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Neutral - Ground Bonding


Dr4Film

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I am having a 2006 Monaco Dynasty fully inspected for a possible purchase by a Certified NRVIA Inspector. He discovered that the Neutral and Ground are NOT bonded in the Main Power Circuit Breaker Panel but the Neutral and Ground ARE bonded in the Inverter Circuit Breaker Panel.

He claims that according to NRVIA code that the neutral and ground should NOT be bonded.

I went into my 2002 Windsor and performed the same tests on my two circuit breaker panels but I got the same results that he did on the Dynasty.

Does anyone on this forum know what our Monaco's should be for neutral/ground bonded or non-bonded?

I know that the Onan Generator has the neutral and ground bonded.

Thanks in advance.

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Your inspector is wrong.  There can be only ONE point where the neutral and ground are bonded, and that is at the source.  For shore power, that would at the transformer (large campground) or the Main Poker panel (at your house or wherever the power come in).  The coaches power panel is similar to a Sub Panel in the NEC.  Therefore the neutral and ground must he separate to the main panel.  No for the "gotcha".  When you disconnect shore power, you also disconnect the ground from the coach.  But we can still have 110 VAC from the inverter.   This I'd handled by (in most cases) the inverter internal transfer switch - not to be confused with the large generator transfer switch.  When the inverter senses loss of incoming 110VAC, it initiates a transfer to the inverter circuit, powered by the battery.  It switched the incoming 110VAC from the main circuit breaker panel to the inverter power, and it continues out the inverter powering the microwave and outlets that were powered by shore power.  At the same time it bonds the ground or neutral together inside the inverter box.  The inverter is now the main source of power, and now the neutral and ground are bonded there.   The only time the neutral and ground should be bonded together in a coach is when no other source of 110VAC is available.  The inverter can not tell where the input 110VAC is coming from so it will not bond the two on the generator.  That is why the generator, when running, is now the main source of 110VAC power, and it will provide the bond between the neutral and ground. 

Hope this helps,  post any questions I didn't address.

   - Rick N.

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I’ll be following. I’m not up on the electrical side as I wish I was. 
 

I don’t have 2 breaker panels to understand the whole flow. Ill start digging. 
 

Congrats on upgrading 

3 minutes ago, waterskier_1 said:

Your inspector is wrong.  There can be only ONE point where the neutral and ground are bonded, and that is at the source.  For shore power, that would at the transformer (large campground) or the Main Poker panel (at your house or wherever the power come in).  The coaches power panel is similar to a Sub Panel in the NEC.  Therefore the neutral and ground must he separate to the main panel.  No for the "gotcha".  When you disconnect shore power, you also disconnect the ground from the coach.  But we can still have 110 VAC from the inverter.   This I'd handled by (in most cases) the inverter internal transfer switch - not to be confused with the large generator transfer switch.  When the inverter senses loss of incoming 110VAC, it initiates a transfer to the inverter circuit, powered by the battery.  It switched the incoming 110VAC from the main circuit breaker panel to the inverter power, and it continues out the inverter powering the microwave and outlets that were powered by shore power.  At the same time it bonds the ground or neutral together inside the inverter box.  The inverter is now the main source of power, and now the neutral and ground are bonded there.   The only time the neutral and ground should be bonded together in a coach is when no other source of 110VAC is available.  The inverter can not tell where the input 110VAC is coming from so it will not bond the two on the generator.  That is why the generator, when running, is now the main source of 110VAC power, and it will provide the bond between the neutral and ground. 

Hope this helps,  post any questions I didn't address.

   - Rick N.

Thanks! This makes sense 

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"The inverter is now the main source of power"

So as you say the neutral and "equipment grounding conductor" should be bonded together with a bonding jumper.

The NEC doesn't address inverters as used in RVs. However the NEC does address separately derived systems which an inverter would fall under. An inverter is referred to as a UPS by electrical  engineers. 

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Our coaches are not a bonded ground system. I found this out when I tried to power my 2008 Dynasty coach with a Honda EU 7000 inverter generator. No power to the coach from the generator. Plug the same cord from the coach into the house power and everything works. The Honda is not a bonded ground like the shore power. I believe your possible new coach is wired correctly. I had to "trick" the generator with a plug wired with a jumper from neutral to the ground and have it plugged in to a outlet on the generator.

 

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1 hour ago, Gary Cole said:

"The inverter is now the main source of power"

So as you say the neutral and "equipment grounding conductor" should be bonded together with a bonding jumper.

The NEC doesn't address inverters as used in RVs. However the NEC does address separately derived systems which an inverter would fall under. An inverter is referred to as a UPS by electrical  engineers. 

I was trying to keep it as simple as possible and us lay terms to avoid confusion.  An inverter is a discrete component within an UPS, may consist of other components (like batteries and distribution units).  An UPS doesn't have to have an inverter.   But I think this is getting into the weeds, unless my functional description (not necessarily the exact nomenclature terms) is flawed. 

 - Rick N.

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Your description was clear Rick.The battery bank plus the inverter would constitute the typical description of a dc/ac  UPS. Just nomenclature. I sometimes wonder if people appreciate how dangerous it can be if they step from the RV and become the ground path for whatever reason.

 

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6 hours ago, waterskier_1 said:

Your inspector is wrong.  There can be only ONE point where the neutral and ground are bonded, and that is at the source.  For shore power, that would at the transformer (large campground) or the Main Poker panel (at your house or wherever the power come in).  The coaches power panel is similar to a Sub Panel in the NEC.  Therefore the neutral and ground must he separate to the main panel.  No for the "gotcha".  When you disconnect shore power, you also disconnect the ground from the coach.  But we can still have 110 VAC from the inverter.   This I'd handled by (in most cases) the inverter internal transfer switch - not to be confused with the large generator transfer switch.  When the inverter senses loss of incoming 110VAC, it initiates a transfer to the inverter circuit, powered by the battery.  It switched the incoming 110VAC from the main circuit breaker panel to the inverter power, and it continues out the inverter powering the microwave and outlets that were powered by shore power.  At the same time it bonds the ground or neutral together inside the inverter box.  The inverter is now the main source of power, and now the neutral and ground are bonded there.   The only time the neutral and ground should be bonded together in a coach is when no other source of 110VAC is available.  The inverter can not tell where the input 110VAC is coming from so it will not bond the two on the generator.  That is why the generator, when running, is now the main source of 110VAC power, and it will provide the bond between the neutral and ground. 

Hope this helps,  post any questions I didn't address.

   - Rick N.

Rick, Thank you for your quick response. I was not so clear and precise about the how the actual tests were performed on the two power panels. The continuity tests were done with no shore power with the shore cable unplugged from its source, no generator power and no Inverter power. Basically completely dead electrical panels.

Main panel had no continuity, inverter power panel had continuity and now I understand why. It is basically wired to be the same as the Onan Generator with having the neutral and ground bonded as it is a power source. 

Thank you so much for clearing that up as it makes total sense to me now when I stop and think straight about the situation.

3 hours ago, Gary Cole said:

Your description was clear Rick.The battery bank plus the inverter would constitute the typical description of a dc/ac  UPS. Just nomenclature. I sometimes wonder if people appreciate how dangerous it can be if they step from the RV and become the ground path for whatever reason.

Gary, that is called a "Hot Skin" condition. People have died from that very situation as I remember sometime ago it happened to a very young child who had come back from swimming and attempted to enter the RV.

I carry a small pen like device to test the side of the coach and even other RVer's in the neighborhood if I suspect there could be a problem.

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Every panel i have ever seen they are both connected through the panel. The neutral on shore ele is the stand & the ground is the chassis. With the gen running both are chassis bound. 

If you Google it, its right. As a practical matter, if he dosent know this does he know water flows down hill.

A good licensed electrician would be better in this case. 

 

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Hi Rick, so is Nevada Rob's solution when plugging into an external portable generator the recommended solution? One of our sons asked me about that the other day when he discovered he had an open ground when plugged into his generator. He said that he was using a "generic meter so it may have been an open neutral."

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10 hours ago, Gary Cole said:

Your description was clear Rick.The battery bank plus the inverter would constitute the typical description of a dc/ac  UPS. Just nomenclature. I sometimes wonder if people appreciate how dangerous it can be if they step from the RV and become the ground path for whatever reason.

 

As is the possibility when you visit another RVer in the camp whose not grounded properly. 

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2 hours ago, Jim McGarvie said:

Hi Rick, so is Nevada Rob's solution when plugging into an external portable generator the recommended solution? One of our sons asked me about that the other day when he discovered he had an open ground when plugged into his generator. He said that he was using a "generic meter so it may have been an open neutral."

This is a solution if the generator is not "bonded".  I HSBC little experience using portable generators to power coaches, but I've read several articles where people imply the same solution as Nevada Rob's.  If you are using the portable generator to power portable tools and lights, it doesn't really matter. 

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I don't want to get into a side discussion and highjack Dr4Film's aka Richard's original post and question. He asked a very good question and I wish I knew this before going half crazy with my backup generator not working. With regards to a non bonded ground generator, the inverter style i.e. Honda, Yamaha etc. will need a tweak. A regular Coleman or other construction site use type generator will most likely work without a jumper plug. We dry camp 95% of the time in the middle of nowhere. My wife uses electrical appliances like a kid in a candy store. I use the Honda to power the crockpot, TV, vacuum cleaner, refer, DVD player and everything else that seems to be on all day. I am the exterior operations manager. I don't get involved in interior operations. It is safer and more peaceful that way.

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I don't know anything about inverter generators. However I wonder if they use a high resistance ground system which would serve to protect the generator from a fault. If so the system would need to see a path between the neutral and grounded equipment conductor.

 

 

 

Edited by Gary Cole
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For those following this thread in regards to portable generators here is what Southwire Surge Guard offers to resolve the bonding issue.

"Surge Guard* Generator Neutral-Ground Bonding Plug Model 44400
Most portable generators have a floating neutral. Surge Guard* products will detect this as an open ground condition and not allow power to pass through. To solve this problem, insert the Surge Guard Generator Neutral-Ground Bonding Plug into a 15A receptacle on the generator control panel. This will create a neutral-to-ground bond and the open ground condition should be resolved. Please check the owner’s manual of the generator to ensure the generator was designed with a floating neutral."

  

Bonding Plug.png

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Richard is right on the money with the Surge Guard plug. The GFI will trip on the receptacle the the device is plugged into. At least mine does. I made my plug up for about $6 from supplies at Home Depot.

A question for Dr4Film, how is the rest of the potential new coach and will you be the new proud owner????

 

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19 minutes ago, Nevada Rob said:

A question for Dr4Film, how is the rest of the potential new coach and will you be the new proud owner????

I consider it a "done deal". There were 5 key items on the inspection report that needed attention.  The owner & or dealership have agreed to take care of 4 of them. There were a number of minor problems which is totally expected of a 15 year old coach that has had 3 different owners and now 4. But all of those are readily repairable by myself. The major concerns were the following:  In the Inverter Powered Circuit Breaker Panel, there were supposed to be two GFI circuit breakers but they had been replaced with regular type circuit breakers. That is a Life Safety Issue! The others were - fresh water hose reel inoperative, water pump running continuously, broken ice maker, and the Induction Cool-top was inoperative.

Should have the coach back to Florida late February or early March. Prepping the Windsor now to advertise it hopefully in January sometime.

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Here is a photo of the coach when it was taken out for its test drive. A service tech from the dealership drove and the inspector rode along.

It was also a good time to test the Girard Patio Awning. The location where it was parked at the dealership didn't allow for extending the awning.

I will post more photos in a new separate thread.

IMG_2077.jpg

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Congratulations and I truly hope you have many great memories and trouble free miles in your new coach. That is a good looking machine.. The awning on my Dynasty is 110 volts drive motor. We figured it was broke when I bought it because it did not work. We finally figured out that either be plugged in or inverter on for it to work.

 

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1 hour ago, Ray Davis said:

Oh boy Richaed that coach is bea-u-ti-ful.  I'm getting a little jealous, I love our 03 Windsor, but I could love a Dynasty too, probably even more.

Isn't that snow?  It's not from around here, It's like 80 deg for Christmas here in Tx.

Ray, it is currently located in Salt Lake City, Utah.

13 minutes ago, Chargerman said:

Very nice Coach Richard.  Happy for you guys. Based on your posts previously   I didn’t think a Coach update was in your future. Best of luck with it and let the “Richard” touch begin. 

After spending over 2 months going through multiple coaches looking for the "right" Dynasty but finding mostly junk that was over priced and in worse shape than my 2002 Windsor, I almost gave up looking. It made more sense to keep what I had versus buying something that needed a lot of work and upgrading. But then this Coach came along and the owners were highly motivated to sell. Plus it was exactly what I had been looking for with regards to exterior and interior color scheme, floor-plan and condition.

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