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That 60 volts on both line and neutral could just be due to voltage being coupled through some fairly low value line filter capacitors between line/ground and neutral/ground in the generator's output. That's commonly done.

Apply some kind of load, such as a hundred watt incandescent light bulb, between neutral and ground, and I'll bet that neutral/ground voltage will drop to zero or very near zero. If it does, you're okay to ground the neutral.
That's what I was alluding to earlier: stray coupling - however, that was based on another individuals findings and I was simply "riding on their coattail".
 

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That 60 volts on both line and neutral could just be due to voltage being coupled through some fairly low value line filter capacitors between line/ground and neutral/ground in the generator's output. That's commonly done.

Apply some kind of load, such as a hundred watt incandescent light bulb, between neutral and ground, and I'll bet that neutral/ground voltage will drop to zero or very near zero. If it does, you're okay to ground the neutral.
Perhaps that would be the case on the Honda's, I can't speak for them. It's not the case on my Predator 2000. I played around with the oscilloscope this evening. I may not have all the settings figured out correctly just yet.
But WOW, is this predator BAD!!!
These probes are wired up so that the green/yellow channel is connected to the nominal "hot" prong of the 120v plug and the purple channel is connected to the nominal "neutral" prong. A three-way splitter pigtail is plugged into the generator, then a heater is plugged into one of those outlets and the probes are plugged into another of them.
First picture is no load, the heater is turned off.
8614


Second picture, the 600 watt element on the heater is turned on:
8615


Third, both the 600 watt and the 900 watt elements are both on:
8616


We were playing around with it, and this picture is with the pigtail plugged into the utility mains and a small squirrelcage fan is running. So, in this case, the green line is the utility power, and the purple line is the return voltage on the bonded neutral. They aren't magnified the same in this image, but you can compare the utility main to the predator signal.
8617

These pictures were taken while we were figuring out the oscilloscope and just playing around with it. Tomorrow I need to do a more serious study with it, and make sure all the settings are consistent.
 

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Readings at the bottom of your scope indicate a voltage of ~ 5.60V
You're looking for a much greater voltage than that .................... correct?

As motor monkey has stated; it is likely just coupling OR phantom voltage!

IF I'm interpreting your scope correctly, the scope is setup for 10 Volts per division meaning the sine wave is only approximately 20 Vpp??????
 

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I don't have an RV, but I think that the 30 Amp plug on bwswede's Companion generator is designed to connect to a standard 120V RV electrical system inlet box in a simple/standard way. If we understood the manufacturer's intentions when designing generators to support RVs out of the box, we might get some clues on how to use such a generator on a house. Does an RV have a neutral convention? I'm assuming that it has a ground that is bonded to the metal shell of the RV. Is that bonded to the neutral? I don't think an RV uses a ground rod, so I wouldn't expect the RV to have an analog of the house neutral to earth ground bonding.

I am very curious to know what the 120V (only) inverter generator manuals say about "neutral". I don't have any generators like this. Do they ever use that term? I'm looking at the pictures of bwswede's pair of hondas; the Companion says "Neutral floating" near the 30A outlet but I can't tell which slot, if either, is considered neutral. The 20A outlet looks like it has a slot that is hot and a slot that is neutral, but its not clear from the picture how/if they align with the two "hot" slots on the 30A outlet. Does the polarity implied by the slots on the standard 20A outlet really mean anything or is that just that just to accommodate a variety of plug types. (Do the two 20A outlets even have the same polarity?)

Do the manuals (or online resources) for these types of gens describe a process for bonding the neutral of the generator? How about an attachment point for a ground rod? Or even warnings that bonding and ground rods should not be attempted?

Sorry to pose all these questions, bwswede. I do think its possible to accomplish what you are trying to do, but risky. I went through a similar thought process several months ago but got cold feet and bought an open frame 120/240 inverter gen for my house that didn't pose these challenges in the hook-up. I don't use anything 240 in my house except the AC, and I don't think my gen is really big enough to support AC without turning off some other important stuff. It was disappointing to sacrifice the additional quietness and flexibility of the smaller generators to get the hookup I do need along with the 240 I don't need, but I don't worry about getting smoked!
 

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Perhaps that would be the case on the Honda's, I can't speak for them. It's not the case on my Predator 2000. I played around with the oscilloscope this evening. I may not have all the settings figured out correctly just yet.
But WOW, is this predator BAD!!!
These probes are wired up so that the green/yellow channel is connected to the nominal "hot" prong of the 120v plug and the purple channel is connected to the nominal "neutral" prong. A three-way splitter pigtail is plugged into the generator, then a heater is plugged into one of those outlets and the probes are plugged into another of them.
First picture is no load, the heater is turned off.

Second picture, the 600 watt element on the heater is turned on:

Third, both the 600 watt and the 900 watt elements are both on:

We were playing around with it, and this picture is with the pigtail plugged into the utility mains and a small squirrelcage fan is running. So, in this case, the green line is the utility power, and the purple line is the return voltage on the bonded neutral. They aren't magnified the same in this image, but you can compare the utility main to the predator signal.
These pictures were taken while we were figuring out the oscilloscope and just playing around with it. Tomorrow I need to do a more serious study with it, and make sure all the settings are consistent.
You are measuring voltages between line and neutral, with the expected normal results. (noisy as they may be) That does not indicate anything about the voltages between line/ground and/or neutral/ground, which are what is in question here.

Voltage between neutral and ground may well be 60 volts because there is no current flow between these conductors the way you have it wired. To see if the line/neutral circuit is actually floating, you would need to apply some minimal load between neutral and ground, and then measure the voltage across those conductors.
 

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You are measuring voltages between line and neutral, with the expected normal results. (noisy as they may be) That does not indicate anything about the voltages between line/ground and/or neutral/ground, which are what is in question here.

Voltage between neutral and ground may well be 60 volts because there is no current flow between these conductors the way you have it wired. To see if the line/neutral circuit is actually floating, you would need to apply some minimal load between neutral and ground, and then measure the voltage across those conductors.
One channel is measuring line to ground and other channel is measuring neutral to ground. Two separate grounded probes, two separate channels. The grounds for both probes are hooked up the generator ground. I didn't expect back feeding there to cause much problem. It didn't actually change the picture much when I unhooked the grounds.
I do not have probes hooked up line to neutral. I had 600 watts load between line and neutral in the second picture, 1500 watts in the third picture.

You want me to connect a 60watt incandescent bulb between neutral and ground? Hook it up so that the "line" , normally black wire, of the light fixture connects to the "neutral" conductor coming from the generator? And the neutral, normally white wire, of the fixture connects back to the rounded ground prong of the generator?

I can do that, just wanted to make sure I understand what you mean. If I do that, what voltage readings are you interested in seeing? I'd probably just use the multimeter in that case.
 

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Readings at the bottom of your scope indicate a voltage of ~ 5.60V
You're looking for a much greater voltage than that .................... correct?

As motor monkey has stated; it is likely just coupling OR phantom voltage!

IF I'm interpreting your scope correctly, the scope is setup for 10 Volts per division meaning the sine wave is only approximately 20 Vpp??????
There's a 10X reduction on those numbers, and some of the other setting aren't ideal either. Don't pay too much attention to them at the moment. I'll try to straighten it out this afternoon. Maybe the picture will change.


Earlier, before getting out the oscilloscope, I had plugged the heater directly into the generator and watched voltages with the multimeter. At 600 watts of load, the multimeter still showed approximately 60 volts between either flat prong and the ground. At 1500 watts of load, the multimeter showed voltages spiking as high as 90/30 before drifting back down to 60/60.
So, I do need to play around with this some more and make sure I'm reading things correctly.
 

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You want me to connect a 60watt incandescent bulb between neutral and ground? Hook it up so that the "line" , normally black wire, of the light fixture connects to the "neutral" conductor coming from the generator? And the neutral, normally white wire, of the fixture connects back to the rounded ground prong of the generator?
That is exactly what he is implying. Once the bulb is connected in this manner, if we are truly "seeing" phantom voltage - which I do believe is the case, then the voltage reading will drop from ~ 60 VAC to approximately 0 VAC.

Therefore, your reading of ~ 60 VAC will be seen BEFORE connecting the bulb and then a reading of approximately 0 VAC will be seen AFTER loading the circuit with the bulb. Again, the bulb is put in the circuit between the neutral slot of the receptacle and the ground slot. You can also do this between the hot and ground as well and report your voltage readings. I do believe you will find both scenarios go to 0 volts.

Again, I'm assuming you're experimenting with a floating neutral generator as is the case with mine.
 

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There's a 10X reduction on those numbers, and some of the other setting aren't ideal either. Don't pay too much attention to them at the moment. I'll try to straighten it out this afternoon. Maybe the picture will change.
Oh!!!! You probably didn't have the correct probe setting selected in the scopes software!!!!!
 

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Oh!!!! You probably didn't have the correct probe setting selected in the scopes software!!!!!
No, the probe settings and the scope settings didn't match. Which may have been much of the problem. The manual for the scope is not that helpful, I'm rewatching a few youtubes to get all the settings sorted out.
 

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I'm rewatching a few youtubes to get all the settings sorted out.
I'm not sure how familiar you are with scopes, but the following video is a must see if you're new to this type equipment. Otherwise, please just disregard it.

 

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...

You want me to connect a 60watt incandescent bulb between neutral and ground? Hook it up so that the "line" , normally black wire, of the light fixture connects to the "neutral" conductor coming from the generator? And the neutral, normally white wire, of the fixture connects back to the rounded ground prong of the generator?

I can do that, just wanted to make sure I understand what you mean. If I do that, what voltage readings are you interested in seeing? I'd probably just use the multimeter in that case.
Yes, that is exactly what you need to do, and yes, measure the voltage across the light bulb, from ground to neutral.
 

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I'm not sure how familiar you are with scopes, but the following video is a must see if you're new to this type equipment. Otherwise, please just disregard it.

Yeah, I hadn't watched that one, but I did watch ElectroBOOM's video on scopes. He covered that part pretty well.
 

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Yes, that is exactly what you need to do, and yes, measure the voltage across the light bulb, from ground to neutral.
Hopefully this adventure will be helpful to others as well. It's educational for me, for sure.

I got the bulb hooked up and it doesn't light up. There's some voltage reading across it, the volt meter jiggles around a bit but stays under 5. So it's not enough to light anything up.
With the bulb plugged in, line to ground reads 124 or so.
Without the bulb plugged, the ESP surge protector won't transmit current. With the bulb plugged in, it does. Presumably, the voltage on the neutral triggers something in the ESP and shuts it down.
So bonding the neutral does indeed straighten out the signal generation. The oscilloscope shows a much better looking signal than before. And it's filterable. Running it through the ESP gives a perfect looking signal that's actually better than the utility mains.

Editing to add pictures:
For reference, this is a sample of the unbonded voltage output with no load.
8618


Ugly nastiness. Nothing lines up. In the picture above, the scope settings are correct so it gives the correct voltages.
It doesn't get much better when you plug in a normal tool or load. At least they're more synchronized, but it still can't be good for tools or electronics:
8619


But go ahead and bond earth-neutral, and voila!
8620


Still a little fuzzy at the peaks, but not bad.
Let's zoom in on a peak.
8621


What do you guys think? Good enough? I noticed the scope wasn't sure how to count the hertz, ended up counting all the little harmonics(?) to come up with 129Hz. But we're zoomed in pretty far here.
However, I have ESP power conditioners. Here's what comes through when you plug that into the bonded generator.
8623


That's perfect, even if we did lose a couple volts.
Pretty smooth now:
8624


Compared to utility power:
8625


8628



So it's probably very possible to set up two generators as the OP originally suggested, as long as the wiring and grounding can handle the completely unbalanced load.

My last question would be in the construction of a grounding plug. Is it better to wire up a dead short between the neutral and ground to bond the generator, or better to wire in a resistor in place of the incandescent bulb?
 

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if you are doing a generator as a stand alone power for an rv you are supposed to have a green ground stake at the generator. this makes the chassis as referenced to the ground at the generator location.

on a house setup with a floating chassis generator, the green ground is connected to the main panel that has all of the green ground as proper.
one ground for the whole house thing.
they bond the neutral to green ground in the main box to nec code.
 

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My last question would be in the construction of a grounding plug. Is it better to wire up a dead short between the neutral and ground to bond the generator, or better to wire in a resistor in place of the incandescent bulb?
is this for rv use or for home back up power or for a construction site?
 

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is this for rv use or for home back up power or for a construction site?
The primary use is going to be at work sites. I can't imagine that ugly non-bonded signal is going to be good for battery chargers or any other tools. That would be where I'd need the bonding plug. It might be ok for engine block heaters to be plugged into that nastiness, but I'd rather not even do that.

The freezer and fridge in my house are on the same circuit, and I had hoped to set up a switch to use this generator to power just that circuit. The neutral and ground would both flow back to the main panel in that case. That bond would give the same function as the bulb that I had wired up, correct?
 

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if you are doing a generator as a stand alone power for an rv you are supposed to have a green ground stake at the generator. this makes the chassis as referenced to the ground at the generator location.

on a house setup with a floating chassis generator, the green ground is connected to the main panel that has all of the green ground as proper.
one ground for the whole house thing.
they bond the neutral to green ground in the main box to nec code.
iowagold; I've been trying to understand RV elec systems and ran across this article;
RV Electricity – Generator grounding and bonding - RV Travel
That guy says " You DO NOT need to use an earth “grounding rod” for any portable generator that’s powering a single RV. However, if you’re using a large generator to distribute power to a number of RVs for a rally, that’s an entirely different thing which will require a grounding rod. "
This seems like a pretty knowledgeable guy. But he also says "The simplest way to Ground/Neutral bond a generator is to use the G/N plug I invented. Just plug it into any 15- or 20-amp outlet on the generator panel and it will bond the entire generator’s electrical system. Here’s a link to where you can purchase one. " I don't know exactly what he means by "bond the entire generator's electrical system". But taken literally, I'm pretty sure that's a bad idea! :)
I always try to keep in mind that intentional grounding is done to make the most likely shock hazard for the application less likely to happen, but it doesn't eliminate all hazards and can even create shock hazards that would not otherwise exist.
 

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My last question would be in the construction of a grounding plug. Is it better to wire up a dead short between the neutral and ground to bond the generator, or better to wire in a resistor in place of the incandescent bulb?
Excellent work! Your findings do match what I've seen as well. I think bonding is the right thing to do when a gen set is used in a standalone mode AND I feel a ground rod is also necessary along with the bonding ................. which is what I do!!!!!! If I encounter a ground fault, I certainly want a good ground!

In response to your last question: From my research, and I've done a LOT, I saw where one individual utilized a 100K ohm resistor with a 1/4 watt rating placed across the neutral and ground in place of a solid piece of wire. It worked fine like this, but I'm sticking with the solid piece of wire myself and here's why:

1) I don't want to lose that neutral/ground bond once it's made. I wouldn't trust a resistor in this situation .................... solid wire is much better!

2) From my research, I have discovered there are at least two reasons why some manufacturers don't bond the neutral and ground. One big reason seems to be that theses generators (yes our smaller ones are included) are sometimes connected to a home, RV, boat, etc, service panel. Our home's service panel, an RV parks power pedestal, a shore pedestal, etc. have the neutral and ground bond already in place. In these cases, the user doesn't want to connect a generator that already has a neutral/ground bond as it would go against code. Therefore, a huge reason for our floating neutral gen set .................. and a floating neutral gen set does offer some other safety advantages, but also some disadvantages when one digs deeper!

3) I'm no expert at all, but the link I've included at the end and its' MANY comments will shed a lot of light on this subject.

4) Some folks indicate it's dangerous or could harm the inverter generator by bonding. However, if a manufacturer provides a gen set that CAN be connected to a service panel or power pedestal that is already bonded, then it must be safe and harmless. Because, as I mentioned in an earlier post: "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 ............ that's if the generator is indeed connected to that panel"

This thread has helped me learn so much more! And by the way, from my research, it does appear there are many who run their gen sets in parallel and also successfully feed a service panel. That was if the two sets were made to run in parallel and some special OR cautious wiring conditions must be adhered to when connecting a 120 volt ONLY gen set to a service panel.

http://noshockzone.org/generator-ground-neutral-bonding/
 
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