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Re: OT (most likely) strange modem disconnection when using USB drives



Frank Cox wrote:
> 
> I don't know enough electrical theory to explain this stuff.  I have seen an
> electric meter still running at a  closed-down building with all of the power
> shut off at the main breaker box -- we discovered the problem when we got the
> next power bill.
> 
Leakage to ground. It can be cause by a bad appliance plugged in but
is usually because of a bad underground cable. If you have a long
enough run, you can also short the hot connector to ground without
tripping the breaker. (Try string 3 100' residential grade extension
cords together, and short the end - great way to free cords frozen
in the snow.)
> 
> There are also some weird effects that can be created by hooking devices from
> different circuits together.  I know that the electrician here had to do some
> fancy stuff to make my air conditioners and the zone valves on my hot water
> heating system work properly as they run on different circuits.  It ended up
> that there was no easy way to use a single thermostat in the rooms, even though
> the devices would never be on at the same time and even though the thermostats
> physically switch from "cool" to "heat" so you wouldn't think there would be a
> conflict.
> 
He should have been able to get them on the same phase. If not, a
simple relay will do the trick. A bigger problem may have been
different control voltages between the two, though I would expect
24VAC to be used. (Unless you have a window air conditioner.) You do
have to label things so that the next person know there are more
then one circuit involved. (In more complex control systems, we
usually used orange or yellow wire for circuits switched in one
cabinet that are powered from another one.)

Mikkel
-- 

  Do not meddle in the affairs of dragons,
for thou art crunchy and taste good with Ketchup!

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