T & E outdoors

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We all know that T & E is not suitable for use outdoors without protection, but is there a specific regulation that prohibits it?
 
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I noticed that the 2012 version of BS6004 removed the "for internal wiring" that was in the title of the older editions.
 
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I have just gone onto the Batt website and yes the in doors clause seems to have been removed. All it says is it is for domestic use only. Well spotted. May be there has been a change in the mix for the PVC covering?

It would seem regulation 132.5.1 and 512.2.1 refer to equipment and accessories being suitable for the environment that they are being used in. However what seems to be the question is:- Has improvements with the cable made it so it now is suitable for out door use?
 
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If you think about it, The Earth isn't suitable for the environment.

It depends how long you think is acceptable.
 
The earth has been spinning around in the environment of space for quite a long time what do you mean when you say is is not suitable?

As to twin and earth there are two problems when used outside. One the cable shape makes it hard to seal, and two the plastic used is degraded by UV light, the latter being the main reason.
624B Twin & Earth LSZH Cable 300/500V BS7211 still states "Standard: BS7211 Electric cables. Thermosetting insulated, unarmoured cables for voltages up to & including 450/750V, for electric power, lighting & internal wiring, and having low emission of smoke and corrosive gases when affected by fire."

624Y Twin & Earth PVC Cable BS6004 A05VVH4-U still states "Standard: BS6004 Electric cables. PVC insulated, nonarmoured cables for voltages up to and including 450/750V, for electric power, lighting and internal wiring, BASEC approved"

Since it states "&" + "and" then one must take it that it can also be used for non internal wiring.
 
... the plastic used is degraded by UV light, the latter being the main reason.
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Since it states "&" + "and" then one must take it that it can also be used for non internal wiring.
So there is no degradation by UV light after all?
 
We have seen plastics evolve. OK we also get some times where the old plastic gets through as with the Woolworth problem in Australia. But the green gue which was found in some early versions of twin and earth seems to have gone.

However to identify LSZH from PVC is hard enough without trying to identify the version of PVC used. But the grey flat cable from when the grey was the lead coving to present day has clearly evolved. Polyvinyl Chloride has additives to adjust the flexibility in the main it is the leaching out of the additives which causes problems. We see it used with plumbing and windows outside with little problem even when not coloured black in fact although black may reduce the UV rays penetrating it can also raise the temperature and without special additives 60°C is the limit before it is damaged.

The point is it has been used since WW2 and looking at old installations and seeing how it has degraded does not really help in deciding if the new stuff will do the same. All we can do is be guided by the manufacturer. If it was all produced by one manufacturer that would be easy, but that is not the case.

So we have two problems:-
1) Can we use it today?
2) Is existing stuff safe?
As to first easy we look on the web site and it seems nothing says it is for internal use only. But for the second it is much harder, no one produces a book when doing a rewire giving all the details of cables and other items used. For the MCB we have a serial number, but for the cable nothing. Some times we don't need any info above what our eyes tell us, we can see it has been damaged. But if there is no damage detected then can't see how we can reject it simply because twin and earth has been used outside.

Even SWA can go down, in fact very little damage to the cable can cause water to increase the oxidisation process to an extent where the earth connection through the SWA is lost. So the simple answer is we test the cable and it can pass or fail like any other cable.

The question I would ask why is this cable for domestic use only?
 
What about PVC twin and earth in correctly installed egatube rigid plastic conduit, with all egatube joints correctly bonded into place, before any cable gets drawn in, by removing the screw-down draw point covers etc???
 
Kai, I'm sure that would be OK as long as the egatube provided sufficient mechanical protection for the installation.
 

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