Does 590.6(A)(3) basically put a end to portable generator installations?

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frankft2000

frankft2000

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Its sure looks like it to me, unless you use a 50 amp setup. I do not see how you could use a 20 or 30 amp generator inlet box with a generator made after 1-1-2011. Am I missing something?
 
Wouldn't it depend on whether the grounding conductor is bonded to the generator neutral? As long as the generator neutral floats, I would think it would be OK with solid neutral switches. The house neutral-ground bond isn't causing any grief if the generator neutral is floated.
 
suemarkp said:
Wouldn't it depend on whether the grounding conductor is bonded to the generator neutral? As long as the generator neutral floats, I would think it would be OK with solid neutral switches. The house neutral-ground bond isn't causing any grief if the generator neutral is floated.
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I don't think so. The generator has a GFCI. A home electrical system has the ground and grounding conductors bonded together. A gfci will trip if the two are together.
 
frankft2000 said:
I don't think so. The generator has a GFCI. A home electrical system has the ground and grounding conductors bonded together. A gfci will trip if the two are together.
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Only if there is a return path, back to the generator's grounding point, that is not through the GFCI.

As suemarkp said, if the generator is 'floating' there is no complete circuit during normal operation.
 
frankft2000 said:
I don't think so. The generator has a GFCI. A home electrical system has the ground and grounding conductors bonded together. A gfci will trip if the two are together.
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The only way for it to work would be to use a 3 pole transfer switch and transfer the neutral. but the neutral to ground bond will have to remain at the generator.

Multiwire circuits should not be a problem since the generator has a two pole GFCI for the 120/240 volt receptacle.
 
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hurk27 said:
The only way for it to work would be to use a 3 pole transfer switch and transfer the neutral. but the neutral to ground bond will have to remain at the generator.
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That would also require the neutral bond of the house to be on the line side of the transfer switch, not in the panel, making the house panel a sub-panel, which would require a service-rated T/S or separate main disco.

If I'm not mistaken, that is.
 
I was thinking this too, then I realized that I have installed all of the loads that I wanted fed from the generator in a separate sub-panel. Since it is a sub-panel the neutrals and grounds are separated, so the GFCI on the generator should be fine (no neutral current on the grounding conductor). Looks like I did something right. If you are using a portable generator to power the entire main panel (grounds and neutrals tied together) it seems that the GFCI on the generator is going to trip.
 
LarryFine said:
That would also require the neutral bond of the house to be on the line side of the transfer switch, not in the panel, making the house panel a sub-panel, which would require a service-rated T/S or separate main disco.

If I'm not mistaken, that is.
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Yea I didn't think of how others do portable generators, I always use a sub panel for the generator when it portable, this way I can kind of control what the homeowner puts on the generator.
 
LarryFine said:
That would also require the neutral bond of the house to be on the line side of the transfer switch, not in the panel, making the house panel a sub-panel, which would require a service-rated T/S or separate main disco.

If I'm not mistaken, that is.
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In what case would you be able to install a transfer switch where the MBJ will still be in the panel served by the transfer switch?:confused:
 
jim dungar said:
Only if there is a return path, back to the generator's grounding point, that is not through the GFCI.

As suemarkp said, if the generator is 'floating' there is no complete circuit during normal operation.
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If the neutral is floating at the generator it will render the GFCI ineffective this is because all current will return through the neutral from the neutral to ground bond after the GFCI, any ground fault will place current on the neutral and the GFCI will treat this as normal current.
 
My 15KW portable generator has a floating neutral. It only has GFCI's on the 120V receptacles. Not sure how much help a GFCI will be on a floating system, but OSHA requires them. OSHA may also require non-floating neutral generators in the over 5KW size. If so, you'd want a generator that could easily unbond its neutral if you want to power a house with it (and assuming it is a non-worker type situation so OSHA doesn't apply).

I also wonder how floating a floating neutral generator is. There will be some capacitive coupling to earth and up the wheels/frame in the floating system. So there is a second return path via " ground" to the generator. But I would think that would be a rather high impedance path and things may still work just fine with a "main GFCI". I'm not sure what environmental or operating conditions would put more current on that capacitive pathway. Rain? Long cords?
 
as often, I'm lost

as often, I'm lost

The Op sounds to me as if he's talking about using a smaller portable generator to power some circuits in a house or something. there was some discussion of a gfci tripping.

I'm not understanding what the problem is. I wonder if someone would clue me in:confused:
 
Most home transfer switches use a 4-wire feed and a solid neutral transfer switch. If this feeder is GFCI protected, the main bonding jumper in the house will allow the current to split between the equipment grounding conductor and the neutral. However, the generator grounding conductor and neutral must be bonded in the generator in order to create the parallel circuit for neutral and ground. I believe a non-floating generator on the typical residential transfer switch would be a code violation, so in theory things should still work.

I'm not so sure generator size matters. The problem is akin to connecting the neutral and ground downstream on a GFCI receptacle. But with no equivalent of a main bonding jumper, you won't get a low impedance parallel path.
 
Mark, the problem is for a GFCI to function, the EGC must be bonded to the supply neutral ahead of the GFCI for it to reference current flow taking a different path back to source, if the neutral to ground bond is on the load side of the GFCI without a bond ahead of the GFCI then the GFCI will only reference the EGC as if it was the neutral and will not trip.

If you have a bond on both the line and load side of the GFCI of course it will trip.

The only way to make a 2011 generator work as a feed for a house will be to use a sub-panel with separated grounds and neutrals, and transfer the neutral, this will leave the neutral to ground bond intact in the generator, and not require much in modifying the service panel.
 
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Many portable generators do not bond the neutral. The GFCI will work if there is some type of current path that is other than the two conductors that feed the GFCI. In general that would take more than one fault. There is no easy way to tell what generators bond the neutral and what ones don't unless you look in the manual. Even with in the same brand they do it both ways.
 
don_resqcapt19 said:
Many portable generators do not bond the neutral. The GFCI will work if there is some type of current path that is other than the two conductors that feed the GFCI. In general that would take more than one fault. There is no easy way to tell what generators bond the neutral and what ones don't unless you look in the manual. Even with in the same brand they do it both ways.
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Continuity test between neutral and ground terminal of receptacle is easiest way to tell. I have not seen one manufactured in last 10 or 15 years that is bonded that I can recall. If they have a 120/240 volt receptacle it is always 4 wire receptacle. If it is older generator and has a 120/240 3 wire receptacle the frame is likely bonded to the neutral.
 
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