Bearing in mind my involvement with extension leads have covered 60 years including lots of portable work including installing temporary power for event purposes. Also bear in mind this covers just about every connector that's been available, every size of BS546 2-30A BS73/372 (2 & 5A), BS196 15-60A, BS4343 16-125A, Shuko, etc. None of those have I/we ever felt the need to 'protect'. I use he word protect in the absence of thinking of a better word. Generally I wouldn't expect to be running leads with BS1363 plugs around a site in the way I would any other types as they are simply too fragile and right from the beginning of them being in common use have proved to be more trouble than any other product, instead we will use adaptor cables to something else (these days usually BS4343 or until say 10years ago BS546 15A) which are stored and transported in smaller quantities to protect them. Until about 10years ago I used to carry an original Wylex design 13A fused plug adaptor cable which predated the MK style, and still stock a BS1363 clean/clear earth adaptor cable.
Apart from BS1363 items I'll be very happy to run full CCC indefinitely with all of the above products and I've known many on ocassions to be running at well above their design without apparent fatgue, as an example a local theatre ran 8x 500W lamps on a Strand dimmer plugged into a 15A socket. (8x500/240>16A) and they would often be lit for a 2-3 hour event. Just before I started working there they upgraded to 1KW lamps, simple in it... just change the lamps (8x1000/240>32A) and the loadmaster to 30A, nearly a year later we were making some changes and I noticed the 15A plug and socket, believe it or not there some discussion on whether to leave it alone.
Such work all too often involves assisting users with what they plug into my kit and apart from adaptors the problem is most likely to be faulty BS1636 plugs which all to often damage my sockets and of course it's always my socket that has bent their plug. A bent pin on something like an urn very quickly overheats due to lack of contact area!
I have some BS1363 extension leads which are 50 years old and serviceable but like triggers broom probably not alloriginal connectors (I dare to admit I recently used one without sleeved pins and afterwards reluctantly changed the sound plug), some BA546 leads 60 years old with original unsleeved connectors and BS73/372 with fig8 or twisted flex of 60-70 years old.
So far I have deliberately avoided mentioning the 'flex connector' styles, which I have used vast quantities of but mostly for loudspeaker use, for several reasons; mainly they are simply not fit for purpose as the spacing and pin dimensions were never standardised, typically different makes would 'jam' together or be intermittant and the cord grip arangement (if there was one) far from satisfactory.
Anyway my ramble is based upon the difference in performance and reliability between BS1363 and all the other BS compliant connectors, my conclusion goes 2 ways; either BS1363 is not adequate (or not adhered to) or all the others which predated it are vastly over engineered. Bearing in mind the safety aspects and hazards involved, I'll opt for the former option. This is just my opinion based on a lot of years of repairing faults, others experiences may differ, but the tile of the thread and some replies do seem to indicate a similar opinion.
