On Mon, 13 Oct 2003 12:35:34 +0100, Chris Wilson
wrote:

I am looking for advice on the easiest way to wire up a modified
electrical distribution panel here at home, to allow a generator to be
fired up and take over power supply to the house during one of our fairly
frequent mains failures. Ideally I would like a self powered contactor to
isolate the mains input to the board and make available a socket into
which the generator output is left plugged. Once power is re-established
from the mains this socket would be automatically isolated and the mains
takes over the running again. I need to (obviously...) avoid the scenario
where both mains and generator are connected at the same time! I would
like it automated so if I am not here the wife only has to check no
excess loads in the house are still on, albeit not working due to power
outage, go outside and start the gennie, with no switches to fiddle with.
I intend to have an LED on the inside fuse box to allow her to see when
the mains is back, so she knows when to turn off the generator. Possible?
Schematics? Web site showing this? I am sure it must be a fairly common
thing for people living with iffy mains supplies.

Thanks. I am in the UK. Mains is normal 240v single phase.

In the States, these devices are called "transfer switches" and a
Google search will show many designs. They are available in manual or
automatic versions, with the manual being cheaper. They are basically
a large DPDT switch. The automatic versions include power sensing and
delay hold functions.

If your generator is not an autostart model, then a manual transfer
switch is normally used. Autostart generators are installed with
automatic transfer switches.

The one used with my 25KW autostart generator is from PSP Products.
Their line of transfer switches can be seen at
http://www.pspproducts.com/body_transconnect.html . This page also
includes some introductory material that may help you understand
transfer switching.

I'm sure you can find something similar in the UK.


Jack Smith