Grounding a portable generator

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Cubey

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I do hope that you are using a gen-set that is listed for use on a RV instead of one from the "big box store"

No, it is not an RV-listed genset. It is a Coleman. However I will be operating the generator about 25-50 feet away from the trailer, not "installing" it into a compartment.
 

Cubey

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Hm, new question but still completely related.

Should the chassis of an RV be connected to ground of the 120v powering it (grid or generator) or should ground be isolated from the chassis.

There seems to be two difference scenarios and therefore two different rules.

1: If using an external portable generator, ground should not be connected to the chassis of the RV/vehicle. (NEC does does not say you must)

2: If using a vehicle mounted generator, you must connect the ground to the chassis. (NEC code says you must).

So would I be safe and correct if my trailer has ground isolated from the chassis?
 

JWelectric

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So would I be safe and correct if my trailer has ground isolated from the chassis?
No!!!!!
This is cleared up in the 2008 code cycle by making the statement in 51.47(R)(4)
ONLY INSTALL A GENERATOR LISTED
SPECIFICALLY FOR RV USE
GENERATOR CIRCUIT. THIS CONNECTION
IS FOR GENERATORS RATED 110–125-VOLT AC,
60 HZ, ______ AMPERES MAXIMUM.
or
ONLY INSTALL A GENERATOR LISTED
SPECIFICALLY FOR RV USE
GENERATOR CIRCUIT. THIS CONNECTION
IS FOR GENERATORS RATED 120/240-VOLT AC,
60 HZ, _______ AMPERES MAXIMUM

Any generator used MUST be bonded to the RV. The panel in the RV MUST be bonded to the frame of the RV
 

Cubey

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No!!!!!
This is cleared up in the 2008 code cycle by making the statement in 51.47(R)(4)
ONLY INSTALL A GENERATOR LISTED
SPECIFICALLY FOR RV USE
GENERATOR CIRCUIT. THIS CONNECTION
IS FOR GENERATORS RATED 110–125-VOLT AC,
60 HZ, ______ AMPERES MAXIMUM.
or
ONLY INSTALL A GENERATOR LISTED
SPECIFICALLY FOR RV USE
GENERATOR CIRCUIT. THIS CONNECTION
IS FOR GENERATORS RATED 120/240-VOLT AC,
60 HZ, _______ AMPERES MAXIMUM

Any generator used MUST be bonded to the RV. The panel in the RV MUST be bonded to the frame of the RV

Where did you find that NEC code 51.47(R)(4)? I can't find *any* mention of it on MilkeHolt.com or in Google at all.

Technically I'm not "installing" such as in a compartment meant for an RV generator or luggage. That may be what NEC code refers to as some folks think it is okay to use a propped open luggage compartment as a means of "installing" a portable generator.

If NEC means you can no longer use any generator that isn't made specifically for RVs, then there is going to be thousands upon thousands of people purposing ignoring NEC code (probably myself included!) all around the country because that just doesn't make sense that you can't use an outdoor generator in a safe fashion (placed at least 25 feet away) to power an RV that has it's bondings done correctly.

About bonding: As I understand it, neutral and ground in the RV's breaker panel should *not* be bonded (since is basically a sub panel) but ground on the panel *should* be bonded to the chassis, regardless of using grid or generator power.
--
Edit: I was mistaken about my trailer not having ground bonded to the chassis. I found where the bare ground comes out and connects to the chassis near the electrical input so it *is* bonded as it should be (ground/chassis is bonded, neutral/ground is not). It should be perfectly safe and up to current NEC code to operate a generator for my trailer, assuming NEC hasn't made it so that you can never use a portable generator to power an RV. That does not make any sense to me if that is the case.
 
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Cubey

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This is from the 2008 code cycle.

I finally found it. You posted it as 51.47(R)(4) instead of 551.47(R)(4)

Also you misquoted it/misunderstood it. What you pasted is what is meant to be printed on a label and attached to RVs in compartments meant for RV generators only. That is not an actual NEC code per say, it is only a label that is required by NEC code for RVs with generator compartments.

Final Action: Accept
(551.47(R)(4))
_____________________________________________________________
Submitter: Code-Making Panel 19,
Recommendation: In the existing Code, 551.47(R)(4), revise the two labels as
follows:
ONLY INSTALL A GENERATOR LISTED SPECIFICALLY FOR RV USE
GENERATOR CIRCUIT. THIS CONNECTION IS FOR GENERATORS
RATED 110-125-VOLT AC, 60 HZ,________AMPERES MAXIMUM.
Or
ONLY INSTALL A GENERATOR LISTED SPECIFICALLY FOR RV USE
GENERATOR CIRCUIT. THIS CONNECTION IS FOR GENERATORS
RATED 120/240-VOLT AC, 60 HZ,________AMPERES MAXIMUM.

That is why there is a blank section in it. It is a label with a form field so they can enter in the correct max amps depending on the electrical system equipped on the RV the label is being attached to.

The NEC code is not banning portable generators from RV use, it is merely revising the label warning about not installing portable generators into generator compartments built into RVs.
 
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Cubey

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I am reading the document now. Code 551.47(4) has to do with RVs with 50A power service and the bit you pasted before is a label as I previously mentioned. Oddly enough, the 2008 code 551.47(4)(D) which should be the final, official version of the revised label 551.47(R)(4) that you mentioned is different. But basically what you pasted is not the NEC code banning use of portable generators with RVs, it only bans sticking one into an RV's generator compartment which unfortunately isn't common sense for some folks.

Section 250.34 of the 2008 code is pretty much the same about grounding and usage of portable generators.

Section 551.30 (Section III - Other power sources) pretty much is referring to "vehicle-mounted" generators for the most part when it discusses ventilation and compartments.

No where in the NEC for 2008, as far as I can find, has portable generators been banned for use with RVs. They are just revising the warning label telling folks not to kill themselves by sticking a portable generator in their "vehicle-mounted" generator compartment.
 
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Cubey

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Check out the emails between Coleman Powermate support and I:

---

Q: Hello. I am a bit confused about grounding issues concerning portable
outdoor generators. The manual states that you must follow NEC code
(250.34) and drive a grounding rod for portable generators. However,
actual NEC code 250.34 (A) Portable Generators, says you do NOT have to
use a "grounding electrode" (grounding rod). So does the Coleman manual
for generators override what NEC code says or is it just that the manual
is mistake about what NEC code says? OSHA also states you do not have to
ground a portable generator. Here are a few links pointing this out:

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

Thank you.

A: We recommend grounding the generator whenever it is in use.


Q: You may recommend it but do you consider it a requirement? And why does the Coleman manual misquote/"lie" about NEC code requiring a ground rod when it doesn't? This is assuming that local city codes won't require it
beyond the NEC code.

A: The metal parts of generator and the grounding terminals of the
receptacles are not bonded to the generator frame, which requires the
generator to be grounded.

It is not absolutely necessary for the generator to be grounded for it
to produce power, but it is a safety feature that will prevent
accidental shock.


Q: In that case, all one must do is bond the receptacles to the frame with
the proper gauge wire, correct?

A: Yes, it's possible.

--

The support guy from Coleman just admitted that if you bond the ground from the generator's receptacles to the frame manually you would not have to use a ground rod. So if your generator happens to be one already bonded in such a way you wouldn't have to do it, otherwise you would have to do it manually to avoid using a ground rod to follow the manufacturer's instructions and NEC code.
 
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BrianJohn

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Not that the support guy knows anything about grounding..but if you happen to talk to him again ask him HOW A GROUND ROD PREVENTS SOMEONE FROM A SHOCK.
 

Cubey

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Not that the support guy knows anything about grounding..but if you happen to talk to him again ask him HOW A GROUND ROD PREVENTS SOMEONE FROM A SHOCK.

I did just that. I replied saying:

"Out of curiosity, how does a ground rod on a stock Coleman Generator
(without receptacle ground bonded to the frame) prevent someone from
being shocked?"


His reply was:

"It's mostly to prevent an accidental shock it the machine would happen
to get wet. Instead of the electricity traveling through the frame it
would travel out through the ground. "
 

BrianJohn

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"It's mostly to prevent an accidental shock it the machine would happen
to get wet. Instead of the electricity traveling through the frame it
would travel out through the ground."


Send them this.

Are you out of your ever loving mind! If the electricity travels THROUGH the ground (which by the way is a less than a fair conductor) where is it going too!

Mother Earth is the harbinger of a lot of things but she could care less if a Coleman generator exist and/or much less if is connected to her backside by means of a STICK IN THE EARTH.

In a short of an energized conductor the the voltage is going to return to it's source, generally by the path of least resistance, though any viable paths may share some of the fault current. We call it a circuit because it is CIRCULAR starts and ends in the generator.


from Wikipedia

An electrical circuit is a network that has a closed loop, giving a return path for the current. A network is a connection of two or more components, and may not necessarily be a circuit.

Oh well hopfully you have your answer to the original post and Coleman is much bigger than me they will continue to do what they do and many if not most electricians, inspectoers and end users will continue to drive ground rods, which in it's self is not bad*, but unecssary

*Unless you hit a high voltage underground cable.
 

480sparky

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His reply was:

"It's mostly to prevent an accidental shock it the machine would happen
to get wet. Instead of the electricity traveling through the frame it
would travel out through the ground. "


I wound then ask, "To where?......" It isn't like a bucket of popcorn that can spill out and make a mess. Electron flow is not affected much by gravity.

Electricity needs a compete circuit in order to flow. If there's a short-circuit in the unit itself, and it is properly bonded and grounded within itself, then the breaker will open.
 

BrianJohn

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Sparky you know durn well that the earth is a gigantic bucket for electrons just waiting to suck up the extra/spare electrons from our wiring errors.
 

Jadnashua

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Having spent some time in the military, grounding things became a big hassle. We often had multiple things connected to separate generators, maybe stuck on top of a mountain, where you couldn't really drive a ground stake. That took some real effort to keep from getting yourself knocked on your butt sometimes. Often it was just to ensure you could drain off a significant static buildup.

FOr a single generator on a single device, a ground rod probably isn't that big of a deal. When you are trying to establish ground planes for things like communications or radar sets, it becomes much more problematic. In the desert, the cooks would order lots of extra salt, and salt down then keep moist the ground rods/cables in order to have a phone or radio system work properly. Sand is a lousy conductor, so a ground rod(s) or burried array of cables often wouldn't work well.

This was more for noise and ground plane, not for safety, although that did come into play as well. It also helped with near (but not direct) lightning strikes.

I wouldn't worry about grounding a generator on an RV. Then again, I don't have one nor am I a licensed electrician:).
 

Cubey

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I wound then ask, "To where?......" It isn't like a bucket of popcorn that can spill out and make a mess. Electron flow is not affected much by gravity.

If there's a short-circuit in the unit itself, and it is properly bonded and grounded within itself, then the breaker will open.

Not much point in asking them anything else. They already admitted that in some cases they don't think you have to drive a rod if the ground in the receptacle is bonded to the generator's frame. A short piece of 12 gauge wire added on would correct this anyway and make it compliant to not needing a ground rod (according to the Coleman support guy anyway).

If in doubt of it already being bonded, I could do it anyway though that could possibly cause a ground loop if it already has ground bonded to the frame but thats about the only risk in adding it. I am already familiar with installing receptacles, switches, light fixtures, etc so routing ground to frame will be no problem at all.

I assume the breaker you refer to are the ones at the trailer's panel.

Going back to a question I asked a bit ago, since I don't think I got an answer or I forgot it and can't find where it answered, should neutral be bonded to ground/frame at the generator? I know it shouldn't be at the trailer's panel. Might be good to play it safe and manually bond neutral to ground just to be safe if it is supposed to be that way.
 
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480sparky

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Sparky you know durn well that the earth is a gigantic bucket for electrons just waiting to suck up the extra/spare electrons from our wiring errors.

From a portable genny? :confused: How do you complete the circuit?

The earth may be capable of 'sucking up' all those electrons that trickle off by screwdriver or I spill out of my pouch, but then how do they get back to the generator?
 

JWelectric

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Going back to a question I asked a bit ago, since I don't think I got an answer or I forgot it and can't find where it answered, should neutral be bonded to ground/frame at the generator? I know it shouldn't be at the trailer's panel. Might be good to play it safe and manually bond neutral to ground just to be safe if it is supposed to be that way.

If the neutral point of the generator is not bonded to the equipment grounding conductors supplied by the generator then the overcurrent device will not operate properly.

We know that the grounded (neutral) must be isolated from the equipment grounding conductors in the distribution panelboard inside the RV as outlined below;
551.45 Distribution Panelboard.
(A) Listed and Appropriately Rated. A listed and appropriately rated distribution panelboard or other equipment specifically listed for this purpose shall be used. The grounded conductor termination bar shall be insulated from the enclosure as provided in 551.54(C). An equipment grounding terminal bar shall be attached inside the metal enclosure of the panelboard.

The lack of bonding the equipment grounding conductors to the grounded (neutral) conductor in the panel inside the RV makes the generator a separately derived system and must be treated thus.

The equipment grounding conductors do not bond in the panel inside the RV so any fault to any metal including the shell of the unit could not return through a path of low-impedance and if the equipment grounding conductors don’t bond to the grounded (neutral) at the generator either then there is a problem.

By bonding the generator the low-impedance path is established and now any and all of the overcurrent devices can function as they were designed.

The driving of a ground rod will play no role in the operation of any overcurrent device and will only protect the generator in the event of lightning, line surges, or unintentional contact with higher-voltage lines. I can’t see either of the latter two taking place if the same cord is used to supply the RV being used from either the generator or the pedestal.
 

Cubey

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If the neutral point of the generator is not bonded to the equipment grounding conductors supplied by the generator then the overcurrent device will not operate properly.

We know that the grounded (neutral) must be isolated from the equipment grounding conductors in the distribution panelboard inside the RV as outlined below;
551.45 Distribution Panelboard.
(A) Listed and Appropriately Rated. A listed and appropriately rated distribution panelboard or other equipment specifically listed for this purpose shall be used. The grounded conductor termination bar shall be insulated from the enclosure as provided in 551.54(C). An equipment grounding terminal bar shall be attached inside the metal enclosure of the panelboard.

The lack of bonding the equipment grounding conductors to the grounded (neutral) conductor in the panel inside the RV makes the generator a separately derived system and must be treated thus.

The equipment grounding conductors do not bond in the panel inside the RV so any fault to any metal including the shell of the unit could not return through a path of low-impedance and if the equipment grounding conductors don’t bond to the grounded (neutral) at the generator either then there is a problem.

By bonding the generator the low-impedance path is established and now any and all of the overcurrent devices can function as they were designed.

The driving of a ground rod will play no role in the operation of any overcurrent device and will only protect the generator in the event of lightning, line surges, or unintentional contact with higher-voltage lines. I can’t see either of the latter two taking place if the same cord is used to supply the RV being used from either the generator or the pedestal.

So is that a "yes" to bonding neutral and "ground" of the generator to the gen's frame manually myself if I'm unsure if it already wired up that way?

If so, would that be a safe way to do it?...
Remove the cover where the receptacles are, link the neutral to ground on all the receptacles with a few short pieces of 12 gauge wire (preferably green insulated wire so it will be properly color coded) and then run a long 12 gauge wire down to the screw that Coleman put for using a grounding rod and attach it there. Oh wait.. I might have to run that wire to the frame, not the screw. Might have to do both actually just to be sure its done properly. Link the 12 gauge wire from neutral/ground bonding at the receptacles to the screw meant for a ground rod and then link the screw to the frame. That would be a full proof way of making sure everything is bonded properly and is attached to the frame.

As I understand it about the RV panel, it is considered a "sub panel" under the NEC code and so neutral & ground must be isolated there. This is because the power source it is getting is supposed to be properly bonded either in a main breaker panel such as in a house, an RV park/campground outdoor breaker panel with GFI receptacles, or bonded at the generator.

(Note: If i say ground I am referring to the wire that goes to the 3rd prong on a 15A receptacle. You seem to do otherwise. I'm confused by the various usage of ground vs grounded vs grounding so I'm keeping it simple by saying "neutral" & "ground")
 

JWelectric

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So is that a "yes" to bonding neutral and "ground" of the generator to the gen's frame manually myself if I'm unsure if it already wired up that way?

If so, would that be a safe way to do it?...
I would recommend that you have this done by a professional. It needs to be done internal of the generator such as this illustration shows.

NeuforGen.jpg


Here the bond was removed because the â€bonding€ took place at the main for the building. The â€bonding€ can not occur at both the generator and the building.

Remove the cover where the receptacles are, link the neutral to ground on all the receptacles with a few short pieces of 12 gauge wire (preferably green insulated wire so it will be properly color coded) and then run a long 12 gauge wire down to the screw that Coleman put for using a grounding rod and attach it there. Oh wait.. I might have to run that wire to the frame, not the screw. Might have to do both actually just to be sure its done properly. Link the 12 gauge wire from neutral/ground bonding at the receptacles to the screw meant for a ground rod and then link the screw to the frame. That would be a full proof way of making sure everything is bonded properly and is attached to the frame.
NO! NO! NO! this is not the way to bond the generator and is doing nothing but causing a more dangerous situation.

As I understand it about the RV panel, it is considered a "sub panel" under the NEC code and so neutral & ground must be isolated there.
There is no such animal called a panelist this is a phrase that has been picked up in the field and has no meaning in the NEC.
What makes the distribution panelboard get called a subpanel is what is supplying the panel. Every panel is supplied by either feeders or service entrance conductors. The RV is supplied through feeders by both the pedestal or generator as either are required to have overcurrent protection for the conductors connected between them and the RV.

This is because the power source it is getting is supposed to be properly bonded either in a main breaker panel such as in a house, an RV park/campground outdoor breaker panel with GFI receptacles, or bonded at the generator.
This is correct

(Note: If i say ground I am referring to the wire that goes to the 3rd prong on a 15A receptacle. You seem to do otherwise. I'm confused by the various usage of ground vs grounded vs grounding so I'm keeping it simple by saying "neutral" & "ground")
Well it is easy to understand what each is called and what each is supposed to do. The words ground vs grounded vs grounding simply mean connect to mother earth. The terms "neutral" & "ground") say the same thing, connected to earth.
The one word you have left out is the most important and it is called bonding and means that the conductors you mentioned have been connected together at the point where the supply of current is taken and in this case the generator.

In earlier post I have pointed out that ANY and ALL generators used for a RV must be listed for the use. Look carefully at the section of the NEC posted below.

551.32 Other Sources.
Other sources of ac power, such as inverters, motor generators, or engine generators, shall be listed for use in recreational vehicles and shall be installed in accordance with the terms of the listing.
Other sources of ac power shall be wired in full conformity with the requirements in Parts I, II, III, IV, and V of this article covering 120-volt electrical systems.

Yes I know and understand that a lot of people do not know about this section and just as many do not understand the requirements of bonding these systems.

In my area there is a slew of RV parks and I get calls all the time about someone using a generator that is not bonded and feeling a tingle on rainy days until I ask on the phone about the electrical connection before I go out on the call. 99% of these calls are about the remote generator that is not properly listed for the use and are not bonded.

The part I like best is when it is still raining and the generator has been set inside a cavity of the RV to protect it from the weather. Now it just became a mounted generator and I recommend to the park manager to either have the RV owner sign a wavier of liability or evict then from the park.

The NEC does not require that the generator being used on a RV be listed because the NEC is making a lot of money from the sale of listed generators but instead the NEC requires that generators be listed for the purpose as a safety issue.
The danger comes when the RV owner wants to save a little money and buy something just because it works without understanding the danger involved.
 
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