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Discussion Starter · #1 ·
I bought a 3500W generator to keep a freezer and a few small appliances running in a power outage. I bought a Sportsman (Dual Fuel) from Home Depot (link below).

What grounding is required in MN and for safety anywhere? My belief and testing shows this is a "floating neutral" generator where the neutral is not bonded to the ground or frame (testing showed ground is bonded to the frame).

If I need to use the generator, I envision using this in the event of a power outage at my house. I'm not planning to use a transfer switch (or backfeed...) at the house and instead would just unplug the appliances from the house and plug them into the generator.

My first read of the codes and OSHA and other sources is that I don't need to provide an earth ground.

That said, it seems if I could ground to earth it would be better? I could run a wire to the house ground rod and connect to that. Would that give some (needed) protection? Would this potentially cause other issues to use the same ground?

Anything else to consider that I'm missing here? I imagine that people use these all the time at campsites or jobsites and just plug devices in without driving an 8' rod 4' into the ground, but can / should I do better and safer?

Thanks in advance. I tried to research this and started to get more confused.

Here's the link to the product:
https://www.homedepot.com/p/Sportsm...s-on-LPG-or-Regular-Gasoline-803266/304541553
 

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Yes, it needs to be grounded. See page 13 in the manual.
Here's what that page says:

Ground this generator by tightening the grounding nut against a grounding wire as illustrated in Figure 3. A No. 12 AWG (American Wire Gauge)

stranded copper wire is generally an acceptable grounding wire. The other end of this grounding wire should be connected to a copper or brass

grounding rod that is driven into the earth.


Grounding codes can vary by location. Contact a local electrician for information on grounding regulations for your area.
Although probably not 100% code compliant, I have used welder ground clamps for portable generator grounding. Easy to connect to a ground rod, waterpipe, EMT conduit, etc... but also where i am, I'm not required to ground a portable generator....

OP, someone who knows local codes will have to comment. Where are you located?
 

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Discussion Starter · #4 ·
Here's what that page says:



Although probably not 100% code compliant, I have used welder ground clamps for portable generator grounding. Easy to connect to a ground rod, waterpipe, EMT conduit, etc... but also where i am, I'm not required to ground a portable generator....

OP, someone who knows local codes will have to comment. Where are you located?

Minnesota. But I want to be safe not just code compliant.


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Discussion Starter · #5 ·

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I'm wondering why you need to ground it since you're not connecting it to the house wiring. You're just running a cord to some appliances, right?
 
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In your situation, connecting to the house ground would be taking on danger rather than preventing it. If a primary line fell across the service drop to your house (or a lightning stroke hits it), it could electrify the neutral/ground conductors and back feed out to your generator. Not all of that kind of energy goes to the funky ground system of a house. If you were near it or fueling it at the time, you'd be wishing you hadn't run that wire to the house ground. As for providing a ground rod at the generator, I suppose that might have some small value but I haven't seen it done on the many jobs sites we ran from generators. Sounds silly to me... akin to that screen door on a sub or the basement for a motor home. :smile:
 

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As a practical matter, it does not need to be grounded unless you are connecting it to the home's electrical system or installing the generator permanently. Grounding will not serve any actual useful function if the generator has a floating neutral and you are just plugging appliances into it with cords. Grounding has no purpose in this application.
 

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Discussion Starter · #10 ·
In your situation, connecting to the house ground would be taking on danger rather than preventing it. If a primary line fell across the service drop to your house (or a lightning stroke hit it), it could electrify the neutral/ground conductors and back feed out to your generator. If you were near it or fueling it at the time, you'd be wishing you hadn't run that wire to the house ground. As for providing a ground rod at the generator, I suppose that might have some small value but I haven't seen it done on the many jobs sites we ran from generators. Sounds silly to me... akin to that screen door on a sub or the basement for a motor home. :smile:

Thanks for your replies.
I’ve never used a generator before. I’m relatively savvy on electrical stuff and have done many electrical projects at my home and had them inspected (and passed with a “nice job” comment so to speak). What extra risk am I taking in this case with a generator that’s a floating neutral and not connected to ground vs just using a house outlet? Assume I won’t stand in a puddle...


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Discussion Starter · #11 ·
...Grounding will not serve any actual useful function if the generator has a floating neutral and you are just plugging appliances into it with cords. Grounding has no purpose in this application.

Thanks for your reply. Can you please elaborate on why? For the part I quoted. Thanks.


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Zero extra risk. In fact, the floating ground means that you can touch either of the line leads and be standing in a puddle and not get shocked. It's actually safer than grounding one of them. Just don't touch both of them at the same time!
 

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Discussion Starter · #16 ·
A cord and plug connected generator should not have a floating neutral.
Thanks for the reply. So maybe my real question is - should I bond the ground and neutral when using with extension cords? It seems the answer is yes but it would be nice to get confirmation.

I noticed that my GFCI "extension cord" will not trip when connected to the generator but I believe it will trip if I bond the neutral and ground... It looks like there are plug-in devices sold for this purpose (and of course it's easy enough to DIY).

Any insight would be appreciated. Thanks.
 

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With a floating neutral generator, as mentioned preceding if you touched the hot wire and ground at the same time, no current is expected to flow through you. Current seeks to return to where it came, namely from the generator hot back to the generator neutral. and you do not see a path back to the generator via ground. With no imbalance between the current out the hot and current back via the neutral the GFCI will not trip.

Meanwhile don't eliminate the GFCI just because the generator neutral is floating. You are not absolutely positively sure there is no path from ground to neutral, perhaps a path with a high enough impedance to not count as a ground -neutal bond but allowing enough current or phantom current to electrocute you.
 

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Discussion Starter · #20 ·
With a floating neutral generator, as mentioned preceding if you touched the hot wire and ground at the same time, no current is expected to flow through you. Current seeks to return to where it came, namely from the generator hot back to the generator neutral. and you do not see a path back to the generator via ground. With no imbalance between the current out the hot and current back via the neutral the GFCI will not trip.

Meanwhile don't eliminate the GFCI just because the generator neutral is floating. You are not absolutely positively sure there is no path from ground to neutral, perhaps a path with a high enough impedance to not count as a ground -neutal bond but allowing enough current or phantom current to electrocute you.

I think I understand. My concern is that if an extension cord gets a short between hot and ground, the generator frame will be energized and it will not trip the generator breaker.


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