said by TheTechGuru:That's where we part ways. Connecting the generator's neutral and ground to the panel's common rail is fine, but tying the generator's hots to the panel's hot rails and turning off the main is NOT what I'd do. said by garys_2k:
No, connecting the generator's ground terminal to the house's ground system will NOT change the generator's neutral-ground bond type. Definitely DO connect the generator's ground to the house's ground, but using the cord will "fix" that bond issue.
Connecting BOTH the common AND ground from the generator to the common/ground rail in the main circuit panel of the house will fix the problem and while one is in there might as well connect the hot(s) from the generator to the appropriate rails in there. Just turn off the main so you don't back feed.
Some panels have more than one "main" (six lever rule), no wires should connect directly to the rails (should go through a breaker) and a physical method of preventing both the main(s) and the generator's feed breaker from both connecting to the hot rails at the same time should be used, even for temporary or emergency use.
Since the more recent questions are regarding this one use (hot water heater that needs its power source to have N-G bond) then I'd leave the panel closed and do my wiring at the heater PLUS the ground line from the generator's ground terminal to the electrical system's ground.