The datasheet states "13 A non-rewireable plug". How is it non-rewireable? Shouldn't there be a screw on each of the pins to secure the wire inside? Or are the connections crimped instead of screwed on? Thanks.
Conditions for Use:
.....
An altitude not exceeding 2,000 metres above sea level
Bearing in mind that these plugs are only used in the UK and the highest point in the UK is the top of Ben Nevis (which just tops 1,000 metres) We're not going to need altimeter are we?
But it has got me wondering. What would happen if aircraft started using these types of sockets and someone was foolhardy enough to use it at 2,001 meters above sea level?
I'd always choose thermosetting plugs, not thermoplastic, as they will not
melt. Note the ludicrous temperature requirements on that plug(*).
These MK plugs are the nicest you can get - you cut and strip the wires to the same
length and the cord-grip is a simple push-in one, no fiddly screws. The body is
thermosetting urea-formaldehyde and will survive at much higher temperatures than
cheap nylon plugs.
(*) "An ambient temperature in the range -5°C to +40°C, the average value over 24 hours not exceeding 25°C" - basically the nylon plug is not rated safe to use during a heatwave
(yes, we sometimes get heatwaves in the UK).
Parts of India and Pakistan, where this type of plug are also used have elevations over 8000m
ARE THEY MAD. That's so dangerous 
No, they need electricity and use fuses. A flashover inside a plug is dramatic, but no-one
dies. Flashovers can happen at sea level too, I've witnessed one and it took out 3 fuses
simultaneously and coated the inside of a 4-way mains adapter in condensed copper. All it
took was unplugging a plug from a live socket.
What is the mechanism that causes that ?
Sudden disconnection of inductive load ?
Boardburner2:
What is the mechanism that causes that ?
Sudden disconnection of inductive load ?
Not necessarily the local load.
Ridiculous surges on the mains due to poor infrastructure (substations etc.)
Typical arse-covering "Conditions for Use:". Doesn't mean the component cannot or should not be used outside those conditions, but it protects the manufacturer from legal action.
The "non-rewireable" description is quite deliberate - what is not quite clear from the illustration is that it is supplied with "one way" screws!
The "non-rewireable" description is quite deliberate - what is not quite clear from the illustration is that it is supplied with "one way" screws!
Ah yes. These things are a real PITA. They are also sometimes found on things like power adapters etc... So annoying.
Easily fixed with a dremel grinding wheel.
Easily fixed with a dremel grinding wheel.
Not if the heads are recessed into tubes over an inch deep. By the time you've got down to them you've completely destroyed the housing.
Boardburner2:
What is the mechanism that causes that ?
Sudden disconnection of inductive load ?
It was a laptop PSU, not highly inductive. My speculation is that the normal small spark
on unplugging just happened to fire an ultra-tiny piece of metal across the gap from
live to neutral and the plasma trailing in its wake became a conduction path for the full
mains, the bang was very loud and peak power in the flash would have been tens of kW
I estimate.
Such flashovers can happen for various reasons, damp getting it, insects crawling in...
Mains wiring inside equipment is normally fully insulated / shrouded to prevent such
things, but re-wirable mains plugs and sockets are a cruder environment.
Moulded mains plugs thus have an obvious advantage... However there was a scare
many years ago about one brand of imported molded UK plugs where the quality was
so poor they sometimes shorted internally and posed a fire-risk - so there are also issues
with making something inherently impossible to inspect for defects.