On 21/03/2014 17:41, Johny B Good wrote:
On Fri, 21 Mar 2014 08:53:14 +0000, Nightjar
wrote:

====snip====

However, while early lamps were made to exactly match the supply
voltages, a necessity with the poor quality of early filaments,
latterly, if you looked closely at the markings on the lamps, one that
was sold for 220V could be exactly the same as one sold for 240V. People
were so used to buying lamps to match their supply that it was simpler
to put the same lamp in different packages than to try to educate them
to the fact that you could run a 240V rated lamp on 220V, but not
necessarily the reverse.


I'm afraid to say this, but that last paragraph is basically a load
of bull****...

I would pass that on to the curator of the Electricity Museum, who
showed me the markings and explained the situation, but he was a retiree
when I was in my 20s and he is now long gone.

Colin Bignell