Pop goes the 50-amp GFI breaker!

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Old 05-31-20, 05:36 AM
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Pop goes the 50-amp GFI breaker!

Hi All,

I have a 4-wire coming out of my main Siemens panel in the house, feeding a CH subpanel in an outdoor detached workshop. The main-lug CH subpanel has separated neutral and ground buses, and is very well grounded from what i can see. The subpanel is a clean professional install, about 20 years old, 40 circuit load center so the box is mostly empty.

Now for some reason, there are like 14 circuits wired into this subpanel feeding about 14 receptacles/lights throughout! Maybe the guy had a couple 500ft 12-2 lying around at discount, who knows. Somebody i guess needed x2 tools running at two random locations throughout the workshop at the same time maybe.

Upgrading to GFI protection: the thing is outdoors, it gets wet, and i realize it is not up to code. I wanted to upgrade the panel by adding a 50-AMP BR (CH) GFI breaker so that i don't have to buy a dozen GFI outlets to add the needed protection. But also, some circuits really should be GFI protected more than others and i can't do that easily (e.g., the outdoor lighting runs). Also, i don't care about nuisance trips, it is a large mostly outdoor workshop and no big deal if the subpanel trips.

So, i added in the 50AMP GFI breaker (about a $120 part), put the pig tail into the neutral, and put the two hots accordingly, neutral went to the right lug (had a white spot). Ground stayed on the ground bar. ODDLY ENOUGH: the manufacturer (Eaton) stated that connecting the neutral was "optional" for 240V 2-poles GFCI breakers. I'm at a loss on that one. Whose option is it, and what factors go into making the choice?!? Is that the case when it feeds the whole subpanel? What would i do with the neutral, presumably just keep it on the lug on the neutral bar and then it is with the pig tail?

Flipped it on, all is well, everything working. Hit the test button. Spark/pop, and a little puff of smoke headed up from the top line screw from the GFI breaker. The hot lead next to the neutral on the GFI breaker had a little char ring around it when i took it back out.

So, the GFI is shot, but the breaker still works like a normal breaker.

You may ask why i didn't put the GFI at the main panel to feed the subpanel. Too far away if it trips, and my main panel is a **** show of fullness and hard to work in. (i have it on my list to have professionals replace it).

You may also ask why i haven't called a professional. That didn't go well. He didn't answer my questions and wanted to sell me 14 GFI/AFI combo breakers and charge $2000 for the swaps. According to him, the only way to do it 'right'.

THANKS FOR YOUR HELP/ADVICE!!!

 
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  #2  
Old 05-31-20, 06:00 AM
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A straight 240 volt load does not need or use a neutral. Things like your water heater and air conditioner. A 120/240 load needs a neutral. This is where the neutral is not optional.
 
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Old 05-31-20, 06:02 AM
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the manufacturer (Eaton) stated that connecting the neutral was "optional" for 240V 2-poles GFCI breakers. I'm at a loss on that one. Whose option is it, and what factors go into making the choice?!? Is that the case when it feeds the whole subpanel? What would i do with the neutral, presumably just keep it on the lug on the neutral bar and then it is with the pig tail?
The neutral is "optional" when you don't have a neutral wire on a 240 volt-only circuit. If there is a neutral you must connect it or the breaker will trip with the imbalance.

So what you did is back feed a GFCI breaker in the subpanel?
 
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Old 05-31-20, 06:02 AM
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Spark around a connection tells me the connection was not tight.

Neutral is only needed if you have 120 volt loads. If the breaker is used on a heater for example that is straight 240 volt, you don't need the neutral.
 
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Old 05-31-20, 06:04 AM
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Neutral is only needed if you have 120 volt loads. If the breaker is used on a heater for example that is straight 240 volt, you don't need the neutral.
Gotcha thanks! I have 120/240, so i would need it then..
 

Last edited by phattspatt; 05-31-20 at 06:25 AM.
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Old 05-31-20, 06:05 AM
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What I would do is get a refund on the 50 A gfci breaker and replace it with standard or maybe a 30 mA version
then consolidate these 14 circuits to maybe 4 to 6, splicing in the panel. Install 20A point of use GFCI recepts at a number of spots.
 
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Old 05-31-20, 06:07 AM
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So what you did is back feed a GFCI breaker in the subpanel?
Correct. Backfed a GFCI breaker into the subpanel. I hunted around, and i couldn't see a reason why that would not be allowed. The one GFCI breaker to backfeed the whole panel is the same price as just one of the 20-AMP 240V GFCI breakers.
 

Last edited by phattspatt; 05-31-20 at 06:25 AM.
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Old 05-31-20, 06:12 AM
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What I would do is get a refund on the 50 A gfci breaker and replace it with standard or maybe a 30 mA version
then consolidate these 14 circuits to maybe 4 to 6, splicing in the panel. Install 20A point of use GFCI recepts at a number of spots.
I'm with you, and i can do that. However, the 20-AMP 240V GFCI breaker ALONE that i would need for the circuit driving the pool pump, is the same price as the 50 for the whole panel.

The recepts are also in really good shape.
 
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Old 05-31-20, 06:20 AM
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Spark around a connection tells me the connection was not tight.
OK so you may have got me. The 4-wire coming into the subpanel is thick AWG-2 THWN-2 and i had to nip away at the copper strands to get a fit into the 50-AMP hole. From my calculation on length, that cable should easily support 100-AMP or more.

I read online about using "pins" to reduce the gauge coming in, but i didn't know how to do that.

I wasn't happy with how the twisted copper sat in the breaker..

Could that have killed the GFCI on tripping it?!?
 
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Old 05-31-20, 06:29 AM
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Backfed a GFCI breaker into the subpanel. I hunted around, and i couldn't see a reason why that would not be allowed.
Back feeding a GFCI breaker would be the same as wiring a GFCI receptacle backward. If you connect the LINE to the LOAD terminals the device will not function correctly. I suspect you cannot do this with a GFCI breaker.

I would recommend installing a small panel before the sub panel and install a new GFCI breaker there. Then connect the load terminals to the main lug panel.

replace it with standard or maybe a 30 mA version
A 30mA GFCI device does not provide protection for personnel, only equipment.
 
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Old 05-31-20, 06:49 AM
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If you connect the LINE to the LOAD terminals the device will not function correctly. I suspect you cannot do this with a GFCI breaker.

I would recommend installing a small panel before the sub panel and install a new GFCI breaker there. Then connect the load terminals to the main lug panel.
awesome advice!! Now it makes sense. some reason my brain wasn't thinking in terms of LINE and LOAD like on a receptacle..

Also, with a little panel feeder, it gives a very convenient 'disconnect'.

Grounding question: What do i need to do with the little 'feeder' panel, just ground the small panel with 8AWG with the ground bar on the bigger sub-panel? If i have to shoot new grounding rods and run more #6 grounding wire just for the little panel, i probably won't go this option.
 
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Old 05-31-20, 07:00 AM
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You need to move any ground rod connections to the new mini panel and feed the existing panel with a four wire feed.
 
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Old 05-31-20, 07:01 AM
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You need to move any ground rod connections to the new mini panel and feed the existing panel with a four wire feed.
makes sense, thanks all!!
 
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Old 05-31-20, 10:58 AM
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Would anyone be able to give insight why hitting the test button would fry the GFCI breaker other than a preexisting defect in the breaker unit?

If there was a significant load (more than 30 amps) it would be normal for an arc to occur at the breaker contacts when they open whether due to flipping the handle or a current overload, or a ground fault including pressing the test button.

Hitting the test button does not load the breaker down to its full 50 amps, only causes an additional few milliamps to flow, not enoughg to char something.
 
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Old 05-31-20, 01:16 PM
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The OP never said how they tested the GFCI function to know that is was fried. I suspect the arc/flash was from some other cause.
 
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Old 06-01-20, 11:02 AM
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i added in the 50 AMP GFI breaker (about a $120 part),
That's way too much when you can get the same breaker and the enclosure for much less(About $85).

https://www.homedepot.com/p/Eaton-BR...PAST/206696172

Under the circumstances the breaker might be warranted by a distributor, but you'd still have to buy an enclosure for it. That relatively little project is getting pretty expensive.
 
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