manual transfer switch tripping generator breaker

[Jamesco]

Aren't there portable generators out there with a floating neutral? Wouldn't they be unsafe for portable use? If the generator had a bonded neutral but no gfci protection the breaker on the gen wouldn't trip correct? It's the gfi that sensing the ground loop issue...

Don't know.

But the one you are dealing with is.

I am still waiting for someone to respond to my suggestion that you do not connect the EGC from the generator to the EGC of the grounding system of the electrical service of the house. (Leaving the neut bonded to the frame of the portable generator)

Just curious, where is the portable generator located when it will be used connected to the MTS?

 

[rlundsrud]

I might suggest temporarily disconnecting the neutral bond on the generator to see if the gfci holds. I'm certain it will but at least you would know that is the issue. I would think if you put a label on the generator that stated the neutral was floating you would be ok leaving it that way. You would also want to explain this to the owner so he understands what that means. Otherwise as previously stated you would need a 3 pole disconnect.

 

[Jamesco]

Pretty sure you won't find a portable generator that floats the neut with GFCI protection.

The reason the neut should be bonded to the portable generator frame is provide a ground fault circuit path for the ungrounded conductor/s, in the event of a ground fault event for the GF current to return to the source. Whether the fault occurs at the generator or a ground fault event is from something that is plugged into a generator outlet.
In the world of a Grounded Power System portable generator, Its' ground reference is the metal frame of the generator.

As for GFCI protection someone mentioned there are instances where there is not a difference of potential from an ungrounded conductor, of the generator, to earth. That is true. But if a 3 wire cord and grounding type plug is connected to the generator if a hot to chassis ground fault occurs it will trip the breaker and or the GFCI, or both, depending on how much current will be flowing back on the EGC to the bonded neut/source.

I already know what someone is thinking already. But what if the EGC path is open somewhere. The metal parts of the portable tool, or what ever it is, will be Hot, energized, but unless a ground path is provided back to the bonded neut/frame of the generator no one will be the wiser.
Of course the first thing that comes to mind if the tool is plugged directly into the generator and the person using the ground faulted tool can touched the generator while holding the tool at the same time his body will become the ground fault circuit path. The GFCI, if working properly, should trip open when it senses 5ma to 6ma max of current flow.

Here is another real world situation why the neut should be bonded as well the generator should provide GFCI protection.

How many times have you guys seen form carpenters on a jobsite using a portable generator to power a worm gear portable circular saw? They may or may not be using a drop cord to connect the saw to an outlet on the generator. How many times have you seen the generator sitting on the ground? Maybe even sitting on mud from the light rain the night before? Is the bonded neut of the Generator Connected to earth?

 

[kwired]

Pretty sure you won't find a portable generator that floats the neut with GFCI protection.

The reason the neut should be bonded to the portable generator frame is provide a ground fault circuit path for the ungrounded conductor/s, in the event of a ground fault event for the GF current to return to the source. Whether the fault occurs at the generator or a ground fault event is from something that is plugged into a generator outlet.
In the world of a Grounded Power System portable generator, Its' ground reference is the metal frame of the generator.

As for GFCI protection someone mentioned there are instances where there is not a difference of potential from an ungrounded conductor, of the generator, to earth. That is true. But if a 3 wire cord and grounding type plug is connected to the generator if a hot to chassis ground fault occurs it will trip the breaker and or the GFCI, or both, depending on how much current will be flowing back on the EGC to the bonded neut/source.

I already know what someone is thinking already. But what if the EGC path is open somewhere. The metal parts of the portable tool, or what ever it is, will be Hot, energized, but unless a ground path is provided back to the bonded neut/frame of the generator no one will be the wiser.
Of course the first thing that comes to mind if the tool is plugged directly into the generator and the person using the ground faulted tool can touched the generator while holding the tool at the same time his body will become the ground fault circuit path. The GFCI, if working properly, should trip open when it senses 5ma to 6ma max of current flow.

Here is another real world situation why the neut should be bonded as well the generator should provide GFCI protection.

How many times have you guys seen form carpenters on a jobsite using a portable generator to power a worm gear portable circular saw? They may or may not be using a drop cord to connect the saw to an outlet on the generator. How many times have you seen the generator sitting on the ground? Maybe even sitting on mud from the light rain the night before? Is the bonded neut of the Generator Connected to earth?

There are many out there. GFCI still protects people using them from shock.

Big difference between a utility supplied service that has a MGN in it's distribution system and a local source that only has local grounding electrodes. You simply can't "unground" that MGN, but you can have an ungrounded (isolated) separately derived system. If you failed to connect a grounding electrode at the service - you still have a pretty large MGN network of electrodes and a pretty good ground reference.

With an on site source like a portable generator - it has no reference to anything, except it's own frame if the neutral is bonded to that frame. The fact it is isolated however means there is no potential to anything else. So first time you get a fault to "ground" (does not matter what conductor is faulted) all you really end up with is a grounded system, though not intentional. It is a second fault that causes potential shock hazards, but a GFCI will respond to the second fault, because there is now a path for unintended current to flow. Before the second fault there is no paths back to the source so no stray currents will flow.

 

[Jamesco]

I might suggest temporarily disconnecting the neutral bond on the generator to see if the gfci holds. I'm certain it will but at least you would know that is the issue. I would think if you put a label on the generator that stated the neutral was floating you would be ok leaving it that way. You would also want to explain this to the owner so he understands what that means. Otherwise as previously stated you would need a 3 pole disconnect.

I would think if you put a label on the generator that stated the neutral was floating you would be ok leaving it that way. You would also want to explain this to the owner so he understands what that means.

JMHO, a bad idea.

To a layman what are talking about, the neutral is floating?
Hey, it has GFCI protection right? Why should I be concerned if the neutral is floating, what ever that means.

What if the neighbor next door borrows the generator? Or the owner of the generator loans the generator to a relative or friend?


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[Jamesco]

There are many out there. GFCI still protects people using them from shock.

Big difference between a utility supplied service that has a MGN in it's distribution system and a local source that only has local grounding electrodes. You simply can't "unground" that MGN, but you can have an ungrounded (isolated) separately derived system. If you failed to connect a grounding electrode at the service - you still have a pretty large MGN network of electrodes and a pretty good ground reference.

With an on site source like a portable generator - it has no reference to anything, except it's own frame if the neutral is bonded to that frame. The fact it is isolated however means there is no potential to anything else. So first time you get a fault to "ground" (does not matter what conductor is faulted) all you really end up with is a grounded system, though not intentional. It is a second fault that causes potential shock hazards, but a GFCI will respond to the second fault, because there is now a path for unintended current to flow. Before the second fault there is no paths back to the source so no stray currents will flow.

There are many out there. GFCI still protects people using them from shock.

What, many out there? Portable generators where the neutral is left floating with GFCI protection?

 

[ActionDave]

What, many out there? Portable generators where the neutral is left floating with GFCI protection?

Lots of them are out there. At one time I would venture to say most were floating neutral. There has been a change in the UL listing maybe five years ago that you had to have a bonded neutral. There is no requirement that generators have to be UL listed though either.

 

[Jamesco]

Lots of them are out there. At one time I would venture to say most were floating neutral. There has been a change in the UL listing maybe five years ago that you had to have a bonded neutral. There is no requirement that generators have to be UL listed though either.

Just to be clear, portable generators where the neutral is left floating, the generator has GFCI protection? Is that what you are saying?

 

[kwired]

Just to be clear, portable generators where the neutral is left floating, the generator has GFCI protection? Is that what you are saying?

They can. On first ground fault there is no fault current - so they don't trip, but with no fault current there is no shock hazard either. Second ground fault the GFCI can sense current flowing outside intended path and can trip.

 

[Jamesco]

They can. On first ground fault there is no fault current - so they don't trip, but with no fault current there is no shock hazard either. Second ground fault the GFCI can sense current flowing outside intended path and can trip.

And the first ground fault event made that ungrounded conductor now the grounded conductor. Agree? It doesn't matter, the now grounded conductor is connected to the intended ungrounded terminal/contact on the receptacle. Reversed polarity at the 125V receptacle is not a problem, right? (Forget any electrical safety code.) Can you think any circumstances where that could pose an electrical hazard to a person?

For this discussion the ground faulted conductor is one of outer leads of the 240V winding.

Foot note:
https://www.schneider-electric.us/en/faqs/FA177591/


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[kwired]

And the first ground fault event made that ungrounded conductor now the grounded conductor. Agree? It doesn't matter, the now grounded conductor is connected to the intended ungrounded terminal/contact on the receptacle. Reversed polarity at the 125V receptacle is not a problem, right? (Forget any electrical safety code.) Can you think any circumstances where that could pose an electrical hazard to a person?

For this discussion the ground faulted conductor is one of outer leads of the 240V winding.

Foot note:
https://www.schneider-electric.us/en/faqs/FA177591/


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It is an ungrounded system. There is no "hot" conductor when it comes to polarity issues at the receptacle.

Actually is quite safer then a grounded system in many ways, if done correctly.

We have (you and myself) touched this topic in a couple recent threads and a I don't recall what I said in which thread, but the fact you don't have a utility supplied MGN means there is no huge grounding electrode network. That said, once you connect that generator to a premises wiring system that is also connected to the utility grid - you now have a huge electrode network even if you don't supply your own local electrode. If you have a bond at the generator and at the premises wiring and no switching of neutral in the transfer switch - you already have at least one parallel path for neutral current to flow. Those stray neutral currents are what cause unexpected rises in voltage on objects you don't expect to see such voltages. You don't have those stray currents with an ungrounded generator, until you have more then one fault.

 

[Jamesco]

It is an ungrounded system. There is no "hot" conductor when it comes to polarity issues at the receptacle.

Actually is quite safer then a grounded system in many ways, if done correctly.

We have (you and myself) touched this topic in a couple recent threads and a I don't recall what I said in which thread, but the fact you don't have a utility supplied MGN means there is no huge grounding electrode network. That said, once you connect that generator to a premises wiring system that is also connected to the utility grid - you now have a huge electrode network even if you don't supply your own local electrode. If you have a bond at the generator and at the premises wiring and no switching of neutral in the transfer switch - you already have at least one parallel path for neutral current to flow. Those stray neutral currents are what cause unexpected rises in voltage on objects you don't expect to see such voltages. You don't have those stray currents with an ungrounded generator, until you have more then one fault.

It is an ungrounded system. There is no "hot" conductor when it comes to polarity issues at the receptacle.

WAS....
And for what's worth I am quite familiar Isolated Power Systems.

Actually is quite safer then a grounded system in many ways, if done correctly.

Key words, "if done correctly".

Correctly? When some type of Line Isolation Monitor (LIM) is used that alerts the user there is a ground fault. At the very least an audible warning alarm. Also worth noting Isolated Power Systems should always be under the direct supervision of qualified personnel.


In this case the Isolated Power System does not have an LIM to warn the user. The ground faulted conductor, no longer an ungrounded conductor, just made it a Grounded power system. Does the user know that?

Beats me why you are continuing to beat this dead horse. A GFCI should never be installed on an Isolated power System, PERIOD!
Please look and find any UL Listed portable generator, that is wired as an Isolated Power System, that has factory installed GFCI protection. Please.

The only reason I am still posting on this thread is so some guy out there that bought a portable generator and Manual Transfer Switch from a box store is looking for the reason his generator keeps tripping the GFCI on the generator. How did he find this site? Just by using a search engine, like google, on his home computer and asking a question.
Hey them guys on the Mike Holt's electrical forum site are licensed electricians.

Just curious, what do you think the OP will end up doing to solve his problem? Will he lift the neutral on the portable generator? Is that what you are advising him to do? Or will he rip out the MTS he bought and installed, (eat the cost of his lost labor, and the cost of the MTS), and try to find one with a switched neutral?


I'll leave you with this again.

GFCI devices should never be connected to an Isolated Power System. GFCIs will not operate properly and can result in unwanted ground connection in the Isolated Power System.

https://www.schneider-electric.us/en/faqs/FA177591/

In this thread I would be willing to bet the portable generator is Listed by an NRTL, probably UL, among others. The portable generator was designed and manufactured as a Grounded Power System. Its' intended use is for use as Grounded Power System.

Please keep in mind, only guessing on my part, the only time the portable generator will be used for the purposes of this thread, is in the event of a Utility Power Outage. Just guessing on my part, when not in use the portable generator will be stored somewhere else. Also remember this is a cord and plug connected portable generator.



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[kwired]

WAS....
And for what's worth I am quite familiar Isolated Power Systems.


Key words, "if done correctly".

Correctly? When some type of Line Isolation Monitor (LIM) is used that alerts the user there is a ground fault. At the very least an audible warning alarm. Also worth noting Isolated Power Systems should always be under the direct supervision of qualified personnel.


In this case the Isolated Power System does not have an LIM to warn the user. The ground faulted conductor, no longer an ungrounded conductor, just made it a Grounded power system. Does the user know that?

Beats me why you are continuing to beat this dead horse. A GFCI should never be installed on an Isolated power System, PERIOD!
Please look and find any UL Listed portable generator, that is wired as an Isolated Power System, that has factory installed GFCI protection. Please.

The only reason I am still posting on this thread is so some guy out there that bought a portable generator and Manual Transfer Switch from a box store is looking for the reason his generator keeps tripping the GFCI on the generator. How did he find this site? Just by using a search engine, like google, on his home computer and asking a question.
Hey them guys on the Mike Holt's electrical forum site are licensed electricians.

Just curious, what do you think the OP will end up doing to solve his problem? Will he lift the neutral on the portable generator? Is that what you are advising him to do? Or will he rip out the MTS he bought and installed, (eat the cost of his lost labor, and the cost of the MTS), and try to find one with a switched neutral?


I'll leave you with this again.

https://www.schneider-electric.us/en/faqs/FA177591/

In this thread I would be willing to bet the portable generator is Listed by an NRTL, probably UL, among others. The portable generator was designed and manufactured as a Grounded Power System. Its' intended use is for use as Grounded Power System.

Please keep in mind, only guessing on my part, the only time the portable generator will be used for the purposes of this thread, is in the event of a Utility Power Outage. Just guessing on my part, when not in use the portable generator will be stored somewhere else. Also remember this is a cord and plug connected portable generator.



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I can only tell you that it was common to have portable generator with no neutral to frame bonding.

Has already been mentioned that more recent listing requirements want the neutral bonded. Also mentioned that listing of generators is not required. Plus you have a mixed bag of old and new out there.

I have a 8000 watt portable that has 2- 5-15 GFCi receptacles and a L14-30 receptacle. L14-30 not GFCI protected, neutral is isolated from frame. I do have an a pigtail to connect it to my premises wiring via transfer switch. Both neutral and EGC are connected and bonded at the service equipment when connected to premises wiring. It is a grounded system when plugged into my premises wiring. The green wire in the power cord does connect the generator frame to the EGC so a ground fault in the generator itself will still fault to an EGC.

When I take it to a job and just run power tools off the 5-15's it is an ungrounded system. I don't drive a ground rod, even if I did I'd still need to tie neutral to generator frame, other wise all I am doing is referencing the frame to the ground rod. I feel I am in no danger should the black wire in a power cord fault to tool or other conductive object, there is no potential to those other objects until that black wire faults to them.

I'm telling you to go around and check as many portable generators as you can especially if they are more then about 5-8 years old. Don't even need to start them up, just connect an ohmmeter or continuity tester from the neutral to the frame/EGC terminal. If you have no continuity it is a floating neutral. I bet you find more then you expect that are floating if over 5-8 years old.

This is not a new topic of discussion for this site either. I think there are many that will agree with what I said.

What is owner going to do if it is or is not bonded when it should be the other way around? The basic rules haven't really changed, if a "separately derived system" you need to switch the neutral with transfer equipment, if not a separately derived system you don't need to switch the neutral. Non electricians as well as some that claim to be electricians have never understood that. Putting GFCI's on the 120/240 volt receptacles is going to either get more electricians involved because they don't hold or will force the untrained to remove/disable the GFCI's.

 

[LarryFine]

To repeat myself, unless I'm mistaken, the type of transfer panel in the OP is the type with individual 1P2T switches, and the circuit neutrals remain on the original panel's neutral bus, so no neutral switching is available.

 

[George Stolz]

I am still waiting for someone to respond to my suggestion that you do not connect the EGC from the generator to the EGC of the grounding system of the electrical service of the house. (Leaving the neut bonded to the frame of the portable generator)

I already did: :blink:

I hate to break up the "angels on the head of a pin" discussion, but in lieu of wondering, cussing, discussing and never getting anywhere, can we get back to the roots of this forum and crack the cover on an NEC?

445.20 spells out the rules for the generator GFCI protection, I don't see where a 30A outlet requires it. If the generator came that way, it would be worth looking into just removing the code-violating jumper (or the whole generator.)

250 requires connection of EGCs all over the place, exhaustively, leaving one out is nuts.

250.24(A)(5) forbids a N-G connection on the load side of a service.

100 makes it clear without switching the neutral, this is not a separately derived system, and the bonding jumper in the generator is non-compliant.

702.7(C) requires a sign clarifying to the end user what kind of generator to connect to the inlet (floating in this case.)

250.34(A) gives additional requirements.

What's left?

 

[Jamesco]

I can only tell you that it was common to have portable generator with no neutral to frame bonding.

Has already been mentioned that more recent listing requirements want the neutral bonded. Also mentioned that listing of generators is not required. Plus you have a mixed bag of old and new out there.

I have a 8000 watt portable that has 2- 5-15 GFCi receptacles and a L14-30 receptacle. L14-30 not GFCI protected, neutral is isolated from frame. I do have an a pigtail to connect it to my premises wiring via transfer switch. Both neutral and EGC are connected and bonded at the service equipment when connected to premises wiring. It is a grounded system when plugged into my premises wiring. The green wire in the power cord does connect the generator frame to the EGC so a ground fault in the generator itself will still fault to an EGC.
When I take it to a job and just run power tools off the 5-15's it is an ungrounded system. I don't drive a ground rod, even if I did I'd still need to tie neutral to generator frame, other wise all I am doing is referencing the frame to the ground rod. I feel I am in no danger should the black wire in a power cord fault to tool or other conductive object, there is no potential to those other objects until that black wire faults to them.

I'm telling you to go around and check as many portable generators as you can especially if they are more then about 5-8 years old. Don't even need to start them up, just connect an ohmmeter or continuity tester from the neutral to the frame/EGC terminal. If you have no continuity it is a floating neutral. I bet you find more then you expect that are floating if over 5-8 years old.

This is not a new topic of discussion for this site either. I think there are many that will agree with what I said.

What is owner going to do if it is or is not bonded when it should be the other way around? The basic rules haven't really changed, if a "separately derived system" you need to switch the neutral with transfer equipment, if not a separately derived system you don't need to switch the neutral. Non electricians as well as some that claim to be electricians have never understood that. Putting GFCI's on the 120/240 volt receptacles is going to either get more electricians involved because they don't hold or will force the untrained to remove/disable the GFCI's.

>>>>>>>>

I can only tell you that it was common to have portable generator with no neutral to frame bonding.

Correct you are! I was surprised to see just how many are being sold at big box stores. Many without GFCI protection on the 125V 15 and 20 outlets and a few with GFCI protection. Home Depot seem to carry the most portable generators with floating neutrals, in my area. I did notice the ones at HD, as well as other Box Stores, stated on the front panel "Floating Neutral". None of the floating neut portable generators were approved, listed, by UL or any NRTL.. None that I looked at.....

Like you said in an earlier post, and I agree, there is not any consumer protection law that says a consumer product must be safety Listed.

Here is a good example.
http://www.mapleshaderecords.com/audioproducts/powercord_prev.php

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Has already been mentioned that more recent listing requirements want the neutral bonded. Also mentioned that listing of generators is not required. Plus you have a mixed bag of old and new out there.

Agree.

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I have a 8000 watt portable that has 2- 5-15 GFCi receptacles and a L14-30 receptacle. L14-30 not GFCI protected, neutral is isolated from frame. I do have an a pigtail to connect it to my premises wiring via transfer switch. Both neutral and EGC are connected and bonded at the service equipment when connected to premises wiring. It is a grounded system when plugged into my premises wiring. The green wire in the power cord does connect the generator frame to the EGC so a ground fault in the generator itself will still fault to an EGC.

When I take it to a job and just run power tools off the 5-15's it is an ungrounded system. I don't drive a ground rod, even if I did I'd still need to tie neutral to generator frame, other wise all I am doing is referencing the frame to the ground rod. I feel I am in no danger should the black wire in a power cord fault to tool or other conductive object, there is no potential to those other objects until that black wire faults to them.

Doing a search for OSHA requirements for use of portable generators on job sites, I ran across this White Paper. Note the date of the paper is 2005 and may not reflect current day OSHA requirements.
http://www.arrl.org/files/file/Tech... and OSHA Construction Standards 3-05 (1).pdf
Your thoughts please?
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I'm telling you to go around and check as many portable generators as you can especially if they are more then about 5-8 years old. Don't even need to start them up, just connect an ohmmeter or continuity tester from the neutral to the frame/EGC terminal. If you have no continuity it is a floating neutral. I bet you find more then you expect that are floating if over 5-8 years old.

Agree, addressed above.

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What is owner going to do if it is or is not bonded when it should be the other way around? The basic rules haven't really changed, if a "separately derived system" you need to switch the neutral with transfer equipment, if not a separately derived system you don't need to switch the neutral. Non electricians as well as some that claim to be electricians have never understood that. Putting GFCI's on the 120/240 volt receptacles is going to either get more electricians involved because they don't hold or will force the untrained to remove/disable the GFCI's.

Don't blame the owner if he already owned the portable generator before hiring the electrician. Blame the electrician. He should have bought the correct MTS.

As for this thread the OP never really stated if the property owner already owned the generator in question before calling him to install the MTS. I only assumed that to be the case. The OP, electrician, should have first checked the portable generator to see if the neut was bonded or floating before buying the MTS. He did not though. (Keep in mind the portable generator was designed and manufactured with the neutral bonded to the frame. Is it UL Listed? We don't know.) The OP, electrician, should have bought an MTS that switched the neutral. I stated my reasons against floating the neutral on the portable generator. If you read the OSHA link I provided above you read the OSHA instructor stated the same concerns as I have when the portable generator is used, as potable generator, and has a 120/240 gen head. Can the OP guarantee the owner of the portable generator will not use the generator for tasks other than using it as a back up power system for his house? Can the OP guarantee the owner of the generator will not loan out the portable generator?


Worth noting if the bonded neut portable generator in question had not had GFCI protection this thread would never had been posted. The OP would have started the generator, plugged in the cord and plug that feeds power to the MTS, checked line to line and line to neut voltages, transferred loads to generator, and checked the load current. I doubt he would have checked the ECG for load current on the EGC. He would have closed everything up, cleaned up his mess, showed the property owner how to properly use the gen back up system, handed the customer the bill, collect his money, got in his van and left, and never looked back.


I called Leviton tech Support last week and asked if the Leviton 125V 15 and 20 amp GFCI duplex receptacles are rated for a 240V as well as a 240V bolted ground fault. He said yes, and UL approved.


Also note new for 2017 NEC 445.20(A)&(B)

You thoughts? Understanding?


How does that apply to the concerns of OSHA as stated in the link I provided relating to 120/240V gen heads?


One other question, if I may. When a portable generator is connected to a premises approved TS, does NEC require the portable generator shall be approved? It's not a load cord and plug connected piece of equipment.



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[Jamesco]

Correction:

Originally Posted by kwired
I can only tell you that it was common to have portable generator with no neutral to frame bonding.

Correct you are! I was surprised to see just how many are being sold at big box stores. Many without GFCI protection on the 125V 15 and 20 outlets and a few with GFCI protection. Home Depot seem to carry the most portable generators with floating neutrals, in my area. I did notice the ones at HD, as well as other Box Stores, stated on the front panel "Floating Neutral". None of the floating neut portable generators were approved, listed, by UL or any NRTL.. None that I looked at.....

Should read:

I was surprised to see just how many are being sold at big box stores. Many without GFCI protection on the 125V 15 amp and 20 amp outlets and a few with GFCI protection.


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[Reliance]

No UL standard for generators

No UL standard for generators

There is nothing that requires a portable generator to be bonded or floating unless the generator is being used at an OSHA jobsite. UL has pushed UL 2201 for a long time as a private industry standard where rules for portables were included but it was never approved as an ANSI standard. Just a few years ago the Portable Generators Manufacturers Association (PGMA) wrote G300 and was voted in as the ANSI standard, the first for portable generators. G300 does not require a generator to be bonded or floating, although it may require the labeling of one or the other. To date no generators are "listed" to this standard yet, but no generators are listed to ANY standard, UL 2201 or otherwise (as far as I know).

The 2017 NEC in Article 445 does require GFCI protection on the 15 and 20 amp 125 volt outlets, or to make them unavailable when the 125/250 VAC outlet is in use. But it does not address the neutral relation to ground in the generator.

A lot of the generator manufacturers will support removing the bond wire between neutral and frame, with instructions to cover up the "neutral bonded to frame" statement on the receptacle panel. Many will agree that it's not "unsafe" to use a floating neutral generator as a portable power source - not connecting it to a premises wiring system. If there is a fault condition the ground wire in the cord cannot act as a return path but alternatively if the generator was bonded and there was a fault the GFCI's are expected to trip. Of course most portables that are bonded neutral do not have GFCI protection on the 125/250 VAC outlet because it's not required, but a few models have full GFCI protection - not many at all.

There isn't a rule likely because nobody can agree what's always best, portable generator applications have such a wide variety of conditions from job sites to back yards to camping to back-up power with transfer switches, and as was mentioned in this thread there are advantages and disadvantages of bonding or floating the neutral. If we bond the neutral we are setting ourselves up to create ground faults and relying on the GFCI sensors to trip before we get shocked. If we float the neutral we are ridding ourselves of potential ground fault shock hazards but GFCI's will not work in the same way they are expected to work in a bonded system. Whether that's good or bad is not for me to decide, but if I had a generator personally I would want it to be floating so that if there was a ground fault in a cord or tool, I couldn't complete a circuit by getting between ground and hot.

 

[GerryB]

Where is GFCI protection required for this installation?

Edit to add before bed: if it is required, then removing the bonding jumper in the generator (relying on the one in the service) is the compliant fix I see.

This must be a new generator that conforms with the 2017 code that requires (I know I read this) GFI protection for 30 and 50 amp devices. (Not sure if it is all cases) Most portable generators I've seen only have the 110 outlets GFI. Good reason to use an interlock switch instead of those outdated 6 and 10 ckt panels.

 

[meandenno1]

But why was the circuit breaker tripping

But why was the circuit breaker tripping

The original thread was because the GFI on the generator was tripping, assuming the generator has GFI protection on the 30amp TL output...OK feeding a main breaker type load panel and a generator load panel that does not separate the grounds and neutrals the GFI senses the current flow through the bonding jumper ground loop thus created and trips. But why was the circuit breaker tripping? That happens when the generator connection cord or the generator inlet is wired improperly or an undiagnosed short down line. As I read it the generator has to be wired as a separately derived system if the ground and neutral are bonded in the standby power system. The short is a separate issue.