Portable generator question

[kwired]

Maybe they do it differently in your part of the country, but I have not seen anything that does not come with the oil already in it here, this includes pressure washers, lawnmowers, ect. All of the Generac Guardian generators arrived at our warehouse full of oil. Now the larger generators do not come with oil, but is added by the startup mechanic.

Do you purchase them still packed in the box or does the store do any required assembly and add the oil? They will not have any fuel in them at all because fire codes will not allow that in the store. Units that are display models will have had all assembly and oils added by store employees when setting them up for display - but no fuel.

 

[Bernard1599]

The following is a Mike Holt comment regarding the OP:

Generator – If the grounded (neutral) conductor in a transfer switch is not opened, then the grounded (neutral) from the generator will be solidly connected to the utility’s service grounded (neutral) conductor. Under this condition, the generator is not a separately derived system, and a neutral-to-case bond shall not be made at the generator or at the generator disconnect [250.20(D) FPN 1].

If a neutral-to-case bond is made at both the generator and generator disconnect, then objectionable neutral current will flow through metal raceways and grounding and bonding path to the power supply.

See the complete article here:
http://www.mikeholt.com/mojonewsarchive/GB-HTML/HTML/Neutral-to-GroundConnections~20020521.htm

 

[jwelectric]

I am here at the Southern Sectional in Chattanooga and this very subject came up today in question 36 fielded by Mark Ode. According to him a portable generator that is self contained is to be connected to premises wiring it MUST switch the neutral conductor.

I went to the mike and asked point blank about the male plug and small single circuit transfer switches and his answer was this is not allowed for the portable generators that contain receptacles.

Now it doesn?t much matter what anyone else has to say does it?

 

[don_resqcapt19]

I am here at the Southern Sectional in Chattanooga and this very subject came up today in question 36 fielded by Mark Ode. According to him a portable generator that is self contained is to be connected to premises wiring it MUST switch the neutral conductor.

I went to the mike and asked point blank about the male plug and small single circuit transfer switches and his answer was this is not allowed for the portable generators that contain receptacles.

He can't make that a blanket statement. Many portable generators have no need to switch the neutral as it is not bonded at the generator.

Now it doesn’t much matter what anyone else has to say does it?

Why not? That is not a FI or panel statement. It is just an opinion and no more valid that opinions given by others who study and work with the code.

 

[jwelectric]

Brother Don one could say that it is nothing more than opinion if one wanted to but this discussion went on for a pretty long while as Mark explained UL Standard 2200 and 2201 and how these standards tied into the portable generator.

Standard 2201 mandates that generators that have receptacles mounted on the frame are to have the neutral bonded to the frame period. UL White book FTCN mandates that any of these generators that are connected to the building must have the neutral switched.

Portable generators that do not have receptacles mounted on the frame can be installed as either SDS or non-SDS.

No Don it is not his opinion but what UL mandates so it must be. Accept it or not it is what it is.

 

[don_resqcapt19]

Brother Don one could say that it is nothing more than opinion if one wanted to but this discussion went on for a pretty long while as Mark explained UL Standard 2200 and 2201 and how these standards tied into the portable generator.

Standard 2201 mandates that generators that have receptacles mounted on the frame are to have the neutral bonded to the frame period. UL White book FTCN mandates that any of these generators that are connected to the building must have the neutral switched.

Portable generators that do not have receptacles mounted on the frame can be installed as either SDS or non-SDS.

No Don it is not his opinion but what UL mandates so it must be. Accept it or not it is what it is.

Then there are a lot on non-ul portable generators out there as there are a number from the major manufacturers that have unit mounted receptacles and do not have the neutral bonded to the generator frame. That is not an opinion, it is a fact and my point is that you can't make a blanket statement that a cord and plug connected transfer device must have the neutral switched. There is nothing to require that a portable generator be a listed item and if it is not listed there is nothing to require compliane with standard 2201.

If the generator neutral is bonded, then the code does require neutral switching.

 

[hillbilly1]

Then there are a lot on non-ul portable generators out there as there are a number from the major manufacturers that have unit mounted receptacles and do not have the neutral bonded to the generator frame. That is not an opinion, it is a fact and my point is that you can't make a blanket statement that a cord and plug connected transfer device must have the neutral switched. There is nothing to require that a portable generator be a listed item and if it is not listed there is nothing to require compliane with standard 2201.

If the generator neutral is bonded, then the code does require neutral switching.

I agree.

 

[iwire]

Then there are a lot on non-ul portable generators out there as there are a number from the major manufacturers that have unit mounted receptacles and do not have the neutral bonded to the generator frame. That is not an opinion, it is a fact and my point is that you can't make a blanket statement that a cord and plug connected transfer device must have the neutral switched. There is nothing to require that a portable generator be a listed item and if it is not listed there is nothing to require compliane with standard 2201.

If the generator neutral is bonded, then the code does require neutral switching.

Well put.

My own 5500 watt unit has receptacles and a floating neutral, I do not know if it is listed or not I have never looked.

 

[stickboy1375]

Well put.

My own 5500 watt unit has receptacles and a floating neutral, I do not know if it is listed or not I have never looked.

and why would you?

 

[kwired]

If the generator neutral is bonded, then the code does require neutral switching.

Just what does switching the neutral accomplish in this situation?

If system bond is installed at service like it supposed to be, it still puts neutral current from generator in parallel over the EGC when the switch is closed in the generator position

 

[don_resqcapt19]

Just what does switching the neutral accomplish in this situation?

It meets the code rules
I don't see a real world issue with a parallel path for these small generator applications. Just look at a standard service where there are code required parallel paths between the utility and the service disconnect. As I have said a number of times, there is some magic that makes the flow of electrons on parallel paths on the load side of the service disconnect very dangerous, but flow on parallel paths on the line side of the service disconnect is perfectly safe.

If system bond is installed at service like it supposed to be, it still puts neutral current from generator in parallel over the EGC when the switch is closed in the generator position

It shouldn't in a correctly installed system as you should not have both the system bonding jumper and the main bonding jumper in the circuit at the same time.

 

[kwired]

It meets the code rules
I don't see a real world issue with a parallel path for these small generator applications. Just look at a standard service where there are code required parallel paths between the utility and the service disconnect. As I have said a number of times, there is some magic that makes the flow of electrons on parallel paths on the load side of the service disconnect very dangerous, but flow on parallel paths on the line side of the service disconnect is perfectly safe.

It shouldn't in a correctly installed system as you should not have both the system bonding jumper and the main bonding jumper in the circuit at the same time.

I guess you are probably right on the correctly installed system and no parallel path.

I have on my mind the hundreds of transfer switches that the POCO installs on their service pole in this rural area.

It is an all in one meter socket with double throw switch. No fuses or breakers, pretty sure it is not UL listed, I can not buy them at supply house - probably in part because they are not listed. People have been connecting portable generators to them for years. There generally is no requirement for it to be inspected. If I were to refuse to put a pigtail for a generator on it because it is not code I promise you they will either do it themselves or find someone else to do it. We are talking hundreds or even thousands of dollars price difference for the correct setup vs 6 feet of cord and a plug.

 

[jwelectric]

I have a question for all those who state that these little generators are just fine with a floating neutral if you don?t mind answering a question for someone as opinionated as me.

Just what happens when there is something plugged into the 120 volt receptacle and for whatever reason the other leg of the generator shorts to the frame?


I would never allow a generator that had the devices mounted to the frame to leave my presence with a floating neutral for any reason.

 

[kwired]

I have a question for all those who state that these little generators are just fine with a floating neutral if you don?t mind answering a question for someone as opinionated as me.

Just what happens when there is something plugged into the 120 volt receptacle and for whatever reason the other leg of the generator shorts to the frame?


I would never allow a generator that had the devices mounted to the frame to leave my presence with a floating neutral for any reason.

Then that leg becomes the line that has a ground reference. There is still no more shock hazard then there is with a normal grounded system. Overcurrent protection will not trip until there is a fault of another conductor.

Once that line becomes grounded it is basically same situation we have with a corner grounded three phase system.

Everyone gets hung up on thinking you have to ground the neutral. Although that is preferred, and usually required, you can ground any conductor of any system, but you can not ground two conductors.

 

[iwire]

Just what happens when there is something plugged into the 120 volt receptacle and for whatever reason the other leg of the generator shorts to the frame?

It would then be bonded.

What happens in a building when a neutral touches ground?

Both are violations but both are abnormal conditions.

I would never allow a generator that had the devices mounted to the frame to leave my presence with a floating neutral for any reason.

Uh huh.

 

[jwelectric]

Then that leg becomes the line that has a ground reference.

Wouldn't this mean that there would now be a difference in potential of 240 volts?

What happens in a building when a neutral touches ground?

We are not talking about the neutral touching ground but the line touching the equipment grounding conductor that does not have the neutral bonded to the frame. It will not open the overcurrent device and there will be 240 volts present on the 120 volt circuit.

Well I suppose that we should just disregard any and all of the scope of the NEC where it says something about safeguarding of persons and property from hazards arising from the use of electricity.

There is a good reason why FTCN was published although some don?t seem to understand.

 

[hillbilly1]

Wouldn't this mean that there would now be a difference in potential of 240 volts?

We are not talking about the neutral touching ground but the line touching the equipment grounding conductor that does not have the neutral bonded to the frame. It will not open the overcurrent device and there will be 240 volts present on the 120 volt circuit.

Well I suppose that we should just disregard any and all of the scope of the NEC where it says something about safeguarding of persons and property from hazards arising from the use of electricity.

There is a good reason why FTCN was published although some don?t seem to understand.

Apparently all of the engineers and manufactures don't seem to understand either then, or the bond would already be there from the factory.:roll: I have an old 5kw portable where the owners manual shows a diagram and a picture or a 15R male plug with a jumper from ground to neutral to be used if a neutral is required if using the 240 volt receptacle. The Generac home generators have the "floating" neutral because they use a two pole switch.

 

[don_resqcapt19]

...We are not talking about the neutral touching ground but the line touching the equipment grounding conductor that does not have the neutral bonded to the frame. It will not open the overcurrent device and there will be 240 volts present on the 120 volt circuit.

I have no idea why they are made that way, but they are. I do know that the OSHA rules specifically permit it for a two wire generator, but prohibit it for a 3 wire one for the very reason you stated, there is a possibility of a 240 volt shock if there are two different faults at the same time. However if the circuits being used are 120 and GFCI protected, a shock caused by the two faults would trip the GFCI. As far as having 240 on the equipment, the equipment itself, will only see 120, no matter what conductor is bonded. The issue is the possibility of a 240 volt shock if the second conductor would fault.

Well I suppose that we should just disregard any and all of the scope of the NEC where it says something about safeguarding of persons and property from hazards arising from the use of electricity.

While the use of the portable generator to supply "premisis" wiring is within the scope of the NEC, the design and construction of the generator itself is not.

There is a good reason why FTCN was published although some don?t seem to understand.

What is FTCN?

 

[Bernard1599]

I found a Honda service bulletin on line dated August 2003. It suggests corrective action for removing the N-G bond when connected to premises wiring. See below:

 

[roger]

If we just leave out the EGC from the generator to the switch we can leave the jumper in place and not have a problem.

Consider the illustration below

BTW, I know what the code requires but, I don't see a problem if we were to not install an EGC in a NON-SDS portable generator installation

Roger