Reverse power flow on GFCI breaker?

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Tedh777

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Hi,
A quick question about the technical feasibility of reversing power flow through a GFCI breaker. The situation is for an installation of a pool heater fed from a sub panel in an outbuilding on a 30A GFCI breaker. The heater is disconnected and stored for the winter. There is a small backup generator, 30A, being wired in to the same outbuilding that will only be available in the winter (stored in the summer). I am just curious more than anything if the now unused GFCI breaker could be used for the generator as the pool heater is disconnected for the winter. I know reverse power on GFCI outlets will not work but am not sure about the same thing for breakers. Will power even flow through a GFCI breaker in reverse or will it trip? What are your thoughts on the circuit design in a GFCI breaker in this situation?

Thanks,
Ted
 
GFCIs are marked load and sometimes line. That being the case it is a violation for those of us under the NEC to backfeed it.

I don't know if it would work or not but for the price of a two pole 30 amp plug in breaker I would not bother to find out.
 
Tedh777 said:
Hi,
A quick question about the technical feasibility of reversing power flow through a GFCI breaker. The situation is for an installation of a pool heater fed from a sub panel in an outbuilding on a 30A GFCI breaker. The heater is disconnected and stored for the winter. There is a small backup generator, 30A, being wired in to the same outbuilding that will only be available in the winter (stored in the summer). I am just curious more than anything if the now unused GFCI breaker could be used for the generator as the pool heater is disconnected for the winter. I know reverse power on GFCI outlets will not work but am not sure about the same thing for breakers. Will power even flow through a GFCI breaker in reverse or will it trip? What are your thoughts on the circuit design in a GFCI breaker in this situation?

Thanks,
Ted
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I see the wheels in your head spinning from here.

I just replaced a pool panel where someone wired a generator into it to back feed the house.

I would not suggest using those wires for the two applications unless you really sit down and figure out how to do it the right way, that's even if there is a right way.
 
ritelec said:
I see the wheels in your head spinning from here.

I just replaced a pool panel where someone wired a generator into it to back feed the house.

I would not suggest using those wires for the two applications unless you really sit down and figure out how to do it the right way, that's even if there is a right way.
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Spinning wildly!

I know what you mean about the two applications, but in this situation there would technically only be one application at any given time. And it is not that this is the actual going to occur, but it is the odd concept of reverse power on the GFCI breaker that made the wheels spin.
 
texie said:
Here is a Square D white paper on this subject: http://static.schneider-electric.us/docs/Circuit Protection/0900DB1001.pdf

I located this while researching a situation where PV was to be back fed into a 480 volt GFPE breaker.
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Thank you! That is the answer I was looking for. Will not work because of the circuitry. I figured that was probably the case but couldn't see any obvious reason for it to not work myself. Now I know and can pass that on to the others I asked that had the same confused thoughts as myself.
 
Yup, I've seen it with FPE Stab-Loc "Spa Buddy" kits. They use a reversed 2P50 GFCI that connects the Line to the screw terminals and the Load out the stabs. Of course some people try to install this breaker into a regular panel and it dies.
 
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I understand the curiosity of whether the GFCI can be backfed.

Outside of that you can not backfeed this circuit from a generator, you need proper transfer equipment and arranged so it can not backfeed the utility.
 
Tedh777 said:
Hi,
A quick question about the technical feasibility of reversing power flow through a GFCI breaker. The situation is for an installation of a pool heater fed from a sub panel in an outbuilding on a 30A GFCI breaker. The heater is disconnected and stored for the winter. There is a small backup generator, 30A, being wired in to the same outbuilding that will only be available in the winter (stored in the summer). I am just curious more than anything if the now unused GFCI breaker could be used for the generator as the pool heater is disconnected for the winter. I know reverse power on GFCI outlets will not work but am not sure about the same thing for breakers. Will power even flow through a GFCI breaker in reverse or will it trip? What are your thoughts on the circuit design in a GFCI breaker in this situation?

Thanks,
Ted
Click to expand...

Just a point I would like to make to add to Kwired's post above:

Back when Hurricane Charlie hit Florida three electricians decided it was a good idea to back feed houses from generators to get some peoples power back on the cheapest route they could find, these three electricians are now sitting in prison for involuntary manslaughter for 15 years each for killing three line-men who thought all power was out while trying to repair the power lines.

Myself I would not want to have that on my conscience even at the level of knowing that I had advised someone how to do it as it would be something I would have to live with for the rest of my life.

Do yourself a favor, never advise someone on how to back feed a house that could possible kill someone down the road, the utility transformer will transform up as well as down and if a generator is feeding into a circuit on a service and the owner forgets to turn off the main when connecting and running the generator it can back feed the utility transformer and kill a line man who might think the power is out, always only offer the right way of using the proper transfer equipment that will prevent this from happening, even if you are not doing the work, they could point the finger at you saying that you told them to do it this way, even if this doesn't happen would you want to live with the fact that you provided the info that caused this to happen?

Sorry for being so blunt but so many people are killed each year just because someone takes the cheap way out and does not do the job the right way, they never think of the outcome they could cause on others and the lives they can wreck when the provider of the house is killed because someone was too cheap to purchase the proper transfer switch.
 
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I just looked at you profile and seen you work for a utility, I'm very supprized that you would think of back feeding a house from a generator without using a transfer switch???,

If this is not what your trying to do then please disregard my post above.
 
hurk27 said:
I just looked at you profile and seen you work for a utility, I'm very supprized that you would think of back feeding a house from a generator without using a transfer switch???,

If this is not what your trying to do then please disregard my post above.
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I understand what you are saying here and in the previous post. I agree! I was looking at different options for a backup generator which will be fairly remote from the house and where a transfer panel is not practical. The idea that I have been working on would include a mechanical interlock. Two locks, one key, and the key cannot be removed from the lock while it is open. This is used frequently in our utility and could serve the same function for safety as a transfer switch. I am not liking the idea but considering it. The other option I am thinking would work is the GenerLink device from Global Power Products and a long cord option. (Anyone have experience with these? www.generlink.com) This is probably the way it will end up going as the sequence for powering up with the interlock and several switches is too cumbersome for most people in the situation where you would need to use it. Not too bad on a sunny day when you are just testing it out but different story in the dark during a winter blizzard.

In my job I am responsible for a great deal of workers safety and would certainly not want to do something outside of my job that is against that. I appreciate your bluntness and if you think I am doing something wrong hope you continue to call me on it.

Thanks.
 
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