1.
i think some of the generator already have that build in - right?
2.
just wondering - are you guys planning to bolt down the generator to the shed/bottom? so it is harder for someone trying to steal it...?
Typically they do not come with a surge protector. They do have an overload protector on the generator. However, I'm referring to something between your house's circuit breaker and the generator. When I had my 20K installed.. the electrician had installed that as well.. and it wasn't like he was taking me for a ride.. as that was not extra. This would protect you incase there is a big surge... from the generator caused by act of god, i.e. lighting.
I strongly recommend you bolt down any plastic shed, as well as, bolt the generator with U-bolts to the flooring of the shed. Speaking from my experience... I had one of those plastic/rubbermaid sheds filled with my lawn mower, whole bunch of shovels, pics, weed wacker, leaf blower and etc.. (roughly about 600 lbs) and one gust of wind flipped the shed on the side. They do sell shed anchoring kit at most hardware stores. It's worth the effort.