I went a little overboard with my system. But then, I usually do everything electrical a little heavy handed. My generator distance is unknown, but by wire is around a hundred(100) feet. I have two residential buildings.(in an old neighborhood) One is the residence, the other is modified to be a shop. The metal shop in one side and wood shop in the other. Plus the various hobby shops in assorted corners.
The two buildings are on 50 foot lots. On the "shop" side, there is a barn some 60 feet behind the "little house" (Deep lots) The generator resides in that barn. There is a 100A submain from the barn to the shop. Welder and other heavy loads there. Then there is a 100A submain from the "big house" to the "little house". This feeds the shop, the metal working machines, wife's wood machines, my model trains, and the like. In essence, I have a submain feeding another submain. All are four(4) wire circuits, a legal requirement in my area. Neutral and ground as seperate conductors. Read
http://www.hudsontelcom.com/ A little down the page is "Home Shop Electrics", an extensive (50+ ppg PDF) writing on the subject. Most of it won't apply in this instance, but should provide some insight to the subject.
For basic operation, with a 6.5KW genset(6500 watts) to back feed into the big house, there are numerous circuit breakers between the incomming line and my genset. The established protocol for dealing with an extended power outage is to (1): Trip the main breaker on the incomming line. (2): Verify main breaker is off. (3): Open the breaker to the shop (4): THEN proceed to the barn and start the generator. All of this is
to assure, absolutely, that the generator will not backfeed into the pole pig in the alley. That might be my buddy on the pole down the street.
Once this is complete, then return to the house. Once again assure the main breaker is off. (functionally the same as pulling the meter) Then,
and only then, close the breaker to the shop. This allows a backfeed to the main panel.
My wiring is marginal for 100 Amp service. But all breakers in this circuit are rated at 75 Amp, 2 pole. We don't use air conditioning. The furnace is gas, with a millivolt valve. As in, no connection to the electrical system. All other electrical loads have been run together and there was no interruption. The only combination that I haven't tried is the kitchen range, along with the dryer, and trying the welder. That combination is unlikely to occur.
The wiring is mostly copper, #2 AWG SER, with one aerial span of #2 Aluminium "tri-plex". Everything is set up as I would have connected an addition on an industrial building. The one difference is that instead of using crimp on barrels (cigars), I used kearneys (split bolts), which I prefer. Experience there. The Al to Cu connections were well greased with the appropriate grease.
Again, I admit to being heavy handed. But this system has been in place for over twenty (20) years. There have
never been any overloads, or complaints from the local power company. As far as recommending for your system, I won't. Not without walking over it and seeing it in person. But good judgement and willing to pay a few dollars more for the correct parts will yeild a solid system
Bill Hudson