Installed a couple of flush ceiling lights for a customer yesterday.
Metal fitting was earthed by the usual method of the chocky block screwed to a tab, but they also had an earth wire attached to the ceiling bracket.
Since said ceiling bracket is screwed to a plasterboard ceiling - whats the point of doing that?
It was quite handy as it held the light while I wired it up, but I don't think that's why it was there.
Lights came with that heat resistant tubing and the instructions stressed that it must be fitted to the mains cables. So I did.
The three pairs of wires going from the chocky block to the lights didn't have any heat resistant sleeving at all. The mains cable was mainly inside the ceiling anyway.
Surely any excess heat would affect all the wires, especially the three pairs nearest the bulbs?