An interesting survival solution...

[Bill906]

I disagree.
You claim to understand electricity better than me. Again I ask:

Please explain exactly what is unsafe about using a portable generator without connecting it to the dirt.

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[ajdelange]

I disagree.
You claim to understand electricity better than me.

I have two degrees in electrical engineering and practiced it for 45 years so, yea, I picked up a few tidbits here and there. And you?

Again I ask:

Please explain exactly what is unsafe about using a portable generator without connecting it to the dirt.

I wouldn't have to explain that to my electrician.
I wouldn't have to explain that to a county building inspector
I wouldn't have to explain that to the guy that fixes my airconditoner/heat pumps
I wouldn't have to explain that to one of my engineering colleagues
I wouldn't have to explain that to the SAE committee that promulgated the J1772 charging standard

But you require an explanation. From that I have assumed that you don't know very much about electricity. But I could be wrong. I will try to explain it to you but because it seems we may not be speaking the same language it might help if you would lay our your industry relevant education and professional experience.

I can say, purely in layman's terms, that if nothing ever failed we wouldn't have grounding/earthing requirements (that's not 100% true but it is applicable to this case). The earthing requirement is there to protect us from faults with a fault being an unintended current path - not necessarily a short, just a leak. If in charging a car with an ungrounded generator a couple of these leakage paths open up in the wrong places the potential of the car body could rise to as much as 240 V above ground potential. If you are standing on the ground and touch the car you will receive a shock. If the generator is grounded the car body will always be at ground potential and you will too so even though these faults be present you will not be shocked.

 

[Frankenblob]

In the video i alluded to initially, the gentleman ran a grounding wire (booster cable) to his houses grounding wire, but, according to him, it didnt work.

Now I could not follow his set-up, i.e. booster cable out from grounding nut then clamped to grounding wire of house, it may have been possible that he attached the + cable to the generator then the - end to the grounding wire which then is useless, didnt have the other ends of his new wires fixed in place, broken jumper cables....

Lets say all 3 above were correctly connected , is there another reason(s) it didnt ground according to the charging cord non-working status?

 

[Luke42]

Please explain exactly what is unsafe about using a portable generator without connecting it to the dirt.

Voltage is a relative measure.

When you're powering something on a generator, you're using the voltage DIFFERENCE between the hot wire and the neutral wire.

That works great on the frictionless infinite plane of imaginary physics lessons. However, the real world is more complicated.

What is the voltage of the neutral wire, relative to the surrounding environment?

It's static voltage of thst neutral line could be a million volts (when compared to its surrounding environment), for all we know. The generator doesn't know. The load doesn't know, it's happy with the 110VAC differential voltage it's seeing. And you don't know either.

Until you touch the surrounding environment (with your feet) and the case of an electrically powered device (with your hand). Then you'll equalize the potential through your body, whatever it is. If the difference is low you won't feel anything and won't notice this is happening. If the potential being equalized is big enough, though, it will kill you.

This is why birds can sit on 16kv power lines. If you took a multimeter and measured the voltage DIFFERENCE between the bird and the power line, it would be darned near 0V. If you measure the difference between the bird and the ground, though, it would kill them -- but they're small, so they can't touch the conductor abd the found at the same time.

If you measure the difference between neutral on your generator, and the surrounding environment, it could be anything. So, you make it the same by trying it to ground in a deliberate way.

So, this raises the question of how you've lived this long without killing yourself with electricity. Electrical engineers design things to handle every case. Most of the time, a little bit of humidity in the air will gradually cause the status voltages to equalize over time. That's why you get fewer static shocks in the summer. But "most of the time" just isn't good enough when it comes to an engineer's ethical responsibility to ensure that their systems don't kill people.

P.S. Now that you understand that an object's static voltage can vary wildly when measured against its surrounding environment, the next question is why your gasoline car doesn't explode due to the combination of sparks and gas fumes which naturally occur when you put the gas nozzle into the filler neck. The answer to that one is far more subtle than most people appreciate, and it's very much related to electrical grounding.

 

[Crissa]

ajdelange is still wrong on this.

He's making several fallacies, arguing out of authority (and false authority) rather than actual facts.

There is a reason that we connect the neutral to ground near the source: To reduce the voltage between neutral and ground.

However, the ground to electronics is all relative. No EV can tell if the neutral is properly grounded because it isn't grounded to the earth, either. It can only know if the ground wire goes nowhere. And most don't care, so I don't know why ajdelange asserted it would. Ground isn't used in 240v charging systems.

This entire argument is stupid and perpendicular to the original topic.

-Crissa

 

[ajdelange]

I did not state one assumption that I should have and that is that the generator is sitting on the ground. If it is sitting in the truck bed so that it is isolated from the ground and a bonding plug is in place then the generator "floats" with the car body and the conductivity of the tires prevents it from floating very far. A ground rod would not buy you so much in that case.

As an aside, this is why the generator in a hybrid does not need to be earthed.

 

[Newton]

So now that thats over...

what about my idea to jack up the back of the CT, or any rwd ev, rotate the back tires with some device (like a water wheel) would this be able to charge the car via regen? (asuming you can get it spinning fast enough)

 

[Crissa]

Sure. It's more a matter of having enough torque.

-Crissa

 

[ajdelange]

In the video i alluded to initially, the gentleman ran a grounding wire (booster cable) to his houses grounding wire, but, according to him, it didnt work.

Now I could not follow his set-up,

Lets say all 3 above were correctly connected , is there another reason(s) it didnt ground according to the charging cord non-working status?

Your description isn't sufficient for me to determine what he did wrong. So let's look at this diagram which shows, in greatly simplified form, a car's charger connected to a properly grounded system.

A properly set up supply has 4 wires Red, Black, White and Green (US). The R and B wires are attached to the outside connections of a pair of coils which are joined at their other ends and a white wire is connected to that common point. The coils each have 120 VAC across them so the Red wire is at potential 240 V relative to the Black wire and each of the Red and the Black are at 120V relative to the White wire. The White wire is connected to a ground rod and to a green wire, The car charger is 240V equipment and so does not use the white wire (ignore Level 1 charging for the moment). People who know more than I do about electrical safety, and, believe it or not, more than some of the people here who think they know everything about this subject have determined over the years that the configuration in the sketch represents a safe configuration and the codes these people promulgate require that this configuration be used. They have determined that the car's frame should be connected to the same earth ground as the mains and so require that the green wire, which is connected to earth and the center point of the two coils, be connected to the car's frame. To be sure that it is the "relay", K, is connected between the green wire's inlet and the Red wire (or Black). As the diagram shows K sees 120V. If K does not see 120V then it will not signal the contactor in the EVSE to close and allow charging. Thus if the fellow in the video was not able to charge it means that there was not 120V between the green wire and the Red or Black and to get it to work he would have to see to it that there is.

Now that sort of triangular symbol to the left of the G represents the ground rod. Note that it does not have to be present for the charging circuit to work. All that is necessary is that W and G be tied together. The OEMs (and standard writers) know that in any residential or commercial building in the civilized world the ground rod will be present and connected to the junction of W and G. They know, therefore, that if K sees 120V that the frame of the car is earthed. But you can take a pair of wire cutters and disconnect the ground rods at your home (there are two - one wired to the bonding screw in you service entrance and another at the pole or vault or wherever the transformer that serves your building is located) and you car will charge just as it did before,

Now note that I have not yet said what the diagram represents. In fact it represents either your house wiring (in which case the two coils are wound on a core in the transformer) or a generator (in which the two coils are wound on the generator's stator). Thus, just as with the house, it is necessary and sufficient that the W and G wires be connected and, just as with the house, the ground rod is optional. It may require a knowledge of electricity (in particular how to read a circuit diagram) that is evidently beyond what some readers possess to be able to see why that is so in terms of fault currents but any rational person ought to be able to understand that the ground rod was put there to improve the safety of residential systems and that it should, thus, enhance the safety of generator based systems too,

 

[Bill906]

Under the following conditions, OSHA directs (29 CFR 1926.404(f)(3)(i)) that the frame of a portable generator need not be grounded (connected to earth) and that the frame may serve as the ground (in place of the earth):

https://www.osha.gov/OshDoc/data_Hurricane_Facts/grounding_port_generator.html

Yes, if the difference in voltage potential is great enough between the ground and the CT and you are touching both a current will flow though your body. But that statement is true regardless of whether you’re using a generator or not. Using your logic it is unsafe to ever have anything metal not connected to dirt for fear the voltage potential between it and ground could shock you.

Also confused on how when the generator is on the ground the voltage potential between the dirt and the CT may get to dangerous levels, but when the generator is on the CT the tires magically become conductors?

Not sure how my education or industry background makes a difference. My guess is you’re wondering if I’m smarter than you. What I said does not change meaning if I have a PhD in engineering or if I’m working on getting my GED. I stated there is no reason to connect a portable generator to a rod in the dirt. I stand by that statement and listed one source in this post that backs that up. I’ve listed at least one other source when we went over this last time.

 

[Frankenblob]

Your description isn't sufficient for me to determine what he did wrong. So let's look at this diagram which shows, in greatly simplified form, a car's charger connected to a properly grounded system.

A properly set up supply has 4 wires Red, Black, White and Green (US). The R and B wires are attached to the outside connections of a pair of coils which are joined at their other ends and a white wire is connected to that common point. The coils each have 120 VAC across them so the Red wire is at potential 240 V relative to the Black wire and each of the Red and the Black are at 120V relative to the White wire. The White wire is connected to a ground rod and to a green wire, The car charger is 240V equipment and so does not use the white wire (ignore Level 1 charging for the moment). People who know more than I do about electrical safety, and, believe it or not, more than some of the people here who think they know everything about this subject have determined over the years that the configuration in the sketch represents a safe configuration and the codes these people promulgate require that this configuration be used. They have determined that the car's frame should be connected to the same earth ground as the mains and so require that the green wire, which is connected to earth and the center point of the two coils, be connected to the car's frame. To be sure that it is the "relay", K, is connected between the green wire's inlet and the Red wire (or Black). As the diagram shows K sees 120V. If K does not see 120V then it will not signal the contactor in the EVSE to close and allow charging. Thus if the fellow in the video was not able to charge it means that there was not 120V between the green wire and the Red or Black and to get it to work he would have to see to it that there is.

Now that sort of triangular symbol to the left of the G represents the ground rod. Note that it does not have to be present for the charging circuit to work. All that is necessary is that W and G be tied together. The OEMs (and standard writers) know that in any residential or commercial building in the civilized world the ground rod will be present and connected to the junction of W and G. They know, therefore, that if K sees 120V that the frame of the car is earthed. But you can take a pair of wire cutters and disconnect the ground rods at your home (there are two - one wired to the bonding screw in you service entrance and another at the pole or vault or wherever the transformer that serves your building is located) and you car will charge just as it did before,

Now note that I have not yet said what the diagram represents. In fact it represents either your house wiring (in which case the two coils are wound on a core in the transformer) or a generator (in which the two coils are wound on the generator's stator). Thus, just as with the house, it is necessary and sufficient that the W and G wires be connected and, just as with the house, the ground rod is optional. It may require a knowledge of electricity (in particular how to read a circuit diagram) that is evidently beyond what some readers possess to be able to see why that is so in terms of fault currents but any rational person ought to be able to understand that the ground rod was put there to improve the safety of residential systems and that it should, thus, enhance the safety of generator based systems too,

What I asked was the man in the video connected a jumper cable to the generator's grounding nut (via a copper ring terminal) and then the other end to a grounding wire (via the jumper cables copper tooth clamp) he recently put in in his garage as part of a new electrical set-up. But this attempt to ground the generator did not work-witness the Tesla charger blinking red.

So, I mentioned 3 possible ways that the generator wasn't grounded or couldn't achieve ground. 1) breach in jumper cable 2) connected the red/positive on generator then connected the black/negative end to the houses grounding wire. 3) if 2 above was done correctly then the houses grounding wire was not connected to the mains grounding panel.

Are there any other ways grounding may not have been achieved?

 

[ajdelange]

Under the following conditions, OSHA directs (29 CFR 1926.404(f)(3)(i)) that the frame of a portable generator need not be grounded (connected to earth) and that the frame may serve as the ground (in place of the earth):

https://www.osha.gov/OshDoc/data_Hurricane_Facts/grounding_port_generator.html

https://www.osha.gov/OshDoc/data_Hurricane_Facts/grounding_port_generator.html

Yes, it does allow that. What I can't figure out is why. Clealy a simple ground fault would put the frame of any tool connected to such a generator at 120 V.

Yes, if the difference in voltage potential is great enough between the ground and the CT and you are touching both a current will flow though your body. But that statement is true regardless of whether you’re using a generator or not. Using your logic it is unsafe to ever have anything metal not connected to dirt for fear the voltage potential between it and ground could shock you.

My dear fellow, it is not my logic. It is the logic of the NFPA and all the similar agencies around the world. A point I keep stressing and you keep choosing to ignore is that your house is wired based on this logic. Why do you choose to reject it when using a generator?

I do recognize that it represents a belt and suspenders approach. I do not drive a ground rod when I use a portable generator (which is a very, very rare occurrence).

Also confused on how when the generator is on the ground the voltage potential between the dirt and the CT may get to dangerous levels, but when the generator is on the CT the tires magically become conductors?

The tires don't become conductors. They are always conductors. They contain enough carbon to enable them to bleed off the static charge picked up when driving through dusty air etc.

Not sure how my education or industry background makes a difference. My guess is you’re wondering if I’m smarter than you.

I'll stipulate that you are smarter than I am. What I wanted to know is whether you have enough knowledge of electrical engineering or practice to make it clear that it isn't a waste of my time to try to explain these things to you in the terms that people with such knowledge and experience use. You don't.

What I said does not change meaning if I have a PhD in engineering or if I’m working on getting my GED. I stated there is no reason to connect a portable generator to a rod in the dirt.

No, it doesn't but if you had a PHD in engineering you wouldn't have said it.

I stand by that statement and listed one source in this post that backs that up.

Wrong and proud of it! I guess I should admire people like that. In any case it is clear that you haven't the depth to understand the source of the potential problem nor the knowledge that society accepts it as a problem. If you did we might have a fruitful discussion as to what OSHA is doing here, whether we should petition them to change, run this past Mike Holt etc. If anyone else wants to undertake to do that I'll participate.

 

[ajdelange]

Are there any other ways grounding may not have been achieved?

Sorry, I still can't answer your question. There are an infinite number of ways to screw this up and one to do it right,

As I hoped I made clear (but apparently didn't) it isn't necessary to ground the generator at all to make it charge. It is only necessary to bond neutral and earth pins on the genny. I didn't see the video but I don't see how running a wire back to the house would help were the bonding not properly done.

I think at this point the questions and answers are:

Q1: Can I use a portable generator to charge my car/CT in the woods?
A1: Yes but you must be sure that the N (white) and G (green) pins are bonded and recognize that charging will be slow. You should also be aware that Tesla advises against charging with "privately owned" generators.

Q2: Do I need to ground the generator?
A2: No but you should be aware that if you do not you will not have the same level of security you achieve at home or at an SC,

 

[Bill906]

Yes, it does allow that. What I can't figure out is why.

Instead of accepting you are wrong you assume you know better than OSHA?

Clealy a simple ground fault would put the frame of any tool connected to such a generator at 120 V.

You keep saying the reason for connecting neutral to the ground pin is to trick the car into thinking it is connected to dirt. This is not the reason. If the ground pin which is connected to the generator frame is also connected to neutral any ground fault (hot contacting frame) would cause a hot to neutral short. Either tripping a breaker (most likely) or if no breaker blowing a fuse or other conductor to stop power flow. None of what I just described would need a connection to dirt.

I do not drive a ground rod when I use a portable generator (which is a very, very rare occurrence).

Now we are at the part where you talk in circles. I said you don’t need to connect the generator to dirt. You attacked me, said I don’t know how electricity works. Went on and on without any sources to back your claims. And now you say you do the exact thing I said was ok to do.

Side Note: You mentioned the NEC multiple times. I do not believe NEC says anything about portable generators used to charge an electric vehicle. I believe NEC only deals with buildings and other structures. It may address connecting a portable generator to a structures power network but that is not what we are talking about. I could be wrong on this however, I am not an NEC expert and I do not have the time to research this.

 

[ajdelange]

Instead of accepting you are wrong you assume you know better than OSHA?

Please read the posts before replying. At least the recent ones. I summarized in the last one with

Q1: Can I use a portable generator to charge my car/CT in the woods?
A1: Yes but you must be sure that the N (white) and G (green) pins are bonded and recognize that charging will be slow. You should also be aware that Tesla advises against charging with "privately owned" generators.

Q2: Do I need to ground the generator?
A2: No but you should be aware that if you do not you will not have the same level of security you achieve at home or at an SC,

Which one of those statements is wrong?

you assume you know better than OSHA?

As I never contradicted the OSHA statement there has never been any evidence here that I think I know better than OSHA. But, in fact, OSHA is a government agency. I certainly hope I in fact do know better than they do. Lord knows the USG paid me enough money to be smarter than they are over the years! I am, and said, I would be, surprised if they waive grounding for portable use but they do.

You keep saying the reason for connecting neutral to the ground pin is to trick the car into thinking it is connected to dirt. This is not the reason.

Yes it is. This is evidently beyond your ability to comprehend so there isn't much point in running it around again.

If the ground pin which is connected to the generator frame is also connected to neutral any ground fault (hot contacting frame) would cause a hot to neutral short.

A ground fault is a fault to ground. A fault to the frame is not a ground fault unless the frame is grounded. A fault will not trip the breaker unless the fault current exceeds the protective device rating. The danger here is leakage level ground faults (I am envisioning a frayed extension cord lying on wet grass or something of that sort) and it is indeed faults of that sort that has driven design of our modern grounded wiring practices.

None of what I just described would need a connection to dirt.

As you can't grasp the technical explanation I would think you would ask yourself why, if none of this is necessary, codes require your house to be wired with a grounded system, why UL ratings require grounding pins etc.

Now we are at the part where you talk in circles. I said you don’t need to connect the generator to dirt. You attacked me, said I don’t know how electricity works.

As I have said in several posts that you do not need to connect the generator to ground (see my last post or the quote of it above) but that it confers additional safety benefits then logic says that your ability to understand the nature of the additional benefits is the basis for the attack. No need for me to comment on your problem with electricity. I think you have demonstrated that pretty convincingly on your own.

Went on and on without any sources to back your claims.

Yes, I cited NEC/NFPA as a source several times as you even note here

Side Note: You mentioned the NEC multiple times. I do not believe NEC says anything about portable generators used to charge an electric vehicle.

Yes, the NEC does cover portable generators in Article 250.34. It has almost the same wording as the OSHA reg. Again I am quite surprised at this. With the NEC, however, I have to opportunity to fill out a card and send it into NFPA pointing out that allowing ungrounded portable generators does, obviously, increase risk. I guess the reasoning is that nobody is going to ground a portable generator (actually, smart people do as some of them have posted that they do so here and in other fora) and in the woods there is no one to check for NEC compliance anyway.