# Trouble with generator backfeeding through subpanel



## siunmu (Aug 30, 2020)

I tried to backfeed my generator with a 10/4 twist lock cord through a 100 amp pool subpanel with a 30 amp 2 pole breaker.After flipping off all breakers in the main panel including the main breaker, and the pool pump breaker in the sub I flipped on the generator breaker in the subpanel and the breaker that feeds the subpanel in the main panel and the breakers tripped. The generator would also boggle down and shake. After some research I unbounded the neutral ground inside the generator and tried again, still no good.
I then connected the generator to the main panel and everything went fine,powers everything in the house.
So what's with the subpanel? If I would have bypassed the breaker in the sub and gone straight to the 2 power strips i think it would have worked.


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## ToolLover (Jan 13, 2020)

Your generator may have a ground tied to the neutral, hence a GFI fault and breaker trip.


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## siunmu (Aug 30, 2020)

ToolLover said:


> Your generator may have a ground tied to the neutral, hence a GFI fault and breaker trip.


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## iowagold (Jan 22, 2020)

siunmu said:


> I tried to backfeed my generator with a 10/4 twist lock cord through a 100 amp pool subpanel with a 30 amp 2 pole breaker.After flipping off all breakers in the main panel including the main breaker, and the pool pump breaker in the sub I flipped on the generator breaker in the subpanel and the breaker that feeds the subpanel in the main panel and the breakers tripped. The generator would also boggle down and shake. After some research I unbounded the neutral ground inside the generator and tried again, still no good.
> I then connected the generator to the main panel and everything went fine,powers everything in the house.
> So what's with the subpanel? If I would have bypassed the breaker in the sub and gone straight to the 2 power strips i think it would have worked.


danger danger on any back feed with out a proper interlock!!

at least do a lock out tag out on the main breaker!!
but only for an emergency!

next,
snap and post a few pix for us.
this will help us to see what is there.

a few questions for you
on the main panel feeding the pool sub panel
what is the exact breaker and numbers off that breaker.
and on the sub panel snap a few pix of the breakers in that panel as well.

as tool lover posted it could be an issue with gfci breakers some where.

this is exactly why i think all gen systems need volt and amp meters on the gens or at the generator input so you can see the load.

hey an idea if you trip out all of the breakers on both panels does it still do it?
if not then trip in the inlet from the generator only and see if it is ok then.


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## siunmu (Aug 30, 2020)

But why would it power the house through the same breaker in the main panel and not the subpanel. Too many grounded neutrals ? Parallel current back to the generator?


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## iowagold (Jan 22, 2020)

are there gfci units on the down stream?


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## siunmu (Aug 30, 2020)

siunmu said:


> But why would it power the house through the same breaker in the main panel and not the subpanel. Too many grounded neutrals ? Parallel current back to the generator?





iowagold said:


> danger danger on any back feed with out a proper interlock!!
> 
> at least do a lock out tag out on the main breaker!!
> but only for an emergency!
> ...


Trying to figure out how to post photos


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## siunmu (Aug 30, 2020)

siunmu said:


> Trying to figure out how to post photos


Red breaker is main, yellow is generator


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## iowagold (Jan 22, 2020)

on the sub panel is that a gfci in the lower right?
if so that is part your issue

the next is there is way to small of guage of wire on the lower white pool panel to be back feeding from.

run a proper inter lock on the panel with the main breaker on the main panel.

be safe!


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## siunmu (Aug 30, 2020)

iowagold said:


> on the sub panel is that a gfci in the lower right?
> if so that is part your issue
> 
> the next is there is way to small of guage of wire on the lower white pool panel to be back feeding from.
> ...


The gfci is dead and I flip off the breaker anyway but the power to it comes from conduit that goes under ground and I don't know where it goes. Would the neutral from the gfci I still play a role in this ?


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## siunmu (Aug 30, 2020)

siunmu said:


> The gfci is dead and I flip off the breaker anyway but the power to it comes from conduit that goes under ground and I don't know where it goes. Would the neutral from the gfci I still play a role in this ?


For the wire size I was using 10 gauge to a 30 amp breaker to panel which has 10 gauge going to the main


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## iowagold (Jan 22, 2020)

at how many feet?


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## iowagold (Jan 22, 2020)

oh i may need to clarify
point to where the gen is feeding power in


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## iowagold (Jan 22, 2020)

is the top photo the sub panel?


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