Had a chat with my fireman brother recently retired and now works as a trainer for fire services and other establishments, and he says from statistics and his own experiences , the majority of electrical fires are and generally always have been caused by faulty appliances, old installations, fake/poor quality components, overloaded outlets , poor workmanship /loose connections and damage to electrical components accidental and vermin related in that order
His opinion. ..
He said it would make more sense to do something preventative to real causes of electrical fire such as educational campaigns perhaps even going as far as compulsory testing/inspection and possibly pat testing of domestic appliances for insurance purposes at reasonable timescales,
Of course this wouldn't necessarily solve the problem as many couldn't afford the costs involved, in testing and remedial works,
So he thinks this is an easy way for the IET and others to look proactive with the costs borne by others, thinking this won't affect the consumer too hard other than testing costs, which of course is rubbish, there will be a manufacturing cost passed down to joe bloggs for any new Cu's
Changing CU construction to metal will have little effect on fire statistics even long term as there are millions already installed anyway especially in Europe and statistically few fires caused so why introduce a rule like this, much better to make manufacturers use a self extinguishing plastic material which can be injection moulded and improve the terminal quality as it would be the most cost effective way forwards.