That does indeed describe a properly engineered 50 amp device.
It is normal for appliances to use slightly lighter gauge wire than would be used in building wiring. You can observe that inside electric ranges, dryers, and water heaters, where you will see the 10 or 8 gauge incoming supply wires to a terminal and then 12 or 14 gauge wire going from the terminal block off to the components.
Because the wire is inside an enclosed box, and is not tightly bundled or surrounded by thermal insulating materials, its elevated temperature will not cause any danger. It will run a little warm at peak current, but be far below "hot". The same is not acceptable inside dwelling walls were it will be in contact with wood, fiberglass, cellulose insulation, etc.
As for standards, I have determined this is beyond the scope of the NEC and falls into the domain of the National Fire Protection Association (NFPA) standards. That seems to cost $$ to view.
I will join longneck, you need to give to give this one to a pro.
If you do not understand about back-feeding a circuit, already, it is too easy to kill someone. I say this without exaggeration.
The biggest problem with running a generator with a transfer switch is that you have to wire it into your main panel.
For basic protection of life, (as well as the law,) it must NOT be possible to have your generator and the power to your house on the same wire, at the same time.
This is not a case of, just for a few seconds, or I would not do that, or I will triple check a written list.
It must not be possible under mechanically, electrically, on with quantum physics.
The reason is that if you put power on the 'dead' wires to your house, it is possible to kill someone a mile away, or more.
Emergency workers expect down lines to be dead. Yes, they do check first, but that does not mean that the situation can not change while they are working on them.
Transformers work backwards, low voltage at your generator (240) quickly becomes high voltage (thousands).
And sometimes people, and pets, or cars, just do not even see a fallen power line.
This is a case of some money to a pro vs life.
Best Answer
You have to run 4-wire to a generator. A separate neutral and ground wire is mandatory. A ground rod will not substitute. The only way to avoid running a 4th wire is to use non-flex metal conduit the whole way. (or run 120V only, but that's no fun).
But that's OK, I'm about to save you enough money to pay for the ground wire or the conduit. Minimum ground wire size is #8 copper or insulated #6 aluminum.
Since the generator run will be circuit breaker protected at 100A, you can use 100A rated wire. Voltage drop will not be a concern at only 80 feet.
That is #1 aluminum wire if a) the wire or cable insulation is a type permitted 75C operating temperature, and b) the terminations (lugs) are rated for 75C operations. The breaker panel lugs certainly are; whether Generac graces you with 75C lugs is a question for Generac. you would think...
Do not put cable in conduit if you can possibly avoid it. It's not illegal; just exceedingly difficult and serves no useful purpose.
If your entire run is in conduit, it behooves you to use THWN-2 or XHHW-2 wires which are indeed allowed 75C in practical use. (technically they could go 90C but that requires meeting a long list of conditions; the electrical inspector is likely to nix this). NM is not allowed outdoors and UF is allowed only 60C.
If your entire run is not in conduit, and making it so is impracticable, you can transition from one cable type to another in a reasonably large box using splices. The box must remain accessible without tools or dismantling any part of the house.