On Sat, 19 Nov 2016 16:33:00 +0000, wrote:

[snip]

The early Hoovers would have been used on DC supplies as well, any one
know if any area had DC sockets with an earth?

Drifting from the topic (as is often the way) it is interesting you
should mention DC supply. Was this commonplace in the UK (I know it
was in New York - battle of the currents) and if so when did this
change?

In our old house some of the sockets had very heavy springs and I
remember being told at a young age this was because they were designed
for DC (to prevent arcing). I have Googled many times since and been
unable to find anything on any 'AC switchover'. I was also told it
was related to the closure of the municipal generating station (for
the trams) and introduction of the National Grid but again I can find
no support for this..