OTQ, how do folk feel about screw terminals bearing down on tinned cable ends?
I reserve the right to do it when persuading fragile skinny cables that aren't carrying any current to remain unfrayed for the time it takes to do up the screw (usually low-voltage stuff like telecoms), but consider it a Mk 1 Bad Idea on mains wiring. On the other hand, it probably made sense for appliance manufacturers to do when they were sold without a plug, as muggles doing a shoddy job at stripping/twisting wire is probably a greater risk than plastic deformation of solder over time.
The correct solution would be terminals with a clamping plate, and/or lugs or bootlace ferrules on the cable. Not sure you can do either inside a BS1363 plugtop?
just for fun I have used bootlace ferrules inside a 13A plug but it was a bit fiddly and it felt like overkill. Given a free hand I still prefer the old MK 13A plugs with proper post terminals inside them. At one time you could get those with a switch in too; all very sensible.
One of my former colleagues reckoned that the tin in the solder would be subject to stress/temperature induced twinning and that was the thing that allowed the screws to lose their grip over time. Against that screws could (even without a plate or a ferrule) probably be tightened more, and have a larger contact area in the joint to begin with. Swings and roundabouts I suppose. When appliances were still shipped without plugs, often the wires would be bared for about 3/8" length with just the tips tinned. I always suppose that the idea was that the bared wire was doubled over before the screw was tightened onto the bare copper.
However I don't ever remember seeing a set of wires which were cut to length for safe 13A plug wiring. I consider it a failing of the design that if it is wired in the usual (casual) fashion, i.e. with nearly equal length wires, then the last one to pull out of the plug if the wire sees a hard tug is the live wire. Potentially this leaves the appliance unprotected and if the neutral wire is both disconnected and exposed by being pulled out of the plug, live parts are then exposed.
I have often wondered why they didn't route the live wire the long way round the middle of the plug, so that it would be first to get pulled out, rather than the last. Possibly there is a very good reason I have not thought of.
cheers