I have posted a piece here which is also on the TT topic, but is more general and I think a new thread would be better. Your voice is heard. See below.
That is a good and fair question. There was very considerable pressure to "do something" from the London fire brigade who had seen a lot of incidents. It was never ascertained the complete cause of the fires, they were loose connections, but why did they occur? Fire investigation of small non-fatal fires is not good in a number of ways, but a consensus idea was that they may have been related to smart meter installations in some way, as the installers moved the tails around, but did not or actually were not allowed to check the connections for tightness! Whether this is true or not was never investigated. The decision was therefore to make non-inflammable enclosure a regulation (although some aspects are still not very clear, eg external RCDs in TT installs). A metal case immediately makes the CU identifiable, is hardly more expensive, and much more fire-resistant. The CUs without the fire retardant, are difficult to identify, and the problem seems to have largely gone away. I have tried to follow up on the terminal problem with tails cables, suggesting that a crimp spade type terminal would improve the terminations, with a couple of manufacturers, but so far none have taken the idea up. I hope that is helpful and sufficient to satisfy the feedback you would like.
That is a good and fair question. There was very considerable pressure to "do something" from the London fire brigade who had seen a lot of incidents. It was never ascertained the complete cause of the fires, they were loose connections, but why did they occur? Fire investigation of small non-fatal fires is not good in a number of ways, but a consensus idea was that they may have been related to smart meter installations in some way, as the installers moved the tails around, but did not or actually were not allowed to check the connections for tightness! Whether this is true or not was never investigated. The decision was therefore to make non-inflammable enclosure a regulation (although some aspects are still not very clear, eg external RCDs in TT installs). A metal case immediately makes the CU identifiable, is hardly more expensive, and much more fire-resistant. The CUs without the fire retardant, are difficult to identify, and the problem seems to have largely gone away. I have tried to follow up on the terminal problem with tails cables, suggesting that a crimp spade type terminal would improve the terminations, with a couple of manufacturers, but so far none have taken the idea up. I hope that is helpful and sufficient to satisfy the feedback you would like.
