On 21/03/2014 10:27, Dave Plowman (News) wrote:
In article ,
Nightjar wrote:
even 50v which one of the Cambridge colleges had in 1960 - the town
having a 200v supply. It was soldring irons that suffered really
badly if you had a 240v element on 200v.


25v and 50V are still common as working lights on machine tools,
although modern ones tend to use 12V H1 halogen lamps, presumably as
they are readily available for cars.

Low voltage filament lamps survive vibration (and knocks) rather better
than mains ones - and 12v car ones perhaps best of all.


I think the main motivation, certainly with the exposed lamp types, is
that ELV won't kill you if the coolant stream goes in the wrong place.

Colin Bignell