Making a generator cable. 

If I want a generator point attached to my grid tied house, I expect I have to get a transfer switch installed in the switchbox to isolate the grid and allow power from the "generator"? I've also been toying with the idea of connecting a electric HWS with the gas HWS so the electric HWS pre heats the water fro the gas. The energy for the preheated water will come from solar panels -> inverter - > electric HWS. (or maybe replace the element in the HWS with a suitable DC element)