On Mon, 9 Jan 2012 19:14:21 +0000, (Fergus
McMenemie) wrote:

Folks,

I recently replaced the shaver socket in the bathroom, and boy ... do I
feel cheated. The old unit had two outputs one labeled 110v the other
220v with an external switch to select one or the other. I have both an
electric toothbrush and an electric shaver and I was fed up having to
keep track of which was being charged and for how long. So I replaced it
with a 2 gang MK shaver socket from B&Q which had two outputs and no
switch, one marked 110 and 220. Since both my devices will run on either
110 or 220 I intended to plug in both simultaneously and it would not
matter about the different supply levels.

However it turns out the MK unit was switched, it had an hidden internal
mechanism operated by insetting a plug. Only one of the sockets can be
used at a time. A real pain. This was not marked on the packaging
anywhere. I phoned MK and they gave all kinds of guff as to why things
were the way they were. Interestingly the support guy did admit that
these devices were designed decades ago and were not intended for
continuous use, even if this continuous use only involved having to
support trickle chargers. Some shaver sockets tended to overheat and
would cut out, if say a shaver was left continuously plugged in! This
has apparently been fixed.

However my question is has anybody hacked these units to allow both
sockets to be used simultaneously? I am interested in any thoughts as to
wiring the transformer's output to both sockets, and bypassing or
disabling the switch. Assuming the transformer only has one secondary
winding which is tapped to provide the 110v output. Should I use the 110
or 240 winding?

Thoughts?

I would have been surprised if the two sockets could have been used
simultaneously and I would have assumed there would be a regularity
requirement that they can't.

Cue someone who knows.

If they did work the way you wanted then it could be a (roughly)
centre tapped secondary winding to give 110 and 240 or it could be two
separate windings which with an in phase link in place would gibe you
a 350volt supply in your bathroom. I know it's unlikely to happen by
accident, but still.
The same could happen with multiple isolated outlets near to each
other, I wonder if there is a prohibition about this?

--
Graham.
%Profound_observation%