reply to Subaru
Re: Interlock Murray panel i'll second interlockkit.com. I do not work for them, i've installed three of their units. Two murrary (30a and 50a) and an ITE (30a).
As far as their fit: it was tight on all three. The most expensive was the 50a. Buying the kit, inlet and cord from them was around $440 shipped. The breaker and cable at home depot was another $60. $500 total. Their cord was good quality (4g SOOW). I would look for another inlet, though. While theirs was sufficient I did not like the size nor the way the inlet was held into the panel. Using 6GA wiring it was stiff to fit in place.
My issue with the transfer switches (separate panel) is that you then have to pick 6 (or however many) circuits which you want to power. Not sufficient for me. My kitchen lights, kitchen outlets, living room lights, fridge and furnace would fill all 6 slots. What about anything else I want to power? Extension cord from kitchen to my TV?
With the interlock kit I can power everything - generator being the limiting factor. All I do is flip off the stove and I can use my house as I need.
My friend who got the 50a interlock has a rental in the basement. Their bathroom/shower uses a sump pump. They have their own panel in the unit. Using a transfer switch he would have to run the sump pump back to the main panel. Using the interlock and a 9,000 watt generator he was able to power his house and apartment with no problems.
His power mast was taken down during sandy. Before they hooked him up they saw the generator and asked to look at the panel. The guy looked at the interlock, saw it was UL listed and said he was good to go.