In article ,
Tim Watts writes:
Rod Speed wrote:

Tim Streater wrote
Tim Watts wrote

And in the old days, we mostly only had BC fittings to worry about...

Yes, what is it with this screw-in **** that seems to be creeping in?

Its basically a better design.

Unless you have metal casing forming the main socket screw thread, and you
use it in a country where polarity is not guaranteed - eg touching the lamp
neck (eg whilst unscrewing) gives you a shock.

This results in some electrocutions (IIRC, about 2 in the US per year).
No one has managed to find any record of an electrocution from a BC
lampholder by touching the exposed live pins - you probably can't get
a good enough contact even with wet hands.

Of course, modern designs use an insulating thread and a contact near the
base - but BC have never had this problem.

Occasionally, I have found ES resistant to unscrewing resulting in shearing
the bulb base.

Another common problem with US ones is the whole holder unscrewing
and either coming apart, or jaming because the two part lampholder
has a finer screwthread than the lamp base thread. The EU 40mm
mounting ones seem much less prone to this (many have a ratchet
which prevents the lampholder parts ever being unscrewed).

ES grips the lamp better which means it can support heavier lamps
at strange angles, which the pin springs in a BC holder can't.
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.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]