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Ok, trying to figure out the right place for this, I know there are lots of folks on here with a diverse background so I thought someone might know.

As you may have heard Mich. got hit with High winds on Wed (sustained winds over 50 with gusts up to 65mph) this is the worst outage in Detroit Edison history. Anyhow, we have underground service and rarely lose power so never dealt with a generator. We lost power early on and with high's forcasted of 20F. I decided to buy a generator, so Thur morning I went to a local (higher end) place that still had some, Honda's only but anyhow they had something so I got a Honda EB3000C. Long story shorter, this is deemed a construction site generator so it has its Ground bound to the neutral and has GFCI on the outlets. Since it does cant backfeed house since it to has Ground bound to Neutral (which causes a loop and pops the GCFI instantly) ok so ran an extension cord / split to many things life good, but the furnace, hard wired in. Lucky there is a outlet right at it for the condensor pump. Turned off main, disconnected the ground going back to house. Plugged in generator, pop goes GFCI, I had to disconnect the ground into the furnace so now no ground, but it worked. However if I then add the Fridge or Freezer chest with grounds and the furnace, it would pop. Got some 3 prong to 2 prong adapters for those 2 lines and everything works. But nothing is grounded. But since its all being run of GFCI I feel safe.

So here is my question. To use this generator as a whole house (well 1 leg as its only 110) I can unbind the ground and neutral on the generator (well need to look at wiring and talk to Honda but have read that its doable). But my question is why cant I just not run a ground line. Just feed the load and neutral into the house. all the devices would still have ground lines in house. Hmmm but the house has the neutral to ground bound so would this take some of the load off the neutral and not feed back to generator and as such trip the GFCI?

Not looking at doing anything to current set up for this time, just thinking to be prepared if there is a next time. Everything is running well, now, and wife said this setup works. Just lots of extension cords running around the house.

To restate my questions.

1) Why does having nonground (furnace) and grounded (freezer chest and Ref/Freezer unit) cause the GFCI to go?
2) what is the danger in not having the devices grounded back to Generators GFCI outlet? (I don't think there are any)
3) Could I backfeed house with just the Hot and Neutral?

Thanks
 

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Discussion Starter #3
I don't know anything about generators but this can go in general off topic. It will receive more views there than in the Frontier. I can move it for you if you want Davhamm.
Sure, I must have missed the general off topic, section. got power back last night and slept 11hrs slowly returning to normal.
 

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Doesn't help most of you here but....

I've got a Chevrolet Volt that I installed a 1.5kW inverter in to power my house as a backup when we lose power. 16.5kWhr battery pack and the engine will recharge teh 12V supply that I connected the inverter too. Saved quite a bit of money over buying a separate generator system.
 

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Discussion Starter #6
Doesn't help most of you here but....

I've got a Chevrolet Volt that I installed a 1.5kW inverter in to power my house as a backup when we lose power. 16.5kWhr battery pack and the engine will recharge teh 12V supply that I connected the inverter too. Saved quite a bit of money over buying a separate generator system.
To bad I leased my Volt, I forgot about this. I looked into on my first Volt lease. But being a lease and that we don't lose power often, I never pursued it. 1.5KW would keep the fridge or freeze going, not sure it would handle the startup draw of the furnace. Probably would, but not with the fridge and freezer running at the same time.

But Would get you through the power outage. Just make sure you figure out how your getting the power into your house, before you lose power.
 

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The GFCI tripped because of the capacitance of the house wiring. "Charging" the house will fool the breaker into thinking there is a leakage to ground because the currents in the hot and neutral legs are not balanced.

I had the same problem when I was building my house and tried to test the wiring using the GFCI-equipped temporary power pole. I have been told that newer, better, GFCIs aren't as likely to do this, but haven't had reason to test one.
 

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Replace the GFCI recepticals in the generator with regular recepticals. I have no problem running everything in my house off the generator including the A/C with no problem at all

Joe
 

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Discussion Starter #9
Replace the GFCI recepticals in the generator with regular recepticals. I have no problem running everything in my house off the generator including the A/C with no problem at all

Joe
The GFCI is not in the receptacles its part of the main breaker on the generator. If I were to modify the generator I think the bonding line from neutral to ground is pretty easy to find and remove. I just don't see the point, or understand the risk I am taking by not connecting the generator ground to the house ground given that the power would be coming through that GFCI protection.

well I have had one explanation, which is the ground around the generator could become charged which would put a decreasing voltage rings around the base of the generator and if it was high enough, and you stepped in no insulated shoes across it you would get a zap. This happens with High power lines and has been known to kill cows. But I don't think the Generator ground would get that much of a raise over the local ground but might be worth considering adding a line and stake to ground the generator into mother earth better.
 

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The chance that the ground around the generator becoming above ground potential is slim to none. You're house service is grounded with a ground rod at the house and at the underground service box. It would be an abnormal fault with the power company's equipment to do that and it would be only for
an instant before the cutout would blow. I think you should contact the gen mfg.

Joe
 

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This isn't an answer to your question, but a few years back we got a natural gas 17kW generator wired into a GenTran. It runs everything in the house except the hot tub, with automatic transfer to and from the generator. When the power goes out it waits 30 seconds, then switches over.

It takes the adventure out of power outages, but the house sits below the sanitary sewer so it has a pump/grinder thing and with no power we had only 50 gallons of water usage before the tank filled. That was a show-stopper.
 

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I have another "guess". I don't know how you powered up the house. How did you power up the house? Did you shut off all of the branch circuits and then turn on the main breaker? Did it only trip the GFCI when you turned on branch circuits? Since the GFCI will trip when the current to ground is 5 milliamps or more, it could be that you have a branch circuit that has a fault to ground that is more then 5 mills but not enough to cause any problems. When that breaker is turned on it would trip the GFCI.

Joe
 

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Discussion Starter #13
The chance that the ground around the generator becoming above ground potential is slim to none. You're house service is grounded with a ground rod at the house and at the underground service box. It would be an abnormal fault with the power company's equipment to do that and it would be only for
an instant before the cutout would blow. I think you should contact the gen mfg.

Joe
What am i going to ask them? you lost me somewhere, why am I contacting the Generator Manufacturer?
 

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Discussion Starter #14
This isn't an answer to your question, but a few years back we got a natural gas 17kW generator wired into a GenTran. It runs everything in the house except the hot tub, with automatic transfer to and from the generator. When the power goes out it waits 30 seconds, then switches over.

It takes the adventure out of power outages, but the house sits below the sanitary sewer so it has a pump/grinder thing and with no power we had only 50 gallons of water usage before the tank filled. That was a show-stopper.

Oh yeah, with my wife, if we lived in a location that lost power with any frequency we would have an automatic whole house natural gas generator no if ands or buts about it. But since this is only the 4th significant (more than 30 min) power outage we have had in 26yrs never thought we needed one. But this time saw the weather dropping into below freezing for days and the largest weather related outage our electric company has had, I knew we needed a geny just to get through those few days. May never actually run it again, but it made those days livable.
 

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Discussion Starter #15
I have another "guess". I don't know how you powered up the house. How did you power up the house? Did you shut off all of the branch circuits and then turn on the main breaker? Did it only trip the GFCI when you turned on branch circuits? Since the GFCI will trip when the current to ground is 5 milliamps or more, it could be that you have a branch circuit that has a fault to ground that is more then 5 mills but not enough to cause any problems. When that breaker is turned on it would trip the GFCI.

Joe
Joe, I am not sure what problem you are trying to figure out. I know why the GFCI blew when I didn't disconnect the ground in the furnace (to the house) and why I can't backfeed into the house. Both the house and the generator have the Ground and neutral connected to each other, So that makes a completed circuit, and instead of all that goes down the hot, coming back the neutral some will come back via the ground, which means the GFCI which is looking for differences in hot and neutral we see that and instantly blow.

I have since learned the Furnace will also be grounded to the gas pipe, which more than likely has other grounds to it (Water heaters) and therefore that was completing the same circuit and blowing.

The 2 questions I have left.

Why does having an ungrounded appliance and grounded appliance on a GFCI cause a GFCI to blow ( I could actually try this with my regular GFCI outlet tonight to confirm)

and the main one.

What is the risk of running my Geny in the future with just the hot and neutral running into the house and feeding the appliances (since it is a GFCI there is no risk of shock).
 

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A GFCI has circuitry that will trip if it detects that the load-side neutral is grounded, regardless of current flow.
Also, many refrigerators, bathroom exhaust fans, and fluorescent lights will trip GFCIs because of their inherent leakage current and are therefore not recommended to be GFCI protected.

The best solution is to use a generator without a GFCI and back-feed your panel box through a branch breaker that is interlocked with the main.
 

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You shouldn't have to disconnect the ground at the furnace. That is why I am suggesting that you contact the gen mfg. I'm not there and can only speculate what the problem may be.

Joe
 

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In every house I have seen, the neutral is bonded to the ground at the panel box. If you connect a GFCI-equipped power source (eg: generator) to a circuit with a bonded neutral you will trip the breaker because it is designed to trip under those conditions. That means that you cannot connect such a generator to the panel box. You also cannot connect it to anything that may have a connection between the neutral and the ground that will allow more than 5mA of current, which at 120VAC means approximately 24,000 ohms of resistance. A lot of appliances and fixtures can experience that amount of leakage current, and refrigerators are among them.

Disconnecting grounds is not a good idea under any circumstances, and you can still get a pretty good shock from a GFCI protected circuit under some conditions, particularly if you have created a floating neutral by removing the ground.
 
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