Rod Speed wrote:


And all you have to do to eliminate the electrocution problem is to ensure
that the outer only ever gets connected to the neutral, not the active.

Yes - but that will never happen in many countries. Even in the UK, where
polarity is (or should be by regulation) assured, and wiring the phase to
the centre pin on an ES fitting is mandatory - you will still get polarity
cock ups.

Case in point - my son got a bit of a belt from such a fitting in China. I
do not believe they maintain polarity, and RCDs are a relatively new
idea[1]. Lucky he was standing on the bed and possibly leaning against the
wall as opposed to holding onto a water pipe.

[1] though to be fair to the Chinese, last time I had a quick shufty around
a new build flat, the CU was stuffed full of RCBOs and put a typical British
board to shame - I really have no idea if that is mandator or if the owner
had just paid a lot to a top notch sparky - but given their liking of
electrode heater shower units plugged into sockets near (or in!) the shower,
I bloody hope it is required now.

The actual answer is as I mentioned before, to use an insulating thread with
the outer contact near the bottom so the bulb shell cannot become live until
more or less fully screwed in - it's about the only fully idiot proof
method.

Even BC holders, which as Andrew mentioned have a surprisingly low injury
rate, modern *decent* ones only make the contacts live upon insertion of the
bulb (Hager-Ashley)[1] - but this is not a requiremnet

The Ashley ones do this by rotating a plastic shim using the side prongs
during the insertion twist - which is hard to accidently defeat.

This was a problem with the first CFLs with iron ballasts, but
it's not a problem with most current lamps which are much lighter.

The big PAR38s ares still around and quite commonly used in domestic
situations.

Still plenty with the heavy glass too.
--
Tim Watts