Two electrical devices, one switch
 

I would like to control a single pump from two power sources on a
mutually exclusive basis. That is, the pump is connected to either the
grid or a generator, but not both at the same time. Would a standard
"3-way" type switch do this? If I understand correctly, such a switch
is a single pole, double throw switch. If I hook a hot (black) from
the generator to one brass screw on the switch and the other hot (grid)
to the other brass screw on the switch, run a neutral (white) from the
silver screw on the switch to the hot side of the pump (recoded black
at the pump end), and connect the neutrals (white) from both the grid
and the generator to the neutral pole on the pump, will it work? Then
when I throw the switch one way, power goes from the generator to the
pump; throw the switch the other way, power goes from the grid to the
pump, but at no time can the generator or the grid back feed each other
if they are both hot at the same time, nor can the pump be fed hot from
both the generator and the grid at the same time?

grid------------hot(black)-------------------switch hot A

generator --------hot(black)--------------switch hot B

grid and generator----------neutral(white)-----------------switch
neutral

grid--------------neutral(white)---------------------pump neutral
generator------neutral(white)---------------------pump neutral

switch neutral(white)---------------------------------pump hot(recoded
black)

Then, switch thrown one way completes grid circuit to pump and
disconnects generator circuit to pump; switch thrown the other way
complete generator circuit to pump and disconnects grid circuit to
pump.

Have I got it right?

Bruce Rieck

Two electrical devices, one switch
 

If that is a 120V circuit, yes, a three way switch could switch a
power source. Note, however, that regular three way switches are not
guaranteeing that one connection would be interrupted before another
connection is made (break before make). So switching may momentarily
connect your generator to the grid, with possibly disastrous results
(that momentary connection may possibly weld instantly if both
generator and grid are connected together while the grid is live, or
electric current could be sent to the grid when relair workers are
working on lines, etc).

It is not a good idea.

You should look for something else. I would just make two outlets, one
powered by the grid and another powered by the generator, and would
plug the pump into appropriate outlet.

i

Two electrical devices, one switch
 

Thanks, I'll think about that. Do you know if I can buy a 120V break
before make 3-way switch?
Bruce

Two electrical devices, one switch
 

Two electrical devices, one switch
 

wrote:

You can find what you want he
http://www.green-trust.org/generator/genny_install.htm

It's called a transfer switch. Don't try and use some do it yourself
toy. I assure you your local power company workers will not be happy. It
is really IMPORTANT to do this right.



--
Joseph Meehan

Dia duit