t&e cable for 2 way switch.

[JohnW2]

Wasn't there a big discussion a while back about HVAC eng's using g/y for a switchwire? I'm sure there was a consensus that it was, while not desirable, compliant (at that time anyhow).

As far as the regs are concerned, a conductor with any colour insulation can be used for any purpose, provided its purpose is properly 'identified' - whilst that identification should 'preferably' be throughout the length of the conductor, oversleeping just at the ends are acceptable. Hence, in a multicore (presumably flexible etc.) cable, it is reg-compliant (even if 'orrible practice!) to use a G/Y-insulated conductor, with appropriate oversleeving at the ends, as a live conductor.

The one specific exception is that a G/Y single cannot be used as a live conductor.

Kind Regards, John

 

[PBC_1966]

Hence, in a multicore (presumably flexible etc.) cable, it is reg-compliant (even if 'orrible practice!) to use a G/Y-insulated conductor, with appropriate oversleeving at the ends, as a live conductor.

It used to be endorsed by the wiring regs. (green rather than green/yellow then, but obviously the same principle):

 

[ban-all-sheds]

It used to be endorsed by the wiring regs.

But things change.

That's the way it works.

 

[PBC_1966]

What's changed in terms of whether it's allowed or not? The wiring regs. used to specifically acknowledge green being reidentified for other purposes so obviously allowed it. They may no longer give a specific example of such usage, but they do not disallow it either. So nothing has really changed in this respect between then and now, except for the green-to-green/yellow transition.

 

[ban-all-sheds]

And except for the fact that green no longer identifies a cpc.

But mainly I'm just trying to break you of the awful habit of looking to obsolete versions of standards to determine what is currently allowed or acceptable.

 

[PBC_1966]

And except for the fact that green no longer identifies a cpc.

Other than in the thousands of installations in which it's still present and serving that function.

But mainly I'm just trying to break you of the awful habit of looking to obsolete versions of standards to determine what is currently allowed or acceptable.

But it's already been acknowledged that the current version of BS7671 doesn't contain any prohibition on reidentifying the green/yellow conductor in a multiconductor cable to use for something other than earth. I was merely pointing out that in the past the regs. contained a specific reference to when such a need might arise.

And my question in response to Bernard's post about green/yellow vs. green for a single conductor was curiosity as to whether or not BS7671 currently says that plain green may not be used for anything other than earth now, given that green/yellow has been the prescribed combination for over 35 years and the regs. do sometimes have a tendency to "forget" about what's gone on in the past.

Certainly given that there must still be very many installations out there with plain green single conductors used as earths I do not think it would be a particularly good idea to use a green single for anything else. But does BS7671 actually prohibit it?

 

[ban-all-sheds]

But it's already been acknowledged that the current version of BS7671 doesn't contain any prohibition on reidentifying the green/yellow conductor in a multiconductor cable to use for something other than earth.

I'm not disputing that it contains no explicit prohibition.

I was merely pointing out that in the past the regs. contained a specific reference to when such a need might arise.

Irrelevant.

 

[EFLImpudence]

Certainly given that there must still be very many installations out there with plain green single conductors used as earths I do not think it would be a particularly good idea to use a green single for anything else. But does BS7671 actually prohibit it?

Yes. 514.4.5 The single colour green shall not be used.

I wonder why.

 

[PBC_1966]

514.4.5 The single colour green shall not be used.

Including if it's sleeved as something else at the terminations?

 

[EFLImpudence]

That is 514.4.5 in its entirety.

So, if it may not be used, I suppose there is no occasion where it may be sleeved.

 

[Risteard]

514.4.5 The single colour green shall not be used.

Including if it's sleeved as something else at the terminations?

If it is sleeved another colour then green hasn't been used. The sleeved colour has been used. But you wouldn't find a multicore cable to appropriate standards with a green core so it is academic really.

 

[stillp]

The fact that something is not prohibited does not mean that it is a good thing.

 

[PBC_1966]

If it is sleeved another colour then green hasn't been used. The sleeved colour has been used.

Which is what I was getting at. Not that I think that using a plain green single and sleeving the ends some other color (other than green/yellow for earth) would be a good idea, but does BS7671 actually prohibit it?

 

[EFLImpudence]

...but if "the single colour green shall not be used", why would anyone have any (for electrical installation)?

Consequently, how could it be sleeved?

 

[ban-all-sheds]

Which is what I was getting at. Not that I think that using a plain green single and sleeving the ends some other color (other than green/yellow for earth) would be a good idea, but does BS7671 actually prohibit it?

What part of "The single colour green shall not be used" is too hard for you to understand?

...but if "the single colour green shall not be used", why would anyone have any (for electrical installation)?

I'm sure that this cannot be the only source in the world:

http://www.gemcable.co.uk/products/index.php?cPath=7_79&filter[109]=Green&filter[108]=&filter[94]=&filter[112]=