"Bill Noble" wrote in message
...
note that the "one side live all the time" is pretty much unique to the
USA, whose standard 220 is really based on a grounded center tap neutral -
most other countries have a 220 that has a neutral leg and the hot leg is
220 above it, and the neutral is nominally at ground. So, in some other
country - say the UK, a single pole switch on the hot lead would eliminate
any "live" voltage past the switch.


"Doug Miller" wrote in message
...
In article , "Bill Noble"
wrote:

actually, a single pole switch will work,

"Work" in the sense that it will stop the device from operating. But not
safely...

but one side will stay live all the time

.. for exactly that reason.

so a double pole single throw switch is preferred

If by "preferred" you mean "required for safe operation" then I will not
disagree with you.



aaah, no, my point was that in my experience that there are other countries
in the world, and that sometimes residents of those other countries might
read this news group, and that it is only common courtesy to suggest how a
discussion that is unique to the peculiar way the USA does things might
differ if it were applied to their situation. Because of our lawyer rich
society, I have offered no opinion on the safety or legality of any switch
configuration, I have merely offered specific information on the way that
power is supplied world wide and how a motor might possibly be controlled by
a device capable of interupting said power. Any application to actual
electricity is at the risk of whomever elects to be in the presence of said
electricity. Many countries have recommended configurations for such
devices. Some countries even have laws and regulations governing the
employment and application of such devices. It would be incumbent upon the
user to establish saftey, legality, permitting, and to comply with all
local, national, international, galactic, and intergalactic regulations that
might possibly apply to their situation and to make said determination after
proper consultaion with those fully authorized and empowered to supply said
determination.

I hope that the above elucidates my position with respect to possible
confgurations of power supplies and the means that one could in theory use
to supply or interrupt them.