On Sunday, September 10, 2017 at 4:10:35 PM UTC-4, wrote:
Yeah definitely want to ground the generator frame no matter what. I was thinking I could ground the frame through a household ground wire. In a strange way, if I use a standard 2-Pole transfer switch, just by connecting the generator 220 plug to the transfer switch I have connected the generator frame and my generator neutral & ground to my household ground distribution. Assuming I modify nothing at all, that's what would happen.

See my other reply I just made to my own post. I agree, you're on the
right track. What you stated above is all good and code compliant,
as long as *the neutral is not connected to ground at the generator*.
Doing some googling, it looks like some generators they are, some are not,
some have a jumper.





So in your example the hot wire comes loose in the generator hits the frame and is shorted to the ground connection in my house. Similar to what happens when a hot wire comes loose in a lamp with a grounded metal frame plugged into a wall outlet.

Agree.



I'm struggling to see why that doesn't work but I'm probably under-thinking this. The only thing I've been noodling is ground(s) potential differences. So the ground I'm standing on beside the generator (generator is on plastic wheels), could be at a different potential from the ground wherever my house transformer is grounded. But I'd expect that problem to be minor otherwise you'd have this issue on outdoor lights and outlets.

Just trying to understand it all a little more.

See my discussion about the issue of whether the neutral is connected
to ground at the generator in the other post. If it's not, then what
you're describing is fine, code compliant. But if the generator has
the neutral connected to ground, you then have 3 paths for neutral
current to flow between the house and generator:

1 - neutral wire in the cord, which you want

2 - ground wire in the cord, which is bad and a code violation

3 - through the earth ground at the house, through earth, back to generator

That is the issue, whether the neutral is connected at the generator or
not. If it is, then you have to treat it as a separately derived
system and switch the neutral at the transfer switch, which complicates
things. And then the generator is the place where the system neutral
and earth ground are tied together and you need an appropriate earthing
system that meets code, not a 2 ft ground rod that some Chinese generator
manual talks about. Which is why I'd avoid that choice.




Regardless, after more thought, I'm just going to install it all the right way. I'll ground the generator frame locally at the generator and install a neutral-switch type transfer switch. Generac sells a neutral switch kit for their transfer switches and reliance controls has the X-Series models which are designed for this very problem.

I'm just thinking through it all. Right now I just have a generator

Either way is right, the issue is whether that neutral is grounded at
the generator or not. I'd much prefer the first method, using the
house earthing system. It's likely a good earthing system, why
install another one and one that you have to remember to connect
the generator to? It's more than just using the typical one cord,
something someone else could easily overlook, forget, etc.

And if you have a panel that you can get an Interlockit kit for,
you can do it for the cost of that, a breaker, and an inlet.
I'd bet that's a lot less than a transfer switch.

Hope that helps.