroken T & E and bares conductors to go in grubscrew terminals then the spur gets wired as normal. He reckons he feels happier that if a screw unturns the ring is still connected. Of course the cpc remains unsleeved (or a bit of G/Y insulating tape applied.

 

I must admit I avoid junction boxes if at all possible and don`t like the split terminal type with grubscrews in anyway.

I have in my innocent youth used the uncut ring cable junction box method to add a spur. I used a Rock/Ashley J401 30 Amp three terminal circular junction box/joint box. This method can be useful if the main ring cable is a bit tight with little slack. It also means that there are only two 2.5s under the grub screws rather than three if adding a spur after cutting the main ring cable. It is essential not to cross thread the grub screws. To ensure that the little grub screws did not roll under the boards and get lost in mouse-land forever, I used to temporarily store them during assemble in the upturned junction box cover, which acted like a small storage saucer.

Z.