Back in the day I used to be responsible for wiring the Infantry bivouac areas. They would drop a 35kw genny and we ran all the cabling etc. Back then there was some weird things with a voltage that used to surprise the heck out of us.
One day got a trouble call the colour TV in the mess that wasn't working right. Stopped in and found that one the color jets on the picture tube was out. Further investigation found that there was almost a 6v 'floating' voltage to ground. Enough to screw up the TV ..mind you that was back in 1981.
The problem turned out to be the engineers that dropped the genny never established a good ground stake ( sandy soil).
The lesson: always drive in a ground stake and ground your generator frame. Especially with house wiring that has a neutral /ground connection. If you look at the stator windings in a generator you'll see the neutral line bolted to a ground lug.