Another Generator Grounding Question

[goldstar]

There are no exceptions except in the minds of those who persist in proving that it can be done and justifying it by the use of the word ?safer?

:weeping: Ouch Mike !!! That really hurts. FYI, I was never out to prove you wrong. I respect you for your knowledge and the fact that you've stuck with this in spite of any negative comments you've received. You've managed to sway some to your school of thought, but apparently not the entire country. However, what you should be doing is proving the generator manufacturer's wrong for marketing these units (and accessories that go with them) in the manner they have.

All of this is a moot point any way due to the requirement that all generators that have receptacles mounted on the frame the receptacle is to be GFCI protected and this will prevent the use of the generator as a non-SDS see 590.6(A)(3)

If that's a requirement no one has told this sales company yet http://www.electricgeneratorsdirect.com/ . (And this is only one of many I'm sure). When they start making these units with ALL receptacles being GFI protected (120 and/or 240 volt) then you will no longer have to make your argument here. That portion of the generator market will all but dry up like it has in your section of NC.

I would like to re-post my question - can I use this 17.5KW portable as a non-SDS unit in accordance with the language of UL-FTCN ? http://www.electricgeneratorsdirect.com/Generac-5735-Portable-Generator/p2685.html . If I'm of your frame of mind I already know the answer. I'd just like to hear ir from you as to what portion(s) of UL-FTCN you're in agreement with. Do you agree with the exact wording of this section or its intent ?

 

[jwelectric]

Ice and Gold,

I don?t mean to be rude although I sometimes come across that way. Please have a very Merry Christmas.

Gold, one can connect a 3000 watt generator to premises wiring as long as the generator does not supply power to the wiring system through a receptacle mounted on the frame of the generator. If a 20kw generator has devices mounted on the frame then it will be required to have the neutral bonded to the frame and thus be a SDS and installed accordingly. A generator that does not have receptacles mounted to the frame can be installed either as a SDS or a non-SDS and it is not the transfer switch that makes the unit but the bonding of the unit that mandates the type of transfer switch.

Both of you stop and think about a conductor coming from the winding of the generator to supply a receptacle on the frame of the generator. Now think about all that vibration that happens when the generator is sitting out there running. These leads go through first one hole then another so on and so forth until they reach the devices mounted on the frame.

If the frame of that generator is not bonded and that lead gets worn to the bare copper what is going to clear the fault? I load that generator on the back of my truck so I can use it to drill a hole in a 4x6 to hang a gate in my pasture. I plug the drill into the receptacle that is not worn wonder what the voltage would be on that receptacle?

From the un-shorted winding through the receptacle back through the neutral is 120 volts BUT from the other side of the winding to the frame of the generator through the EGC to the drill and it will now have whatever the two voltages would add up to be.

One thing I can say about myself is that I am not so closed minded to think that the only use of a stand-alone type of generator is to connect to my house. The two that I have has been all over this farm doing first one thing and then another. The one thing that neither of the two has ever done is be connected to my house even when we sat here for nine days with ice hanging on the trees without any utility power. I used my generators as a 590 application not a 702 application.

I suppose that this whole discussion comes down to what the definition of portable means. If we are talking about portable X-ray equipment then it is hand carried or if we are talking about TV studios it is something that is moved about such as portable stages. If we are talking about theaters then there are even portable switchgears. Cranes used to build high-rise buildings are moved after construction meaning they are portable.

I do hope and pray that I never get to the point to where I hear the phrase portable generator my mind stops at a stand-alone SDS type of generator and the belief that there is some compliant way to connect these items to my home using a cord and plug. I would venture as far to say that any generator that is not installed as a 250.35 installation would be a portable generator even if it was set by a crane or was delivered by rail.

here is a portable generator that is connected using conductors attached to the generator and not cord and plug connected



Once all that smoke clears one can easily see that a portable generator that has the receptacles mounted on the frame is to be used as a 590 application and not as a 702 application. A generator that is used as a 702 application MUST adhere to the rules outlined in Chapters and Articles of the NEC as I have so diligently posted throughout this thread.

 

[GoldDigger]

And a Merry Christmas to you and yours!
Basically we agree on what can happen at the 120V receptacle, but started off using different terminology and that led to some confusion.
I am correct that there can be at most 120V between the hot and neutral conductor and you are right that there could be 240V between hot and EGC.
Any 120V load will be destroyed by 240V hot to neutral, while some may be adversely affected or unsafe with that same voltage from hot to EGC.
And if there is a bond anywhere in the connected system, no matter what sort of wiring is used to carry the 3 (4) wires, it will short out a winding and cause the generator to shut down.

Sent from my XT1080 using Tapatalk

 

[goldstar]

I don?t mean to be rude although I sometimes come across that way. Please have a very Merry Christmas.

I don't believe you're rude at all, I'm just busting you a bit. I think your position is well taken but I just don't see the generator market changing based on your opinion here in the Forum and I never meant to insinuate that you were wrong. However, while I believe you've educated many of us here in the Forum or have brought things to our attention that many of us may not have known before, as long as a market exists whereby HO's are connecting portables to their houses, and as long as that is an accepted practice in the areas I work in I will continue to make those installations. When you convince Generac, Briggs & Stratton, Reliance and the like that they should no longer manufacture or market these products to HO's then we'll all stop.

Regards and Merry Christmas to you and your family. :thumbsup:

 

[iceworm]

Technical discussion set aside. Responding to post:

... I don?t mean to be rude although I sometimes come across that way. ...

Can't say I agree with gold. Mean to or not - you are rude.

... Both of you stop and think about a conductor coming from the winding of the generator to supply a receptacle on the frame of the generator. Now think about all that vibration that happens when the generator is sitting out there running. These leads go through first one hole then another so on and so forth until they reach the devices mounted on the frame.

If the frame of that generator is not bonded and that lead gets worn to the bare copper what is going to clear the fault? I load that generator on the back of my truck so I can use it to drill a hole in a 4x6 to hang a gate in my pasture. I plug the drill into the receptacle that is not worn wonder what the voltage would be on that receptacle?

From the un-shorted winding through the receptacle back through the neutral is 120 volts BUT from the other side of the winding to the frame of the generator through the EGC to the drill and it will now have whatever the two voltages would add up to be. .

Stopping......
Thinking...........
Okay. Glad to see you finally understand the voltage between the hot and neutral does not increase. Perhaps eventually you will see that if gen is connected to premises wiring as a non-sds, the premises main panel supplies NG bond to trip the gen main CB

... . The one thing that neither of the two has ever done is be connected to my house even when we sat here for nine days with ice hanging on the trees without any utility power. I used my generators as a 590 application not a 702 application.

Nine days of sub 32F? Icicles? I didn't know that that could happen in North Carolina. Be that as it may, it is very noble of you to put empty code compliance ahead of potentially freezing up and destroying a large portion of your home.

I got to say, I'm not that noble. At -40F, I might wait an hour - maybe 4 hours, but I will connect a cord and plug gen (non-SDS) to my house before I will let it freeze up. Even as warm as -20F I might wait 12 - 24 hours - But I'll still be ignoble (is that a word?) and connect the gen before freeze-up.

I'm still curious about your responses my curiousity questions.

ice

 

[jwelectric]

I'm still curious about your responses my curiousity questions.

ice

I did answer your curious question here

I would venture as far to say that any generator that is not installed as a 250.35 installation would be a portable generator even if it was set by a crane or was delivered by rail.

Mike -
You never answered my curiousity question:
Do you consider a skid mounted generator, off-loaded by forklift, as "portable generation"? - just curious.

 

[iceworm]

I did answer your curious question here

okay,that is one - how about the other?

icr

 

[jwelectric]

okay,that is one - how about the other?

icr

help me out a little and repeat the question, please
If it is a question comparing a mobile home, RV or a substation to that of a generator it doesn?t deserve an answer as this would be comparing oranges to lemons.

If it is a question concerning physics then the answer would be the early bird is the one who got the worm or something like that.

I have a question or two of my own but no one seems interested enough to answer any of them. In school I was told that every action has an opposite and equal reaction. If this is true is the low potenuse of a left triangle the opposite and equal to the hypotenuse of a right triangle.

 

[GoldDigger]

No. It would have to be the repotenuse.

Sent from my XT1080 using Tapatalk

 

[GoldDigger]

No. It would have to be the repotenuse.

Sent from my XT1080 using Tapatalk

Unless, of course, it is a single-phase 3-line system.

 

[iceworm]

help me out a little and repeat the question, please
If it is a question comparing a mobile home, RV or a substation to that of a generator it doesn?t deserve an answer as this would be comparing oranges to lemons.

If it is a question concerning physics then the answer would be the early bird is the one who got the worm or something like that.

I have a question or two of my own but no one seems interested enough to answer any of them. In school I was told that every action has an opposite and equal reaction. If this is true is the low potenuse of a left triangle the opposite and equal to the hypotenuse of a right triangle.

Nah - no more - you are right, time for some silly.

Although:
I would have use oranges to tangerines for comparison.
It's true I am the Worm, but I am not the early worm for a good reason

Luckily for me goldstar got the next one

Merry Christmas all.

ice

 

[jwelectric]

I was looking at the 2014 analysis of changes when I found this slide showing a portable generator being connected by a cord that I found interesting enough to post the slide.

Notice the phrase "portable generator" used in the slide



And to think that some think of potable generators as being the stand-alone type

 

[don_resqcapt19]

I was looking at the 2014 analysis of changes when I found this slide showing a portable generator being connected by a cord that I found interesting enough to post the slide.

Notice the phrase "portable generator" used in the slide



And to think that some think of potable generators as being the stand-alone type

But the actual rule really says that the portable generator can be either SDS or non-SDS.

 

[goldstar]

It's true I am the Worm, but I am not the early worm for a good reason

Luckily for me goldstar got the next one

Merry Christmas all.

ice

I don't know about eating worms but I eat a lot of crow here in the Forum. I have recipes if you're interested >

 

[goldstar]

OK, I wanted to drop out of this thread but after seeing this slide I'm starting to get confused. Let me start by re-posting UL-FTCN as it pertains to this slide:

ENGINE GENERATORS FOR PORTABLE USE (FTCN) GENERAL

This category covers internal-combustion-engine-driven generators rated
15 kW or less, 250 V or less, which are provided only with receptacle outlets
for the ac output circuits. The generators may incorporate alternating or
direct-current generator sections for supplying energy to battery charging
circuits.
This diagram shows no size but does show ONLY receptacle connections

When a portable generator is used to supply a building wiring system:
1. The generator is considered a separately derived system in accordance
with ANSI/NFPA 70, ??National Electrical Code?? (NEC).

In accordance with what jwelectric mentioned, if a portable is UL listed it must have its neutral bonded to the frame.

2. The generator is intended to be connected through permanently
installed Listed transfer equipment that switches all conductors other
than the equipment grounding conductor.

That appears to be correct in the slide

3. The frame of a Listed generator is connected to the equipment grounding
conductor and the grounded (neutral) conductor of the
generator. When properly connected to a premises or structure, the
portable generator will be connected to the premises or structure
grounding electrode for its ground reference.

If this is the case how can any UL Listed portable generator be considered a non-SDS ?

4. Portable generators used other than to power building structures are
intended to be connected to ground in accordance with the NEC.

 

[jwelectric]

OK,This diagram shows no size but does show ONLY receptacle connection
.

The cord plugs into the inlet at the house but it originates at the generator on terminals. This generator can be installed either as a SDS or as a non-SDS

If the generator has receptacles mounted on the frame then those receptacles must comply just as any receptacle installed in the building. The EGC of that receptacle must be bonded to the neutral for a low impedance fault clearing path. Generators such as the one below are dangerous if the neutral is not bonded to the frame as anyone using the generator as a stand-alone unit would have no fault clearing path and could possibly end up holding something in their hand that has a potential of 240 volts.



The big problem with understanding the requirements outlined in the NEC is that a lot of people think of a portable generator as being one such as in this post and cannot imagine a portable generator as in the post above. Both generators are portable but the one in this post is the one outlined in FTCN.

 

[don_resqcapt19]

...
If the generator has receptacles mounted on the frame then those receptacles must comply just as any receptacle installed in the building.
...

Must comply with what?

 

[jwelectric]

Must comply with what?

250.26, 406.9, and any other section of the NEC

 

[don_resqcapt19]

250.26, 406.9, and any other section of the NEC

250.26 or the other sections that tell us almost the same thing is where I thought you were going with this. It is my opinion that compliance with that, starting with the 2008 code, is no longer possible for a portable generator unless you make a connection a grounding electrode.
In the 2005 code, it was clear that the frame of the portable generator could be used as the grounding electrode to make the output of the generator a "grounded system".

2005 NEC: Grounded. Connected to earth or to some conductive body that serves in place of the earth

The metal frame of the portable generator was the conductive body that serves in place of the earth and let us have a "grounded system" supplied from a portable generator without a grounding electrode.

Now comes the 2008 code, and there is no longer a way to supply a "grounded system" from a portable generator unless you make a connection to a grounding electrode.

Grounded (Grounding). Connected (connecting) to ground or to a conductive body that extends the ground connection.

The change in the definition makes it impossible to supply a grounded system unless that system has a connection to a grounding electrode.

 

[jwelectric]

02 (C) Grounded Conductor Bonding. A system conductor that is required to be grounded by 250.26 shall be bonded to the generator frame where the generator is a component of a separately derived system.

05 (C) Grounded Conductor Bonding A system conductor that is required to be grounded by 250.26 shall be bonded to the generator frame where the generator is a component of a separately derived system

08 (C) Grounded Conductor Bonding. A system conductor that is required to be grounded by 250.26 shall be connected to the generator frame where the generator is a component of a separately derived system

11 (C) Grounded Conductor Bonding. A system conductor that is required to be grounded by 250.26 shall be connected to the generator frame where the generator is a component of a separately derived system.

If we go all the way back to the 1993 cycle we find similar wording but every one of the cycles all the way back to the ?93 in the FPN/IN clearly state that a generator that fits the description outlined in A and B is to be connect to a premises wiring as a SDS.

250.34 (A) & (B) relieves the requirement to connect a stand-alone generator to earth but C in all the code cycles state that the conductor that is required by 250.26 to be connected to earth is to be connected to the frame of the generator. The frame of the generator is the earth connection.

If a stand-alone generator is connected to a premises wiring system as a SDS the connection to earth takes place through the bonding conductor between the generator and the premises equipment. All metal in the premises wiring is bonded to the grounding electrode conductor at the service equipment of the premises wiring system thus the generator is also connected to earth.

Many try to use the reference in (C) to say ?if we float the neutral then the generator is a non-SDS?, but by doing so causes the other receptacles mounted on the frame to be non-code compliant and have the ability to become very dangerous. When the neutral is disconnected from the frame the devices mounted there upon are protected only from overcurrent and not protected from ground fault.

The GFCI devices will clear a ground fault on the load side of the device but will do nothing to stop a fault on the line side or clear a hot EGC. This is accomplished only through bonding the neutral to the frame.