Portable Generators and GFCIs 2011 NEC

[tom baker]

2011 NEC (590.6)requires portable generators 15 KW and less to:
1. All 15-20-30 125/250 Volt receptacles to be GFCI protected
2. Those receptacles above must have bubble covers
3. You can use a portable GFCI on a generator mfg or remfg prior to Jan 1, 2011

Please understand that when the generator is used with a MTS, the GFCI will trip due to the main bonding jumper. This will cause problems, and not sure what will happen with homeowners.

Questions
The assumption is generators mfg after Jan 1, 2011 will have GFCI protection. Is this a UL requirement?
Can we enforce the Jan 1, 2011 requirement in an area where the 2011 NEC is not adopted yet?
If the generator is sitting on a truck bed, isolated from earth, and there is a faulty tool, will there be a ground fault path for the GFCI to trip?

I looked at some Honda generators today. The construction generators have GFCI protection for the receptacles.

 

[don_resqcapt19]

... If the generator is sitting on a truck bed, isolated from earth, and there is a faulty tool, will there be a ground fault path for the GFCI to trip?

It really doesn't make any difference. If there is no ground fault path there is no shock hazard. If there is a path for a 5mA shock, the GFCI will trip

 

[hurk27]

I can't see a need to have the GFCI protection for the twistloc 240/120 volt receptacle that would be the source for a MTS.

This will have grave implications all the way down the line.

This sounds so much like another manufacture pushing to force home owners only be able to buy more costly 15kw or higher to use as a back up generator, or pay more money for purpose built generators that are only for use with transfer switch's.

I hate politics

 

[iceworm]

The following responses are strictly the opinion of an EE that is also an avid/rabid DIY. These opinions carry no weight of law nor should the author be interpreted as having any legal knowledge, unless the subject was a corporate installation per article 590, that occured on my watch - in which case, me, my PE ticket, and the carrier of my E&O insurance would be front and center in the courtroom.

2011 NEC (590.6)requires portable generators 15 KW and less to:
1. All 15-20-30 125/250 Volt receptacles to be GFCI protected
2. Those receptacles above must have bubble covers
3. You can use a portable GFCI on a generator mfg or remfg prior to Jan 1, 2011

Please understand that when the generator is used with a MTS, the GFCI will trip due to the main bonding jumper. This will cause problems, and not sure what will happen with homeowners.

As you noted the NEC requirements are Article 590. Really not applicable to Homeowner (or other) optional standby.

My guess is the HO will take out the generator bonding jumper - as they should.

2011 NEC (590.6)requires portable generators 15 KW and less to:
1. All 15-20-30 125/250 Volt receptacles to be GFCI protected

The assumption is generators mfg after Jan 1, 2011 will have GFCI protection. Is this a UL requirement?

The current UL requirement does not match the NEC.

MARCH 4, 2009 PORTABLE ENGINE-GENERATOR ASSEMBLIES - UL 2201

1.Scope
1.2 These requirements cover 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.
1.3 Generators covered by this standard are normally used by persons other than service personnel.

15.7 Receptacles and ground fault circuit interrupter protection 15.7.7 All 125 V, 15-, 20-, and 30-A AC output circuits shall be protected by Class A ground fault circuit interrupters (GFCI) rated for the current involved and installed in accordance with the manufacturer’s instructions. Receptacles which are not protected by GFCI shall be marked in accordance with 50.3.2.9.

Can we enforce the Jan 1, 2011 requirement in an area where the 2011 NEC is not adopted yet?

I'm not sure who "we" is. If we is the AHJ - how could they enforce a code not yet made into state law?

Current production 15kw (or less), listed, portable gens have gfci on the 125V 15, 20, 30A recetpacles. I have not seen any (yet) with GFCI on 250V, 30A or 20A receptacles.

After 2011 NEC is law, the AHJ (or osha most likely) will provide enforcement on article 590 installations.

I'd guess in areas where the 250V, 20A or 30A gfci receptacle requirement is enforced, there will be a large sale of add-on 30A, 2 pole gfci cord extensions.

I looked at some Honda generators today. The construction generators have GFCI protection for the receptacles.

Did the gfci protected recptacles include a 250V, 30A.? If so, was it 3 blades or 4 blades? As I said, I have not seen any yet, so I'm curious.

If the generator is sitting on a truck bed, isolated from earth, and there is a faulty tool, will there be a ground fault path for the GFCI to trip?

Ah.........No (But I think you already knew that)

This whole issue appears to be an NEC code panel knee jerk reaction to Katrina. Hopefully the NEC code panels and the listing agencies will actually talk to each other. However, I won't be holding my breath.

ice

 

[ceb58]

Can we enforce the Jan 1, 2011 requirement in an area where the 2011 NEC is not adopted yet?

I do not see how it could be enforced. If the state or jurisdiction dose not/ has not adopted the 2011 as of Jan. 1, 2011 then they are still under their present code.

I can't see a need to have the GFCI protection for the twistloc 240/120 volt receptacle that would be the source for a MTS.

This will have grave implications all the way down the line.

This sounds so much like another manufacture pushing to force home owners only be able to buy more costly 15kw or higher to use as a back up generator, or pay more money for purpose built generators that are only for use with transfer switch's.

I hate politics

The only thing I could think would be to treat the gen. as a separately derived system. The MTS would have to be three pole and switch the neutral. It has been discussed here before about larger amp systems having GFI protection and the need to switch the neutral for the same problem.

Not sure of politics but I have seen some real nice set up's by home owners. They need all the protection they can get.

 

[tom baker]

As you noted the NEC requirements are Article 590. Really not applicable to Homeowner (or other) optional standby.
>>> But they will have no choice if that is the way generators are sold
My guess is the HO will take out the generator bonding jumper - as they should.
>>>If the SBJ is removed there is a dangerous condition where fault current can get back into the generator windings if used for other than an MTS application

 

[hurk27]

I do not see how it could be enforced. If the state or jurisdiction dose not/ has not adopted the 2011 as of Jan. 1, 2011 then they are still under their present code.




The only thing I could think would be to treat the gen. as a separately derived system. The MTS would have to be three pole and switch the neutral. It has been discussed here before about larger amp systems having GFI protection and the need to switch the neutral for the same problem.

Not sure of politics but I have seen some real nice set up's by home owners. They need all the protection they can get.

The MBJ would have to be on the utility side of the transfer switch for a GFP or GFCI system to work on or in a generator, if it is in or after the transfer switch it would trip the GFCI in the generator, the neutral bond in the generator would have to serve as the MBJ for when the generator is running, but how do we comply with the requirement of landing the grounding electrodes where the MBJ is?

 

[hurk27]

As you noted the NEC requirements are Article 590. Really not applicable to Homeowner (or other) optional standby.
>>> But they will have no choice if that is the way generators are sold
My guess is the HO will take out the generator bonding jumper - as they should.
>>>If the SBJ is removed there is a dangerous condition where fault current can get back into the generator windings if used for other than an MTS application

Many portable generators have a switch to change between the 120 volt receptacles and the 120/240 twist loc, this switch also lifts the frame bond connection.

( words in red)

I don't follow this?
Lifting the generator neutral to frame bond only disconnects the fault path of the grounding terminals to the neutral so a fault would not have a path back to source, while this would allow the fault to bring the frame of the generator and anything grounded to the frame through the 120 volt receptacle grounding up to the potential of the ungrounded conductor, there would be still only be one other voltage reference point that would provide a return path back to source, this would be the grounded conductor, and as far as I know a person would have to be in contact with the neutral before a shock could happen

 

[jwelectric]

I think that we are missing the whole issue here.
Once the generator is connected by any means to the premises wiring the generator is no longer portable.

In order to be portable it must comply with 250.34(A)(1)&(2)
Who is going to step forward and call the premises wiring system a piece of equipment?

 

[ceb58]

The MBJ would have to be on the utility side of the transfer switch for a GFP or GFCI system to work on or in a generator, if it is in or after the transfer switch it would trip the GFCI in the generator, the neutral bond in the generator would have to serve as the MBJ for when the generator is running, but how do we comply with the requirement of landing the grounding electrodes where the MBJ is?

Wayne, not sure I follow what you are saying. If you treated the gen. as a SDS then the N-G bond would be in the gen. before the OCD. The neutral would be switched in the MTS. So no connection between gen. and utility neutral.
As you I now wonder about the grounding electrode or will 250.34 (A) still be in play?

 

[hurk27]

Wayne, not sure I follow what you are saying. If you treated the gen. as a SDS then the N-G bond would be in the gen. before the OCD. The neutral would be switched in the MTS. So no connection between gen. and utility neutral.
As you I now wonder about the grounding electrode or will 250.34 (A) still be in play?

Yep I kind of got ahead of my train of thought, most MBJ's will be in the disconnect between the utility meter and the transfer switch so with a neutral transfer it would not be a problem as long as the neutral is not bonded anywhere else.

 

[Smart $]

I think that we are missing the whole issue here.
Once the generator is connected by any means to the premises wiring the generator is no longer portable.

In order to be portable it must comply with 250.34(A)(1)&(2)
Who is going to step forward and call the premises wiring system a piece of equipment?

We do not have to call the whole premises wiring system a piece of equipment... only what connects to the other end of a cord with plug. A cord-and-plug connected panelboard would meet the requirement of 250.34(A)(1) or (B)(2), IMO. The NEC defines equipment rather broadly and the connected piece(s) of equipment is(are) not restricted from supplying other loads.

 

[jwelectric]

We do not have to call the whole premises wiring system a piece of equipment... only what connects to the other end of a cord with plug. A cord-and-plug connected panelboard would meet the requirement of 250.34(A)(1) or (B)(2), IMO. The NEC defines equipment rather broadly and the connected piece(s) of equipment is(are) not restricted from supplying other loads.

Now let?s think about this for a second.
In the transfer switch either the grounded neutral of the premises wiring will or will not be switched. In the event the grounded neutral of the premises wiring system was not switched then the generator becomes connected to earth. If the generator is connected to earth how can it be portable?

In order for the generator to be portable it would have to remain a separately derived system and would remain an ungrounded system.
yes? no? idon't know:-?

 

[iceworm]

I think that we are missing the whole issue here. Once the generator is connected by any means to the premises wiring the generator is no longer portable. In order to be portable it must comply with 250.34(A)(1)&(2) Who is going to step forward and call the premises wiring system a piece of equipment.

Yes, exactly. Much better than I said.

>>>If the SBJ is removed there is a dangerous condition where fault current can get back into the generator windings if used for other than an MTS application [

Once the generator is configured for an optional standby for a house, then that is what it is. It is no more dangerous than any other piece of equipment if misused.

Tom B -
The addition of a gfci doesn't change anything as far as the placement of a bonding jumper in the gen. A two wire transfer switch mandates the bonding jumper be removed.

I'm pretty sure everybody already knew that.

ice

 

[jwelectric]

I should have pointed out that we need to pay close attention to the FPN or Information Note if you please under 250.30(A). Those conductors from the generator to the building are feeders and not service conductors.

 

[Smart $]

Now let?s think about this for a second.
In the transfer switch either the grounded neutral of the premises wiring will or will not be switched. In the event the grounded neutral of the premises wiring system was not switched then the generator becomes connected to earth. If the generator is connected to earth how can it be portable?

In order for the generator to be portable it would have to remain a separately derived system and would remain an ungrounded system.
yes? no? idon't know:-?

I thought we were discussing jobsite temporary power. If there is no service, how can a generator not be an SDS. If there is service, we wouldn't need the generator.

Now if the generator is used for standby power, and the neutral is not switched by the MTS, we have an alternate source of power, but not an SDS. Switch the neutral and we have an SDS. But what does this have to do with the generator no longer being portable?

I don't see how earth grounding a portable generator makes it not portable. Additionally, aren't we connecting to receptacles on the portable generator? Unplug and away it can go... fitting my understanding of most anything portable.

 

[jwelectric]

I thought we were discussing jobsite temporary power. If there is no service, how can a generator not be an SDS. If there is service, we wouldn't need the generator.

Would you also agree that we wouldn't need a transfer switch either?

 

[jwelectric]

I buy me a Honda 5500 Watt generator that has handles and wheels. It comes with two 120 volt 20 amp GFCI receptacles and one 240 volt 30 amp receptacle.

I can plug my drill into one of the duplex receptacles and go to drilling. Should there be a ground fault somewhere in the system the equipment grounding conductor will carry the fault current straight to the frame of the portable generator.

Should I connect this same generator to a transfer switch that does not switch the grounded neutral conductor then the bonding at the generator must be lifted. This does not fit the definition of a portable generator as I can no longer plug a piece of equipment into one of the receptacles on the frame of that generator and operate the equipment with any sense of safety making the generator at this point in time no longer portable. (see 250.34 of the NEC)

Once I unplug this generator from this transfer switch that does not switch the grounded neutral I must establish the bonding on the generator before it can be used with the devices on the generator. During this time period the generator is not a portable generator and can not be used by plugging a piece of equipment into the device on the frame of the generator. As outlined in 250.34 for portable generators.

A portable generator is an ungrounded stand alone system. Once the generator becomes grounded it is no longer an ungrounded stand alone portable generator.

Is my dish washer a portable piece of equipment? I can unplug it and move it around any place my heart desires can I not. It must be portable then, right? How about my disposal or my trash compactor?

Should the portable generator not be a separately derived system is it not logical that is must be part of the premises wiring system? If it is part of the premises system how can it be portable???????

 

[iwire]

A portable generator is an ungrounded stand alone system. Once the generator becomes grounded it is no longer an ungrounded stand alone portable generator.

That sure sounds like an opinion and I will consider it one until I am shown a code section that backs that up.

Any chance that a response to this could be concise and not verbose?

 

[jwelectric]

That sure sounds like an opinion and I will consider it one until I am shown a code section that backs that up.

Any chance that a response to this could be concise and not verbose?

Okay here you go

250.34 Portable and Vehicle-Mounted Generators.
(A) Portable Generators. The frame of a portable generator shall not be required to be connected to a grounding electrode as defined in 250.52 for a system supplied by the generator under the following conditions:
(1) The generator supplies only equipment mounted on the generator, cord-and-plug-connected equipment through receptacles mounted on the generator, or both, and
(2) The normally non?current-carrying metal parts of equipment and the equipment grounding conductor terminals of the receptacles are connected to the generator frame.
(B) Vehicle-Mounted Generators. The frame of a vehicle shall not be required to be connected to a grounding electrode as defined in 250.52 for a system supplied by a generator located on this vehicle under the following conditions:
(1) The frame of the generator is bonded to the vehicle frame, and
(2) The generator supplies only equipment located on the vehicle or cord-and-plug-connected equipment through receptacles mounted on the vehicle, or both equipment located on the vehicle and cord-and-plug-connected equipment through receptacles mounted on the vehicle or on the generator, and
(3) The normally non?current-carrying metal parts of equipment and the equipment grounding conductor terminals of the receptacles are connected to the generator frame.
(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.
FPN: For grounding portable generators supplying fixed wiring systems, see 250.20(D).



Now I will admit that I am not the brightest bulb in the box but for someone to say that a generator is portable when it is part of the premises wiring is OPINION and I will believe that such a generator is not a portable generator until someone shows me code text that says different.

Following the code text as outlined in the FPN should a portable generator supply a fixed wiring system we need to see 250.20(D) which leads us to 250.30(A) which tells us to read 1-8. Stop a minute at 250.30(B)(2) which talks about the ungrounded portable generator.

A portable generator is not required to be connected to earth (see text above). If it is not connected to earth then it is a non-grounded system. If it is a non-grounded system and it becomes connected to a system that is grounded then it is no longer the same as it was manufactured and becomes part of the system to which it is connected. If the system to which it is connected is not portable then the generator must comply with 250.35 which does not regulate portable generators but instead regulates generators that are permanently installed. If it is permanently installed even on a temporary basis then during the time that it is permanently installed it is no longer portable plain and simple.