Underfloor Heating

[JohnW2]

That would depend how long your entire professional life extends back, as already mentioned table 4D5A covered flat T&E in 16th editions.

[I presume you mean 4D2A] ... and, as already mentioned, I see nothing about 4D2A which says that it doesn't still cover flat T+E (as well as does 4D5) - so I don't think it can be said to be 'wrong' to use 4D2A for it, even today. It may be 'in one's interest' (higher CCC) to use 4D5, but the differences between the two tables are few (and small), and they cover different installation methods (A & C being the only overlap).

Kind Regards, John

 

[ban-all-sheds]

4A3

 

[securespark]

Care to elaborate?

 

[securespark]

That would depend how long your entire professional life extends back

Mid eighties.

as already mentioned table 4D5A covered flat T&E in 16th editions.

Yes. I mentioned it!

So it is very likely that you have been.

Along with many other sparks too, I shouldn't wonder.

 

[JohnW2]

4A3

Thanks; I hadn't noticed that before. However, I'm not sure that it really alters the situation much. Provided the 'thermoplastic' insulation is PVC (which it usually is), I would have said that (just as with the Table titles themselves) T+E satisfies the description for 4D2 just as much as it satisfies the description for 4D5, wouldn't you?

Kind Regards, John

 

[JohnW2]

Care to elaborate?

4A3 gives the relevant Standards and relevant CCC Table numbers for different types of cables. However, as I've just written to BAS, I think that T+E still satisfies the entries in that table which send you to both 4D2 and 4D5 - so not really any different from the table titles themselves.

Kind Regards, John

 

[JohnW2]

So it is very likely that you have been.

Along with many other sparks too, I shouldn't wonder.

If you've ever installed a 2.5mm² ring final using Intallation Method 100, you have actually effectively been using 4D5, even if you didn't realise it - since such a circuit would be non-compliant with 433.1.103 if you used Table 4D2A!

Kind Regards, John

 

[ban-all-sheds]

Thanks; I hadn't noticed that before. However, I'm not sure that it really alters the situation much. Provided the 'thermoplastic' insulation is PVC (which it usually is), I would have said that (just as with the Table titles themselves) T+E satisfies the description for 4D2 just as much as it satisfies the description for 4D5, wouldn't you?

No.

 

[securespark]

Care to elaborate?

 

[JohnW2]

Provided the 'thermoplastic' insulation is PVC (which it usually is), I would have said that (just as with the Table titles themselves) T+E satisfies the description for 4D2 just as much as it satisfies the description for 4D5, wouldn't you?

No.

I see! In what way do you feel that PVC insulated and sheathed T+E does not qualify as "PVC insulated, non-armoured cables for voltages up to 450/750V, for electrical power, lighting and internal wiring"? (particularly given that the referenced 4D2 itself also refers to 'multicore', 'copper conductors', 'thermoplastic insulated and thermoplastic sleeved' and 'with or without a protective conductor).

Kind Regards, John

 

[ban-all-sheds]

Because the same row in the table explicitly mentions flat cable and identifies 4D5.

You'd have to be either stupid or perverse to think that you were not to use that specific table for that specific cable type.

 

[JohnW2]

Because the same row in the table explicitly mentions flat cable and identifies 4D5. You'd have to be either stupid or perverse to think that you were not to use that specific table for that specific cable type.

I wouldn't call it either stupid or perverse. Rather, I'd describe it as taking the word of the regulations as they are written, not as I think they should have been written - a principle which I thiught you championed.

There is no doubt in my mind that PVC T+E satisfies both of the descriptions given in that row of the table, both the one which identifies Tables 4D1/4D2 and the one which identifies 4D5. If they had wished the former of those descriptions to have excluded T+E, they could very easily have said so, but didn't.

Whatever, in practical terms it's pretty irrelevant, apart from being an example of rather imperfect writing of the regs. Anyone who is aware of 4D5 is going to use it, rather than 4D2A.

I would suggest that the individual Tables in Appendix 4 should be able to 'stand alone'. Someone looking at 4D2A who (like me until an hour or two ago) was unaware of 4A3 would have no reason not to believe that it (4D2) was applicable to PVC T+E. To my mind, that is not satisfactory. The Table already has one note in the margin relating to flexible conductors and it would have been only too easy to add a second not indicating that 4D5, rather than this Table, should be used for flat PVC T+E.

Kind Regards, John

 

[ban-all-sheds]

There is no doubt in my mind that PVC T+E satisfies both of the descriptions given in that row of the table, both the one which identifies Tables 4D1/4D2 and the one which identifies 4D5. If they had wished the former of those descriptions to have excluded T+E, they could very easily have said so, but didn't.

And there is no doubt in my mind that that row in 4A3 is telling you to use 4D5 not 4D2.

 

[JohnW2]

And there is no doubt in my mind that that row in 4A3 is telling you to use 4D5 not 4D2.

That's what it should say but, as written, there is nothing about the wording which prevents one using 4D2. In any event, as I said, 4D2 should be able to 'stand alone' for those who have not looked at (or aren't even aware of) 4A3...

... It would have been SO easy for them to to add "not including flat PVC T+E - see Table 4D5" (in the title, or as a Note) to 4D2A.

Kind Regards, John

 

[PrenticeBoyofDerry]

That would depend how long your entire professional life extends back, as already mentioned table 4D5A covered flat T&E in 16th editions.

[I presume you mean 4D2A] ...

No! Flat cable with CPC, as stated in table 4D5A, the only table I am aware this is mentioned, therefore applicable to the standard T&E.