While this will work in MAYBE a situation like firemedic, It's illegal a violation and DANGEROUS!
An Interlock kit (not the ones on flebay) from the manufacture of the panel it's going in to and a corresponding in feed receptacle is the correct , safe, legal way
to do it.
Picture this.
You go to work,store anywhere and the power comes back on.
Your wife,kid goes to the panel and throws the main on WHILE the gen is still hooked up!
I can tell you this for a fact.
Your next trip WILL be going to the hospital to see how bad it is!
An interlock kit will not let this happen. One of the 2 breakers HAS TO GO OFF.
Another thing that WILL happen out by me is if the utility hears a gen while they have to work on the lines by your house and they see it wired up like the way mentioned, the WILL cut your service off at your house!.
Please spend the $350 and do it the right way!
Not trying to be a prick...but I'm licensed electrician and KNOW what will happen IF someone does what I mentioned in the scenario above.