I have this generator:

http://igor.chudov.com/tmp/onan/Diesel/

I bought these interlocks on eBay:

http://cgi.ebay.com/ws/eBayISAPI.dll...m=300106024488

They are actually quite large, the photo does not do them justice.

My plan is to place interlocks so that either the generator's
disconnect is closed, or the main panel breaker is closed, but never
both.

That's what they were designed for, if it is unclear to anyone, I can
explain it in more detail, or see: http://www.kirkkey.com/index.html

I would lock up another key (they are keyed alike) in my safe so
that its use cannot defeat this system.

I believe that this arrangement fully satisfies the rule that a
mechanical interlock device should prevent both sources of power from
coming in contact.

Any comments?

i