mbrooke
Batteries Included
- Location
- United States
- Occupation
- Technician
Sounds about right?
This is an area that even confuses experts:
A switch would theoretically work, (and would probably be best) however, it may void the warrantee or the listing of the generator since its a non factory add on. Also, the NEC would probably not allow it either in that you are not allowed to switch a bond.
Per code if the generator is attached to a home's wiring, either the bond in the generator or home panel must be removed. Since it would be impractical to remove the bond from the panel as outages are temporary, that leaves us with the generator. Removing the bond in the generator allows us to meet the requirements of separately derived. This is the right way to do it when powering a home per NEC.
However when the same generator is used as a stand alone device, the bond would be missing. But here is the interesting part that others would know more than myself: Code from my understanding doesn't explicitly require a generator have a solidly grounded neutral system. Yet... NEC articles require that a 120/240 volt system be solidly grounded.
So with that said you are left with several options.
1. Either remove the bond and only use the generator for you home meeting code.
2. Remove the bond and use the generator for your home and stand alone applications. However your stand alone applications will probably be unsafe. GFCIs would certainly help, but I think code would still be violated.
3. Keep the bond and only use the generator for stand alone applications meeting code.
4. Keep the bond and run the generator for both home and stand alone use but you will be violating the NEC*.
5. Install a switch. It would meet all NEC requirements when used correctly (other than the whole can't switch a bond).
However, is the switch always going to be used right? If the generator is sold... "whats a neutral bond doohickey?
"
These are the 5 options. Ironically all of which fulfil one requirement at the expense of violating another. Trust me when I say even experts are scratching their heads.
* Personally I would pick option #4. Out of all the hazards this one would be the least concern. Why so? Stand alone applications would always be to OSHA, UL, NEC ect ect.... not issue here. In a home hook up you would be violating the separately derived NEC requirements. But, from a real world perspective I have never heard of this being hazard:
Current from the home panel would split between the neutral and ground wires. This would be a major issue in a home's hard wired infrastructure, yet IMO a lesser issue with a generator. The generator is on wheels isolated from earth, most generator hook ups happen to the main panel anyways, this is temporary and the objectionable current is only between the panel and generator. Would a small difference in potential exist between the generator and homes grounding system? Yes. But not by anything significant. I have never seen a home generator with bond in both places harm someone because of that.
A long reply, someone will probably explain it better than I can. If anything is confusing let me know.
This unfortunately isn't a clear in stone topic.
This is an area that even confuses experts:
A switch would theoretically work, (and would probably be best) however, it may void the warrantee or the listing of the generator since its a non factory add on. Also, the NEC would probably not allow it either in that you are not allowed to switch a bond.
Per code if the generator is attached to a home's wiring, either the bond in the generator or home panel must be removed. Since it would be impractical to remove the bond from the panel as outages are temporary, that leaves us with the generator. Removing the bond in the generator allows us to meet the requirements of separately derived. This is the right way to do it when powering a home per NEC.
However when the same generator is used as a stand alone device, the bond would be missing. But here is the interesting part that others would know more than myself: Code from my understanding doesn't explicitly require a generator have a solidly grounded neutral system. Yet... NEC articles require that a 120/240 volt system be solidly grounded.
So with that said you are left with several options.
1. Either remove the bond and only use the generator for you home meeting code.
2. Remove the bond and use the generator for your home and stand alone applications. However your stand alone applications will probably be unsafe. GFCIs would certainly help, but I think code would still be violated.
3. Keep the bond and only use the generator for stand alone applications meeting code.
4. Keep the bond and run the generator for both home and stand alone use but you will be violating the NEC*.
5. Install a switch. It would meet all NEC requirements when used correctly (other than the whole can't switch a bond).
These are the 5 options. Ironically all of which fulfil one requirement at the expense of violating another. Trust me when I say even experts are scratching their heads.
* Personally I would pick option #4. Out of all the hazards this one would be the least concern. Why so? Stand alone applications would always be to OSHA, UL, NEC ect ect.... not issue here. In a home hook up you would be violating the separately derived NEC requirements. But, from a real world perspective I have never heard of this being hazard:
Current from the home panel would split between the neutral and ground wires. This would be a major issue in a home's hard wired infrastructure, yet IMO a lesser issue with a generator. The generator is on wheels isolated from earth, most generator hook ups happen to the main panel anyways, this is temporary and the objectionable current is only between the panel and generator. Would a small difference in potential exist between the generator and homes grounding system? Yes. But not by anything significant. I have never seen a home generator with bond in both places harm someone because of that.
A long reply, someone will probably explain it better than I can. If anything is confusing let me know.
but not common in my area