In article ,
Andy Wade writes:
John Rumm wrote:
[Lampholders]
Placing "out of reach" is acceptable in many circumstances.

That isn't the measure (as defined in BS 7671) being used here though,
to avoid shock by direct contact. The measure is still "protection by
barriers or enclosures" [412-03-xx] with an assumption that the
barrier/enclosure is completed by the lamp itself. Reg. 412-03-04 in
general requires that enclosures can't be opened without the use of a
tool, or some interlocking mechanism to disconnect the power first, but
this reg. goes on to make specific (historical) exemptions for ceiling
roses, pull cord switches and lampholders.

As well as the points you made, another is that the area of skin contact
with the live terminal in a lampholder is too small to give rise to a
shock current likely to be high enough to prove fatal.

I searched for any records of electrocutions from an open
lampholder, but could find none for this country. Edison
Screw holders do seem to have caused some in other countries,
almost certainly when the supply wasn't polarised and the
outer screw was the live, including the bulb cap. More
modern ES lampholders don't make contact with the outer
screw contact until the bulb is screwed right in, but in
countries where they've been in use for years, there are
older ones where the screw thread is also the contact, so
they're live all the time and the bulb cap becomes live
the moment it touches the lampholder.

--
Andrew Gabriel