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Discussion Starter #1
Greetings generator friends,

I have a pair of inverter generators (2400 watts surge each) and I am wondering what risks, dangers, lectures, etc. I will be subject to if I backfeed into my panel with each generator lighting up one side of the panel. The panel is split with all 240v breakers on top including one that feeds the bottom half of the panel which is all 120v breakers. By shutting off the 240 breaker feeding the bottom half of the panel the 120v circuits on each half of the panel of course are separated except where the neutrals are tied together. To be clear, with this scenario I would only be feeding 120v breakers, half with one generator and half with the other.

TIA,
Blane
 

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None of your 240 stuff will work with that. And more importantly, you forgot to mention the most important thing if you are doing this: TURN OFF THE MAIN BREAKER. It's waaaay too easy to forget to do that, and if you do, you could electrocute some poor lineman out there up on a pole trying to get your power back on.

Now, if you put a proper interlock between the main breaker and your backfeed breaker that will positively prevent backfeeding to the utility, that's a different story.
 

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Discussion Starter #4
Thanks for the replies guys.

Old man, would you mind explaining your reasoning behind your answers. To the uniformed your answers are very appropriate but I have been back feeding my panel every power outage of any length for the last 30 years and since I am extremely careful I have not had a single incident. I do not run cords into the house as open doors and/or windows creates a security issue.

Motormonkey, I forgot to mention that I do not have a main breaker in the panel. I always pull the meter from the socket when I backfeed the house. I understand that I cannot run anything with 240v and that is okay. Even if I could the little inverter generators are not powerful enough for the water heater or the oven.

I have set up my house with dedicated backfeed circuits to the rear of my house. There is nothing on these lines other than a receptacle at the exterior. I ran #12 wire which will handle more than each generator will produce.

My question is, what is the harm, if there is any, of running a separate generator to each side of the panel when there is no "cross contamination" of the two sides other than where the neutrals tie together. Since the neutrals tie together both sides of the panel when operating with utility power how is what I am proposing to do any different?

Thanks again,
Blane
 

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Personally, I would not backfeed electricity into my house circuit without a positive interlock in place to eliminate all possibility of energizing the utility line. The consequences of you, (or someone else,) failing to turn the main breaker off or remove the power meter are just too serious.

Also, the neutral and ground conductors in your home's electrical system are bonded together at a single point somewhere in the system. It is not a good idea to have a second bonding point in the system, such as within the generators. Generators commonly come from the factory with these conductors bonded. These bonding jumpers should be easy enough to remove.

Aside from these two issues, there is no harm in doing what you propose.

BTW, how do you get by with removing your power meter? Here, the power company has their seal on the meter box and they get upset if it is disturbed.
 

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Discussion Starter #6
Thanks for your reply Motormonkey confirming what I thought but didn't know for sure. My little inverter generators are each a Honda EU2200i. They have a floating neutral so there isn't an issue of having two places where the neutral is bonded to the ground (it will only occur at the main panel).

To answer your question after removing the meter from the socket during a power outage I call the power company up to reseal it after my power is restored. The customer service representative simply asks if I did any work on my electric system when the meter was removed, I say no, and then they tell me they will send out an inspector to reseal the meter. I have been told by a power company lineman that they appreciate when a meter is pulled by a homeowner while they are running a generator. Whether this is a company wide policy or not I don't know.

Thanks again,
Blane
 

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WOW!
yea here in Iowa and Illinois they have strict rules on removing meters.
even as an electrician they want to be the ones doing a pull and re install of the meter here.

if you cut a meter or box tag here the fines start at $500.00 and run up to jail time.
part of that diversion rules they now have....

too many contractors were connecting with a fake meter....

but if you call them and ask for a meter removal or line snip.
now days they have less of a time wait!
i think i was at 1/2 an hour till there were here....
the line man even waited the 15 min for me to complete the tie in jumpers to the new outside disconnect.

I have pad locks on both the meter and the disconnect box now...
they agreed and like the idea!
that way we both have to be there for a removal or shut down of power.
and it keeps meter theft or some one trying to shut down power to the property.

yea there was a bunch swapping out meters here in Iowa!
so take pix of you meter serial number and make sure it matches your utility bill!

they caught a bunch of them in the des moines area...
random traffic stop too!
you have got to love profiling!!
lol!
white van, in a residential location... out of county plates!
at least the cops were watching!!
 

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Thanks for the replies guys.

Old man, would you mind explaining your reasoning behind your answers. To the uniformed your answers are very appropriate but I have been back feeding my panel every power outage of any length for the last 30 years and since I am extremely careful I have not had a single incident. I do not run cords into the house as open doors and/or windows creates a security issue.

My little inverter generators are each a Honda EU2200i. They have a floating neutral so there isn't an issue of having two places where the neutral is bonded to the ground (it will only occur at the main panel).

My question is, what is the harm, if there is any, of running a separate generator to each side of the panel when there is no "cross contamination" of the two sides other than where the neutrals tie together. Since the neutrals tie together both sides of the panel when operating with utility power how is what I am proposing to do any different?

Thanks again,
Blane
I think it's very different.

Your utility power supplies two hots that are each 120V to an earth-referenced ground, but 240V between them. Your panel neutral is earth referenced at the main panel.

Someone correct me if I'm wrong, but I don't think your generators really have a "neutral", rather they have two hots that are each 60V to an earth-referenced ground, but 120V between them. I think your "neutral" prongs will each have 60V on them. If that's the case, I think there would be problems when you wired each of them to the panel neutral.

At the very least, if you're gonna try this, fuse each conductor from the generators to the panel. Better to fry some fuses rather than the generators or your panel.
 

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Thanks for the replies guys.

Old man, would you mind explaining your reasoning behind your answers. To the uniformed your answers are very appropriate but I have been back feeding my panel every power outage of any length for the last 30 years and since I am extremely careful I have not had a single incident. I do not run cords into the house as open doors and/or windows creates a security issue.

Motormonkey, I forgot to mention that I do not have a main breaker in the panel. I always pull the meter from the socket when I backfeed the house. I understand that I cannot run anything with 240v and that is okay. Even if I could the little inverter generators are not powerful enough for the water heater or the oven.

I have set up my house with dedicated backfeed circuits to the rear of my house. There is nothing on these lines other than a receptacle at the exterior. I ran #12 wire which will handle more than each generator will produce.

My question is, what is the harm, if there is any, of running a separate generator to each side of the panel when there is no "cross contamination" of the two sides other than where the neutrals tie together. Since the neutrals tie together both sides of the panel when operating with utility power how is what I am proposing to do any different?

Thanks again,
Blane
Blane,

Please don't do it. You are NOT eliminating the "cross contamination" of the two sides. The two sides and two generators need neutrals and you are making them share the single house neutral; so they can "cross contaminate". I can't give an expert explanation of why your plan won't work, but I can say that the two "hot" wires coming into your house from the power company are not independent; they are a single phase and come from a single physical source which assures that the timing/alternation of the two alternating power streams can offset properly on the neutral. Just combining all the neutrals will not guarantee that precise offset will happen; two independent generators combined can produce a totally weirdo waveform and damage the generators and your appliances.

The single/shared neutral wiring in your home works OK with utility power because the single voltage phase is locked together by the generation of the two 120 feeds. In the utility case, its more like a single 240V source is split in half with each side keeping the same timing beat to assure the coordination.

But ... you mention that these are inverter generators. Inverter generators CAN be combined with a "parallel kit". into a SINGLE 120V source; in your case you should be able to produce a single 120V, 4400 Watt source using the two generators connected through the parallel kit. The output of the parallel kit is one hot wire, one neutral and one ground. I believe this works with inverter generators because they have enough smart electronics to coordinate the timings of the two generators via a parallel controller and make sure they are precisely aligned and do not "cross contaminate" each other.

Here's something you might want to look into; use a parallel kit to create one voltage source, then feed the single parallel kit "hot" into both hot sides of your house in parallel. (Turn off all your 240V circuit breakers as well as disconnect from the utility grid). I have to tell you that I considered doing this personally, but wasn't TOTALLY confident it was 100% safe. 95% maybe. Even if it is more-or-less safe; I doubt that it is legal. I have no personal experience with parallel kits; it appears they are manufacturer and even model specific. Here's some info for your generator model:
Amazon.com : Honda EU2200i 2200W 120-Volt Portable Inverter Generator with Companion and Parallel Cables : Home Audio & Theater
Looks like it is just cables; but other brands parallel kits are cables and a control box. Maybe give Honda a call and see what they advise. Wow; looking at this picture on the Amazon site I see that the two generators shown are slightly different; one is labelled EU2200i Companion and has different sockets. Definitely proceed with caution.

I would love to know if this approach works but I don't have the nerve to try it personally, or the wallet to get myself back online if it smokes. Please let us know what happens if you try it out :)
 

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Inverter generators CAN be combined with a "parallel kit". into a SINGLE 120V source; in your case you should be able to produce a single 120V, 4400 Watt source using the two generators connected through the parallel kit. The output of the parallel kit is one hot wire, one neutral and one ground.
Is it? I'm pretty sure that the output of the individual generators is actually two hots and a ground. I have no idea if the parallel kit changes things (it might in the case of these Honda's, with the special "companion"), but I would guess that most of them do not.

So, if he really has two 60V hots, and tries to wire one of them up to an earth referenced ground, I'm pretty sure that some of the magic smoke is going to come out somewhere.
 

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if he really has two 60V hots
No. If you parallel two 120V inverter generators, you have a single 120V hot to neutral at the sum of the generators amperages.

If you're dealing with 240V, you have two 120V hot to neutral lines, but they are 180 degrees out of phase with each other, so the voltage between them is 240V.
 

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Is it? I'm pretty sure that the output of the individual generators is actually two hots and a ground. I have no idea if the parallel kit changes things (it might in the case of these Honda's, with the special "companion"), but I would guess that most of them do not.

So, if he really has two 60V hots, and tries to wire one of them up to an earth referenced ground, I'm pretty sure that some of the magic smoke is going to come out somewhere.
Nebrasky, Are you saying that the double 60V hot system is true of generators in general, including conventional? Or just inverter types? People have been backfeeding their houses (illegally) with generators for a long time without (always) smoking their house electrical system, and backfeeding does indirectly connect the generator to an earth ground. (Its not a good idea to backfeed; they risk dangerous electrical shocks to themselves and utility workers, but it can produce electricity without smoke). So I don't think the earth referenced grounding itself is the issue here. Most generators can work in a floating or bonded neutral configuration and connect to their own ground rod. (But ground rods are only done in special circumstances; don't do it. Call an electrician). But if there really are two 60V hots as you say, something keeps them on exactly the same timing/heartbeat/phase so that the alternating 60V sources combine to 120 all the time. Just like tabora's chart that shows two 120s combining to produce 240. The 240 wouldn't work right if the two 120s were not in the same phase. I do agree with you that neutral in a generator is not quite the same as the neutral as we understand it in our house and that generation of 120V in a generator is not as simple as a Hot and Neutral wire.
 

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From my understanding, and I'm certainly no expert, both terminals on a floating neutral generator are hot OR read voltage as per the following link: (OR is it simply stray coupling??)

Differences Between Bonded and Floating Neutral Generators.

I started a thread a while back in regards to combining my neutral and ground and the thread can be found here: Floating Neutral

I'm aware my thread was a somewhat different subject, but maybe it can help. However, in my case, I ONLY run the generator in a standalone mode. But, BEFORE tying the neutral to ground, I did get a reading of approximately 60 volts when reading EACH of the receptacle's terminals to the ground of the generator.

Please disregard this post if it is irrelevant! I'm trying to understand all of this generator stuff myself and I am following closely!
 

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Nebrasky, Are you saying that the double 60V hot system is true of generators in general, including conventional? Or just inverter types?
I'm talking only about 120V inverters, and specifically the Honda 2200i's that the OP has. I have a Predator clone of that generator, and mine is a split-phase 60V hot system. It's exactly like tabora's chart, except that instead of +120 and -120 combining to make 240, you have +60 and -60 combining to make 120.
The two lines from a single generator must be kept in phase, as you say, so that they always combine to 120V. But, unless you have the proper paralleling connection between the two generators, there is nothing keeping the lines from two different generators in phase. The OP wants to take one line from each generator and tie them together at the panel neutral. If they are both 60V hots, as I understand it, I would think that would be a problem.
Now, I have never tried to earth reference my invertor generator's neutral. TVL's thread is an interesting experiment. He said that both the lines on his invertor generator measured 60v to ground BEFORE he tied the "neutral" to the ground. But after bonding, the generator apparently continues to function normally. I have no idea what's going on there. I'm very curious what the other outlet voltage measures now, after he plugs in his bonding plug. Maybe the generator electronics can shift to a 120V hot/grounded neutral system. I don't know.
I may have to make up my own bonding plug now, and try it with my generator. Except I'm going to fuse that bond.

Even aside from all that, I don't think that what the OP wants to do is safe under any circumstances. Let's say that he's got two conventional generators, each with a 120V hot and a bonded earth-referenced neutral. Unlike the utility power, there's absolutely nothing keeping those hots in phase. So current from generator A is going to run to bus A on the panel. Whenever the OP uses an appliance on that bus, the current flows through the appliance to the neutral bus. Same thing for generator B and bus B. But the currents from the two different generators are not in phase at least half the time. If he's using 1500 watts from both generators, he could end up with 3000 watts on the panel neutral. And likely there would be wildly fluctuating voltages and amperages as the two generators move in and out of phase. I would think that would create problems that way as well.
But I could be completely wrong about that. I do think it's worth thinking about.
 

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I'm aware my thread was a somewhat different subject, but maybe it can help. However, in my case, I ONLY run the generator in a standalone mode. But, BEFORE tying the neutral to ground, I did get a reading of approximately 60 volts when reading EACH of the receptacle's terminals to the ground of the generator.
So what do you get now for volt readings!?!
 

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Discussion Starter #16
If there is something magical in the inverter generators that when combined together using simple cables supplied by the manufacturer synchronizes the generators phases why couldn't that conductor connection instead occur at the panel through an otherwise unused 240 breaker shorted together? If this were done wouldn't the 120 circuits (which are the only circuits being powered) on both sides of the panel's neutrals be fine tied together since they would all be in phase? Sure this would create an unbalanced load but we only talking about 30 amps max being sent back out the panel's neutral feed. I am sure that size of load occurs a lot of the time when the panel is powered by the utility grid.
 

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If there is something magical in the inverter generators that when combined together using simple cables supplied by the manufacturer synchronizes the generators phases why couldn't that conductor connection instead occur at the panel through an otherwise unused 240 breaker shorted together? If this were done wouldn't the 120 circuits (which are the only circuits being powered) on both sides of the panel's neutrals be fine tied together since they would all be in phase? Sure this would create an unbalanced load but we only talking about 30 amps max being sent back out the panel's neutral feed. I am sure that size of load occurs a lot of the time when the panel is powered by the utility grid.
They are not simple cables. This picture is from the Amazon site. Note that the label on the generator says "special cables" and they plug into specific spots. I believe there is circuitry inside the generators that perform the synchronization, but only when they are plugged together in this specific way. The parallel kits themselves are not expensive, so it wouldn't be worth trying to create a workaround to obtain their functionality if that is what you are trying to accomplish. The remaining question to me is ifconnection to earth grounding causes the problem Nebrasky suspects. (Messing up the 60+60 design of the generator).
8605
 

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bwswede ... you say you have a pair of generators already. Do you have the "companion" pair and or a parallel kit/cable of some kind?
 

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If there is something magical in the inverter generators that when combined together using simple cables supplied by the manufacturer synchronizes the generators phases why couldn't that conductor connection instead occur at the panel through an otherwise unused 240 breaker shorted together?
A parallel kit has additional wiring that plugs into the parallel ports on each of the generators to allow synchronization. Were you planning to wire that up as well?

If this were done wouldn't the 120 circuits (which are the only circuits being powered) on both sides of the panel's neutrals be fine tied together since they would all be in phase? Sure this would create an unbalanced load but we only talking about 30 amps max being sent back out the panel's neutral feed.
If the wiring can handle it, that's fine.

I'm not trying to be argumentative. All that I really know is that my invertor generator, and probably yours as well, produce a split-phase 120V that has 60V on each side of the 120V wiring. When you wire that up the way I think you're suggesting, I don't think you're going to get 120V at the house sockets. Maybe you will, I haven't tried it. It just seems like you're more likely have some pretty wildly gyrating voltages anywhere from 60 to 180v, if you don't fry something first. Hence my suggestion of fusing every conductor from the generators.

You might be fine, I don't know. I just don't see how hooking up a 60v hot to one side of your panel and an unrelated 60v hot to the other side is going to give you normal 120V on your house circuits.
 

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Not being as knowledgeable as almost everyone else on this forum, I'm a little hesitant to make any type comment. However, because of some research, I would like to make mention of the floating neutral generator's that are out there in the world ................ such as my Honda EU3000is:

1) On a floating neutral generator the following is true AND the following is a quote form an article I read: "In a floating neutral generator, since the neutral is not bonded to the generator’s frame, both wires are normally current carrying wires. Therefore, both slots of the receptacles on the generator are considered live/hot receptacles."

2) It's my understanding these type generators are shipped with floating neutrals because it appears it is expected these generators will likely be connected to a home's service panel. Once this is done, the neutral becomes bonded to the ground at that point. Why? ......... as most here already know, the neutral AND ground connections in a home's service panel are tied together OR bonded!

3) Bonding at the generator AND the service panel creates ground loops ................. which is another subject in itself. I guess Honda took the safest approach and shipped the units with a floating neutral because it eliminates the possibility of bonding in two different places, if the unit is truly to be connected to the home's service panel. However, although the generator can be run in standalone mode with a floating neutral, it also presents other issues .................. which again, is another subject in itself.

4) The main thing I wanted to point out in regards to bonding a neutral to the ground lug of a generator is as follows:

A- If a generator with a floating neutral is connected to a home's service panel, it is then no different than running the unit in a standalone mode with the neutral tied or bonded to the ground lug of the generator. (As a side note: in this case it is also important to have the standalone generator connected to an appropriate ground rod!!)

B- I had to draw this out in order to "see" that it's the same thing. Visualize your generator being tied to your home's service panel. Again, visualize how the neutral wires AND the ground wires are all tied together inside the service panel. They are truly bonded! If these two wires are tied together OR bonded OR jumpered in the service panel, then they are in essence tied together in the generator as well. In other words, when one operates a floating neutral generator as a backup unit (tied to the home's service panel), the bond occurs at the service panel box. The bond OR jumper truly exist, it is simply inside the service panel some distance away from the generator. Therefore, why can't one run a floating neutral generator in standalone mode with a bond or jumper at the unit? They can because it's the exact same either way you do it AND it also makes the generator a little safer this way .................... which goes back to my other thread.

My post has likely "muddied the water" from the OP's original intent, but I am trying to help address what appears to be a concern with bonding a generator. Unless I've interpreted some of the messages incorrectly, it is permissible and safe ................... at least from all of my research!
 
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