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So on systems where neutral is not disconnected from grid, interconnect switch, you are suppose to not have the ground bonded to the neutral at the generator.
Why do I care? If my neutral and ground wire are same gauge, length, and terminations. I just don’t see it as a problem.
 

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So on systems where neutral is not disconnected from grid, interconnect switch, you are suppose to not have the ground bonded to the neutral at the generator.
Correct. That is known as Not a Separately Derived System. It looks something like this. Notice that the N-G bond at the generator is not there. The N-G system bond is at the far left.
Rectangle Font Parallel Engineering Diagram

Why do I care? If my neutral and ground wire are same gauge, length, and terminations. I just don’t see it as a problem.
The codes state that only one N-G bond be made in an electrical system. Its all about safety. The codes have been developed over many decades and, unfortunately, revisions made after someone has died or been severely injured due to the way a system was wired. Running the system with the N-G bond in two places puts the wires in parallel. The neutral and the ground will share the current flow. This is known as objectionable current.

We can't tell you what to do...we can only point to the proper way by code.
 

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@tabora Well, I think I have changed my mind about disconnecting the rectifier. I think the gen should still start and run with it disconnected because the battery would supply the power to fuel solenoid and other electronics. Right?
Maybe? Easy to try it if you have the generator as @DL41 does. I'd need to spend some time deciphering the function of the Dual Fuel module SM1-SM4 switches as shown in the diagram's switching chart.
 

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...
Why do I care? If my neutral and ground wire are same gauge, length, and terminations. I just don’t see it as a problem.
you are allowed to have parallel conductors in certain circumstances (greater then 1/0 wire), with same gage, length and terminations... i just can't get excited about it, and I'm an engineer...

there are some failure modes where it would be better and some where not...
 

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you are allowed to have parallel conductors in certain circumstances (greater then 1/0 wire)
Yup, but it doesn't allow for neutrals and ground conductors to be paralleled to each other. You still need a minimum of 4 wires for a 120/240V system. The ECG falls under a slightly different rule [250.122(F)(1)] when it comes to paralleling.

And that would be a really big generator to require 1/0 wire in parallel! I would hate having to load that up if someone wanted to borrow it. :)
 

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Correct. That is known as Not a Separately Derived System. It looks something like this. Notice that the N-G bond at the generator is not there. The N-G system bond is at the far left.
View attachment 12041

The codes state that only one N-G bond be made in an electrical system. It all about safety. The codes have been developed over many decades and, unfortunately, revisions made after someone has died or been severely injured due to the way a system was wired. Running the system with the N-G bond in two places puts the wires in parallel. The neutral and the ground will share the current flow. This is known as objectionable current.

We can't tell you what to do...we can only point to the proper way by code.
I’ve watched every video i could find on this topic and still can’t sort this in my mind.

I have ( like many many others ) a portable generator that has a bonded neutral. I run a 4 conductor cable (H,H,N,G ) to a gen inlet box that is connected to a 50 Amp breaker in my panel H,H ) with the neutral and grounds tied to the panel. I manage the power between mains and generator with a mechanical interlock.
There are no sub panels in the house so my main panel ( service panel ) has the ground and neutral bonded. I get the point where a sub panel needs to be unbonded else ground fault or imbalanced currents will travel back from the sub panel to the service panel on both neutral and ground and create all kinds of potential voltages at any point on the various loads on the sub panel and the main panel.
Q1. Is this the same risk when running a generator? Any loads in my service panel that may become ground fault or imbalance drill have the bonded NG at the panel to clear the fault OR is the concern that there could be potential created between the panel and the gen set?
Q2. Does code differentiate between fixed power supplies ( hard wired generator or service wires compared to a portable power ).

Another thing I’m struggling to understand is the difference between a manual transfer switch that can unbond the neutral from the generator vs a GFI transfer switch which apparently is bein GB used by people with a gen set that has GFCI protection on all of the plugs. My gen is not GFCI protected so when I use my generator I don’t trip any breakers.
So I guess my question is. If there is a manual transfer switch that can unbond the neutral from the generator ….is that the same as simply NOT connecting the neutral wire from my generator to my panel?
Appreciate any thoughts
Cheers.
Mac.
 

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I’ve watched every video i could find on this topic and still can’t sort this in my mind.

I have ( like many many others ) a portable generator that has a bonded neutral. I run a 4 conductor cable (H,H,N,G ) to a gen inlet box that is connected to a 50 Amp breaker in my panel H,H ) with the neutral and grounds tied to the panel. I manage the power between mains and generator with a mechanical interlock.
There are no sub panels in the house so my main panel ( service panel ) has the ground and neutral bonded. I get the point where a sub panel needs to be unbonded else ground fault or imbalanced currents will travel back from the sub panel to the service panel on both neutral and ground and create all kinds of potential voltages at any point on the various loads on the sub panel and the main panel.
Q1. Is this the same risk when running a generator? Any loads in my service panel that may become ground fault or imbalance drill have the bonded NG at the panel to clear the fault OR is the concern that there could be potential created between the panel and the gen set?
Q2. Does code differentiate between fixed power supplies ( hard wired generator or service wires compared to a portable power ).

Another thing I’m struggling to understand is the difference between a manual transfer switch that can unbond the neutral from the generator vs a GFI transfer switch which apparently is bein GB used by people with a gen set that has GFCI protection on all of the plugs. My gen is not GFCI protected so when I use my generator I don’t trip any breakers.
So I guess my question is. If there is a manual transfer switch that can unbond the neutral from the generator ….is that the same as simply NOT connecting the neutral wire from my generator to my panel?
Appreciate any thoughts
Cheers.
Mac.
Forgot to add.
or does a switched neutral transfer switch use a relay to bind the neutral when on mains then open the relay when on gen power? And is it the same as a GFI transfer switch?
thanks.
 

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I run a 4 conductor cable (H,H,N,G ) to a gen inlet box that is connected to a 50 Amp breaker in my panel H,H ) with the neutral and grounds tied to the panel. I manage the power between mains and generator with a mechanical interlock.
That is a Not Separately Derived System because you are not switching the neutral. You need to break the N-G bond at the gen though to get it right. Otherwise, you are putting the neutral in parallel with the EGC and causing current flow on both wires.

Q1. Is this the same risk when running a generator? Any loads in my service panel that may become ground fault or imbalance drill have the bonded NG at the panel to clear the fault OR is the concern that there could be potential created between the panel and the gen set?
A subpanel is similar to wiring up a gen in that you do not have a N-G bond (and they often require a ground rod at the subpanel). You shouldn't have a potential between the panel and gen as long as the EGC is in place and not switched.

Q2. Does code differentiate between fixed power supplies ( hard wired generator or service wires compared to a portable power ).
A hard wired gen is similar to a portable gen as far as wiring goes...just a few less plugs and whatnot in place with hard wiring.

If there is a manual transfer switch that can unbond the neutral from the generator ….is that the same as simply NOT connecting the neutral wire from my generator to my panel?
You can have a Seperately Derived System that switches the neutral along with the two hots...if that is what you are asking. In a Separately Derived System the N-G bond at the gen stays in place and the gen has a ground rod. Also, the EGC is not switched along with the H-H-N.

^^^ At least that is the way I understand it! :)
 

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Forgot to add.
or does a switched neutral transfer switch use a relay to bind the neutral when on mains then open the relay when on gen power? And is it the same as a GFI transfer switch?
For those that don't (or can't) break the N-G bond at the gen, the Seperately Derived System is the best way to go, IMHO. A three-pole switch is needed because the neutral is switched. Those are used as GFCI transfer switches also. See this as an example...
 

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For those that don't (or can't) break the N-G bond at the gen, the Seperately Derived System is the best way to go, IMHO. A three-pole switch is needed because the neutral is switched. Those are used as GFCI transfer switches also. See this as an example...
I don’t think this is code but interesting analysis.
 

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And another thought about that...

His insurance company may deny his claim should he have a fire even if it had nothing to do with the gen-house wiring. They always look for a way out of paying a claim.
 

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And another thought about that...

His insurance company may deny his claim should he have a fire even if it had nothing to do with the gen-house wiring. They always look for a way out of paying a claim.
I have 2 generators.
13000 kw propane / natural gas Mecc Alte alternator. I’ve sent Mecc Alte an email to see if they can provide the details for removing the GN bond.

I also have a pulsar 12kw tri fuel ( converted ) generator. Similarly - I’ve reached out to them to see if they can provide details if removing the GN bond.
Given the option I’m going to see if I can get a floating neutral that will sort all of this bonded neutral in my panel.
Will update if I hear back from either of them.
Regards

mac.
 

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I have 2 generators.
13000 kw propane / natural gas Mecc Alte alternator. I’ve sent Mecc Alte an email to see if they can provide the details for removing the GN bond.

I also have a pulsar 12kw tri fuel ( converted ) generator. Similarly - I’ve reached out to them to see if they can provide details if removing the GN bond.
Given the option I’m going to see if I can get a floating neutral that will sort all of this bonded neutral in my panel.
Will update if I hear back from either of them.
Regards

mac.
Northstar couldn’t provide
I have 2 generators.
13000 kw propane / natural gas Mecc Alte alternator. I’ve sent Mecc Alte an email to see if they can provide the details for removing the GN bond.

I also have a pulsar 12kw tri fuel ( converted ) generator. Similarly - I’ve reached out to them to see if they can provide details if removing the GN bond.
Given the option I’m going to see if I can get a floating neutral that will sort all of this bonded neutral in my panel.
Will update if I hear back from either of them.
Regards

mac.
so. Northstar couldn’t provide any information on de bonding GN. Pulsar replied back with pics and confirmed no issues with removing the bond.
Product Font Gas Internet meme Cable
 

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The Pulsar looks like a typical bonding wire. Check for continuity between ground and neutral before and after disconnecting the bond wire. Gen should not be running of course.

Look on the Northstar for a similar type bonding wire. Sometimes they are on the panel if not on the alternator.
 

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I’m definitely not an electrician, but I thought the same thing. So, I added the neutral ground bond wire back in, and the rectifier didn’t heat up and smoke. I removed the bond again, and it smoked and melted the rectifier. When I called Firman, both the tech and the parts guy said that is exactly what will happen because the wiring is more complex in that machine. What that all means, I don’t know. But I did test it, and re-test and have Firman confirm. If anybody has any additional insight, or can see something I screwed up on, I’d be happy for the feedback.

Attached is a picture of the jumper wire I removed and a picture of the rectifier before it melted
@DL41- Did you find a way to converting T07571 to floating neutral? Have explored further?

Thank you in Advance!
 

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On the Northstar, look here...
View attachment 12083
Again, check before and after for continuity between neutral and ground at the front panel plugs.
My Northstar is a little different. It has a Mecc Alte 14kva alternator.
I have a pic attached below.
There are 4 posts on the terminal block.
The 2 right posts connect the hots from the alternator through to the panel.

The two posts on the right are connected to 2 different neutrals from the alternator. Odd I know but there are 2 neutral wires running from the terminal block back to the alternator. Both of these terminals are tied together with a bonding strap. Each post is also bonded back to ground with 2 bond straps. Then there is 1 neutral running to the panel.

Prior to removing GN bonds I did verify that there was continuity between G and N on my 30 amp plug.
After removing both GN bond wires I confirmed that there was NOT continuity between G and N.


Neither Mecc Alte nor Northstar would provide info on removing the GN bond. Mecc Alte said to refer to the final generator builder ( Northstar ) and NorthStar said they couldn’t comment due to it being a liability for them to instruct anyone on modifying equipment.

So. General questions

I connect to my service panel with a 4 wire gen cable. It has an 8 gauge ground ( 6 gauge hot and neutral ). My service panel does have a GN bond.

Technically speaking. Even if I remove the GN bond at the generator the system still has a GN bond through the cable and service panel….Yes? I’m trying to think about any potential issues this might create. Service or safety wise.

i rarely if ever use this generator unless it’s plugged into the house. I’m assuming the house ground at the service panel should be sufficient for a system ground vs grounding at the gen itself. Appreciate some thoughts.

lastly. I appreciate that if ever running stand alone I won’t have a GN bond and from what I’ve read this is a safety risk. Makes sense to make a 120v 3 prong male plug and jump the ground to neutral and just plug it in one of the 120 outlets. Yes?
Appreciate any thoughts.
Regards
Light Hood Automotive tire Motor vehicle Rim
Kitchen utensil Electrical wiring Gesture Circuit component Audio equipment

Mac.
 

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Even if I remove the GN bond at the generator the system still has a GN bond through the cable and service panel….Yes?
Yes, the distribution panel will supply the single N-G bond for the entire system (house + gen).
I’m trying to think about any potential issues this might create. Service or safety wise.
It doesn't necessarily cause a safety issue. My new WEN GN625i came from the factory with a floating neutral. Whereas my old Champion came bonded. There isn't a standard. However, if a gen is modified from what is stated on the front panel, then a label is highly recommended so that another person using the gen down the road knows about the mod. If using the gen as a standalone unit, a N-G bonding plug can be used to quickly add the bond back to the unit.
Both of these terminals are tied together with a bonding strap. Each post is also bonded back to ground with 2 bond straps. Then there is 1 neutral running to the panel.
So, if I am understanding that correctly, you removed the 2 wires going to ground? The bonding straps are still in place between the 2 neutral posts with 1 neutral wire going to the panel.
 

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Yes, the distribution panel will supply the single N-G bond for the entire system (house + gen).

It doesn't necessarily cause a safety issue. My new WEB GN625i came from the factory with a floating neutral. Whereas my old Champion came bonded. There isn't a standard. However, if a gen is modified from what is stated on the front panel, then a label is highly recommended so that another person using the gen down the road knows about the mod. If using the gen as a standalone unit, a N-G bonding plug can be used to quickly add the bond back to the unit.

So, if I am understanding that correctly, you removed the 2 wires going to ground? The bonding straps are still in place between the 2 neutral posts with 1 neutral wire going to the panel.
I was thinking of a label as well.

Correct - Removed grounds. Left the strap between neutrals.

Hopefully good to go now.
Thanks.
 
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