I've never argued that it could be. As far as the legality is concerned, as in compliance with the "reasonable provision" requirement of Part P, it comes down to two questions, although I don't expect straight answers from you:
1. Do you dispute that according to official guidance for Part P, "in the view of the Secretary of State" an installation which complies in all respects with BS7671 is considered as meeting the legal requirements of Part P?
No, I do not.
Do you dispute that an installation with mixed colours is less safe than one without and that continuing to use old colours does not make the work you do non-compliant with BS 7671?
2. Assuming that the appropriate warning label is applied, do you dispute that an installation in which brown/blue cable has been used to extend an existing circuit wired with red/black complies with BS7671?
No, I do not.
Do you dispute that such an installation would present greater hazards to someone maintaining or altering it in the future than one where the colours had not been mixed?
If the answer either of the above questions is yes, then please explain why you think so. If the answer to both questions is no, then I don't see how you can possibly claim any sort of illegality.
1) There is no regulation which prevents you from using red and black cable today.
2) Using R/B cable to extend/modify an R/B installation is saf
er than using new colours.
3) If you have no
reason to insist on using the new colours, if you can
reasonably use the old ones then choosing not to do so is not a reasonable course of action.
4) Unreasonably making an installation less safe than you could otherwise reasonably do does not qualify as making reasonable provision to protect etc etc.
Can you really think of any other example where a local authority would accept "I don't have the right material to hand" as an acceptable excuse for carrying out work which does not comply with the appropriate part of the building regs?
Again you refuse to recognise the presence of the word "reasonable", and again you insist that if I'm right the theoretical availability of something to you would make its use mandatory, whereas what I'm saying, over and over again, is that you must consider a reasonableness test.
I'm not saying it would be reasonable to expect me, or anyone else, to do that.
Then why, when all along I've talked in terms of it being reasonably available to you did you dream up the scenario of searching eBay and paying some ridiculously inflated price for 3 or 4 yards of old-stock 2.5 T&E because it was "available" to you?
You don't think it would be reasonable to expect you to do that in order to have the cable available,
I've not suggested it would be reasonable - my whole argument hinges around what is or is not reasonable behaviour and yet as soon as I talked about the cable being reasonably available to you you put forward that ludicrous argument about "availability" without any regard to
reasonable availability.
Why?
I was asking you to explain how you defined "available."
I originally said if you
have it available. Not "could make it available quite easily", or "could get some if I tried".
... if you have NOS pre-harmonisation cable available ...
...What I said was that if you have got some NOS pre-harmonisation cable available ...
... if you have old-colour cable in new condition available ...
But what if I don't have any suitable red/black cable stashed away?
Then it's
not available to you
But it seems that you are unwilling or unable to use a reasonable definition of "have available".
I still don't see it as reasonable for you to believe that extending with brown/blue can be illegal just because you happen to have some red/black cable laying around when (a) it complies with BS7671 which in turn is deemed to be compliance with Part P, and (b) you acknowledge that an installation which ends up exactly the same will be perfectly legal if no red/black is easily available.
To claim that of two identical installations one is legal while the other is not is absurd. How the installation arrived at having mixed cables is irrelevant (besides which, nobody is going to know whether or not you had some suitable old cable laying around anyway). The building regs. are about meeting a certain minimum acceptable standard, in this case making "reasonable provision" for safety, not about whether of two choices available you opted for the better one.
You have a choice of two actions, A or B.
A is safer than B.
A is not harder to do than B.
A is not going to take you longer to do than B.
A is not going to cost you more than B.
A is not prohibited by any legislation or regulation.
You have no
reason to avoid doing A.
Yo have no
reason to prefer doing B.
Giving all that, deliberately choosing the less safe option for
absolutely no reason at all is not reasonable behaviour. It is
unreasonable.
No, but then neither is it reasonable for the law to demand many of the things which it does demand (e.g. paying over £100 to the local council to add a socket in my own kitchen), so I don't see how that comes into the argument.
It comes into it because we are talking about the law requiring you to behave reasonably.
So
you don't think it would be reasonable to scour eBay,
I've never suggested it would be reasonable for you to scour eBay, in fact I've never suggested that it would be reasonable for you to make any effort to acquire such cable, and you don't think that it would be reasonable for the law to require you to do it.
And yet because
some laws are deemed to be unreasonable you decided to throw all reason out of your argument and suggest that we can't imagine any laws being reasonable.
I think it's your perverse way of trying to interpret it which is the problem, just as in that earlier thread.
Why is it perverse to regard a decision to reduce safety, made without any basis in reason, as being unreasonable?