Charlie E. wrote:
On Wed, 24 Feb 2010 12:34:25 -0500, "Jon"
wrote:

I'm trying to wire a transfer circuit for a generator.

The generator will be located in the barn. The electrical service is at the
house. Two 120vac wires and a ground go to the barn. There is *one* unused
wire from the house to the barn I can use for a signal circuit.

When the power goes off at the house, I need to disconnect the service to
prevent backfeed and activate for generator power to both the house and the
barn. When the service power goes on I need to disconnect the generator to
avoid damaging it and restore normal service to the house and the barn.

I have,

*one 240vac 60 amp dpdt mercury relay
*two 120vac 60 amp 3pdt relays.

Any ideas?

Jon Giffen

First, hire an electrician! There are safety issues involved with
stuff like this that leave you open to liability questions otherwise.

@#$% modern tort laws!

Your personal liability varies by the culture of your state -- the two
examples I know if are Kansas and Oregon. In Oregon, if a neighbor gets
drunk, breaks into your yard, and drowns himself in your kid's wading
pool, then you'll get sued and it might succeed. In Kansas (unless it's
changed since my sister lived there), if a neighbor kid goes swimming in
your backyard pool without permission and drowns himself the jury will
shake their heads and tell the kids parents they should have kept a
closer eye.

snip

--
Tim Wescott
Control system and signal processing consulting
www.wescottdesign.com