"Ignoramus25850" wrote in message
...
On Tue, 06 Sep 2005 11:24:10 -0400, Steve Spence
wrote:
Our 50amp transfer unit only switches power from grid to generator after
30 seconds from when it sees power from the gen.


http://www.green-trust.org/wiki/inde...ransfer_Switch

What I am describing is a manual switch. The user would have to
perform the following steps manually:

1) Turn off the main breaker.
2) Turn on the mechanical switch for DC input circuit to the relay,
which becomes possible only if the main breaker is off.
3) Turn on the generator (could be done at any other time in this
sequence)
4) Press the START button on the start/stop switch.

At any time, if the interlocked mechanical switch is turned off, the
contactor would open and electrical power would no longer be supplied
to the house from the generator. The interlocked switch must be in the
off position for the main breaker to be turned on.

I caught your concept of a "manual transfer device".

Where I live there MUST be mechanical interlocks. That means if either
breaker is forced into the other position BOTH breakers change state at the
same time. I am talking about internal switching from one device to
another. Steps 1&2 would have to happen with one operation.

The utilities used to have a requirement for "visible blade disconnection" I
got into a situation where no one made a 4000 amp visible blade disconnect.
So they changed the spec to mechanical interlock.
I will bet that your contactors are not 'service rated'. Do you know the
fault current your generator is capable of? How about the serving utility?
10000 amps is pretty common I have seen places where special circuit
breakers were needed because the fault current was over 10k.

Call the local jurisdictional authorities and talk to them. I do not know of
a utility that would allow what you describe. I am familiar with the
utilities in 4 western states.



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