10.7. It should be noted that the protective measure double or reinforced insulation is only applicable to electrical installations or circuits therein that are under effective supervision in normal use to ensure that
no change is made that would impair the effectiveness of the protective measure (regulation 412.1.2). Domestic and similar premises falling within the scope of this Guide cannot be considered to be under effective supervision.
I think this is a non-argument?
I genuinely think there are flaws whichever way we turn on this if a rewire isn't affordable at that moment in time. I also think we'll never all agree!
In a nutshell do we say that even though the old regs allowed omission of something that the new regs require, we should avoid making it a bit safer because another new reg uses "adequate supervision" as one example of how to make sure the installation isn't modified, even though the best practise guides suggest making it a bit safer as the 2nd choice last resort (3rd choice being risk assessment)
Modern regs require things old regs didn't. Modern regs also clearly say that older installations to older regs aren't necessarily dangerous. We say the regs are retrospective often enough. So anyone inspecting makes a judgement call on this and says not complying with this newer reg requiring a cpc makes it potentially dangerous.
We then have dear BPG4 relating to domestic eicr's pointing us to BPG1 regarding this issue, which starts off talking about homes not needing a cpc in lighting circuits once upon a time, goes through the hoops of what to do, and finally says in 10.7 '
by the way don't do this in homes'.
But then read on - even more amusingly it goes on in 10.8 to say what to do if you reconnect one:
10.8. Subject to the recommendations of Section 10.3 to 10.5 (NOT 10.7) of this Guide being met, where lighting circuits having no protective conductor are connected to a new consumer unit, it is strongly recommended that a warning notice with black letters on a yellow background should be fixed on or adjacent to the consumer unit
Bottom line for me, if a month after I was at a property the live dropped out of a fitting and someone died changing a bulb I'd probably wish I'd ignored one interpretation of 412.1.2 and I'd put a class 2 fitting in. If they change it back, good luck to them, but I'd sleep better knowing I'd done my bit by explaining why a rewire is needed, and doing the best for them in their current situation.
Finally, genuine question - Even though RCDs are deemed additional protection, would having one on the circuit do anything to appease 412.1.2 which starts off "Where this is to be used as the
sole protective measure....."