Ground fault protecting circuits fed by 220V portable Generator

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Jons

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Receptacle on 220V output of portable generator only has connection via plug of 2 hots and a ground. Can this be successfully fed into panel with a 2 pole GFI breaker, considering there is no neutral wire? Output of 2 pole GFI breaker to supply power to 220V marine equipment only. Would the neutral pigtail off the GFI breaker be terminated in the panels common bus bar (assuming the green grounding screw is installed), or does the neutral and gnd bars have to be isolated as a subpanel would be wired with the GFI breaker's pigtail winding up isolated from the gnd bar in the panel...which would be basically be tying the pigtail to the air since the generator feed would only be the two hots and the ground wire. Please advise.
 

Jons

Member
Generator feeding 2 pole GFI breaker in panel

Generator feeding 2 pole GFI breaker in panel

...which would be basically be tying the pigtail to the air since the generator feed would only be the two hots and the ground wire. Please advise.

Obviously not this scenario
 

Craigv

Senior Member
Typically most GFCI's need the neutral on the line side to power the electronics, but do not require a load-side connection to operate. YMMV and you should check the manufacturer's instructions for the GFCI.
 

Adamjamma

Senior Member
Now, unsure of this but: Isnt this basically what the main panel does, when you are grounding the Neutral from the Services Supplier to the ground bar? Connecting the Neutral from the breaker on load side to grounding bar should do what is needed done, shouldnt it?
 

Craigv

Senior Member
Now, unsure of this but: Isnt this basically what the main panel does, when you are grounding the Neutral from the Services Supplier to the ground bar? Connecting the Neutral from the breaker on load side to grounding bar should do what is needed done, shouldnt it?

We don't really have much info from the OP here, so I only addressed the GFCI. Even that is iffy, because we don't know the specific GFCI he's using. Most 2-pole GFCI's require the line-side neutral in order to function, regardless of a load-side neutral being connected. If the OP's generator has no neutral (is 240v only) then he's out of luck unless he can source a 2-pole GFCI that doesn't need a neutral.
 

FionaZuppa

Senior Member
Location
AZ
Occupation
Part Time Electrician (semi retired, old) - EE retired.
a 220v only gen? perhaps just get a new gen that is 120/240 and has gfi on it already?

or can you place a 240/240ct xfrmer between gen and gfi unit?
 

jaggedben

Senior Member
Location
Northern California
Occupation
Solar and Energy Storage Installer
Seems to me it would probably function as long as the generator supplied ground is 120V to the hots. I think it's a code violation though.
 

FionaZuppa

Senior Member
Location
AZ
Occupation
Part Time Electrician (semi retired, old) - EE retired.
Seems to me it would probably function as long as the generator supplied ground is 120V to the hots. I think it's a code violation though.

why would a gnd be needed, gfi will still work w/o a gnd.
if the gen has 3wire 240v only receptacle, then is that 3rd wire just a bond wire or an actual EGC? I suspect it is an EGC, thus should be 120v to either hot leg. Or perhaps its a 2wire 240v gen? that would be odd, no? If its a 2wire 240v gen then no matter how it's used it's code violation due to no EGC?

but if it really needs to be wonky rigged on a 2wire 240v and gfi must be there, two 5w 10k resistors in series across the 240 legs and use the CT point as the 120v "N" to the gfi so it can run the internals.

code violation? probably yes. but perhaps just easier to get a new gen for the task at hand, 120/240 w/ built-in gfi. done.
 
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jaggedben

Senior Member
Location
Northern California
Occupation
Solar and Energy Storage Installer
why would a gnd be needed, gfi will still work w/o a gnd.

I don't know much about, say, UL requirements for GFI breakers. But it seems to me that it shouldn't turn on if there's no reference to its neutral terminal. And it certainly wouldn't operate on a ground fault current if it has no reference to ground.
 

FionaZuppa

Senior Member
Location
AZ
Occupation
Part Time Electrician (semi retired, old) - EE retired.
I don't know much about, say, UL requirements for GFI breakers. But it seems to me that it shouldn't turn on if there's no reference to its neutral terminal. And it certainly wouldn't operate on a ground fault current if it has no reference to ground.

use two resistors like i mentioned to get 120v to the gfi so it can at least run the guts to get gfi protection. that is certainly way better than no gfi.

gfi doesnt need EGC to protect the downstream device.
 

Jons

Member
Titan Generator schematic

Titan Generator schematic

Here is the schematic for the generator feeding the GFI I spoke about in my original post
 

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Jons

Member
GFI fed by non-GFI Generator

GFI fed by non-GFI Generator

Here's another question...Is the fact the 2 Pole GFI breaker trips when the test button is pressed when breaker is powered and neutral and ground are connected in panel, indicative of the GFI being internally powered and functional? The breaker trips when the test button is pressed so this leads me to believe it is internally powered.
 

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JPinVA

Senior Member
Location
Virginia
If memory serves me, I believe code requires a neutral be delivered to the first disconnect regardless of whether it's needed downstream.

I believe the fundamental safety issue is the ability to clear a fault "properly". If one of the hots connects with the equipment chassis, the chassis energizes to 120V wrt ground. Current will flow along the EGC back to the panel. If there isn't a neutral at the panel, how does the current get back to the generator to facilitate an OCPD trigger?
 

jaggedben

Senior Member
Location
Northern California
Occupation
Solar and Energy Storage Installer
If memory serves me, I believe code requires a neutral be delivered to the first disconnect regardless of whether it's needed downstream.I believe the fundamental safety issue is the ability to clear a fault "properly". If one of the hots connects with the equipment chassis, the chassis energizes to 120V wrt ground. Current will flow along the EGC back to the panel. If there isn't a neutral at the panel, how does the current get back to the generator to facilitate an OCPD trigger?
I think the problem here is that it hasn't been established that the generator has a neutral to bring. If we could read that schematic it would help.
 

FionaZuppa

Senior Member
Location
AZ
Occupation
Part Time Electrician (semi retired, old) - EE retired.
If memory serves me, I believe code requires a neutral be delivered to the first disconnect regardless of whether it's needed downstream.

I believe the fundamental safety issue is the ability to clear a fault "properly". If one of the hots connects with the equipment chassis, the chassis energizes to 120V wrt ground. Current will flow along the EGC back to the panel. If there isn't a neutral at the panel, how does the current get back to the generator to facilitate an OCPD trigger?

if the current is not between the two gen hots, the gfi should trip. load side needs no neutral.
the issue at hand was said that the gfi had no place on gen to connect gfi N pigtail so the internal can run.

if there is no CT from the gen then i dont see how any 1pole BC's in panel would work. from 1st post i just thought it was like a single 240v ocpd spa panel, for feeding one item using the gen, but wanted gfi protection.

i think best option is to buy a gen that has 4wire output, which would be required if this gen is being used to power a resi panel.

it's still kinda baffling to me why 2pole gfi ocpd's use N pigtail, you can save all that wire buy making a CT with two resistors across the hots. the only risk i see is if you lose a hot leg the gfi part goes dead, not so when using N pigtail, but its ocpd that is locked into the panel, so losing hot leg is likely a very rare event.
 

Craigv

Senior Member
I think the problem here is that it hasn't been established that the generator has a neutral to bring. If we could read that schematic it would help.
I think there's a neutral. Bear with me...

The picture is indeed very difficult to read. I can only guess at the wording.

But from what I can sortof see there appears to be a neutral, the yellow wire running from a common stator connection on the generator.

There appears to be at least one 120v receptacle, at far left. So this should be a 120/240v generator, not a 240v-only generator, and therefore has a neutral, most likely that yellow wire. I'd guess the third receptacle, at the right of the other two, would possibly be a locking 4-wire.
 

Craigv

Senior Member
Here's another question...Is the fact the 2 Pole GFI breaker trips when the test button is pressed when breaker is powered and neutral and ground are connected in panel, indicative of the GFI being internally powered and functional? The breaker trips when the test button is pressed so this leads me to believe it is internally powered.

It would be really helpful to provide us with the generator model #, the exact cordset being used and the type of receptacle (marked on its face) you connect it to, and the make and model of the GFCI being used.

-Are you certain the cordset is connected to the generator ground and not to its neutral? The gfci will function if the gfci's line-side neutral is connected. The schematic indicates this generator does not bond the neutral to ground. So if your cord only connects the 2 phases and the ground, there is no neutral to the gfci and it is unlikely to function.

-why are you only using a 3-wire cord? If you simply get a 4-wire cordset, there will be no question as to whether the setup can be word correctly and safely. The generator appears to be set up to use a 4-wire 120/240v cord as commonly used to power temporary power panels, RV's, and marine shore power.
 
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