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Kirk W

Portable inverter/generators?

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Travel Trailer, and all others:

  Thanks a lot for the post, fun discussion going on. At one time when I was practicing power distribution engineering design and attending Mike Holts or Joe Mc Partlands NEC seminars, I was pretty sharp and current on this, but rusty now so like others here, I ALSO  DO NOT claim to be an expert. 

  SO BELOW IS INFO FROM EXPERTS SO TAKE THEIR WORD FOR IT NOT MINE

 Sure one can find "seemingly" conflicting opinions and I maintain my position there are times when its proper to bond and times it’s not, BUT the differences can be a bit tricky, so let me do as you did and post a few quotes from OSHA and other reliable sources IE “Experts” ????

 

FROM FOR CONSTRUCTION PROS

Generators used on construction sites supplying cord-and-plug connected equipment (tools, lights, etc.) are considered a “separately derived system” in the National Electrical Code and thus, the neutral must be bonded to the frame of the generator.

In some cases standby generators are not required to have an electrical bond from the neutral to the frame. Such so-called "floating neutral generator" applications occur when connecting to a recreational vehicle and connecting to home power where the transfer switch does not switch out the neutral to ground connection

HMMMMMMMMM this seems to say a floating genset is okay for powering an RV

 

FROM NO SHOCK ZONE

Contractor-type generators such as your Coleman 5000 are generally G-N bonded internally, which is why it runs your RV just fine. However, many portable inverter generators from companies such as Yamaha and Honda (your EU3000 specifically) have floated Neutrals (no internal Ground-Neutral Bond) since they expect an external G-N bond to happen somewhere else. And while RV-approved generators may have an internal G-N bond, it seems that many of the most popular portable inverter generators from Honda and Yamaha have floating neutrals.  Now I discussed this very point with Honda engineering , and they confirmed that their inverter generators have floated Neutrals and simply say that you should follow all local electrical codes for bonding-grounding. So your EU3000 isn’t providing the Ground-Neutral Bond that your RV requires to think it’s getting properly grounded power, while your Coleman 5000 has a Ground-Neutral bond already so it operates your RV properly. Seems crazy, but that appears to be the scenario.

It’s pretty simple to wire a special “Ground-Neutral Bond” jumper cable for your Honda or Yamaha generator which will allow you to power your RV through its voltage protection device. You can obtain or make a dummy 15 or 20 amp “Edison” plug with the Neutral (white) and Ground (green) screws jump together with a piece of 12 or 14 gauge wire (see photos below). This G-N jumper plug can be plugged into one of the generator’s unused 20-amp outlets, and the entire generator’s electrical system will be N-G bonded. You can then use the other 20-amp Edison outlet or the 30-amp outlet to power the RV.

So this is a generator-only G-N bonding plug which should be only plugged into a portable generator while powering your RV.

HMMMMMMMMM this seems to say a bonded NON Floating genset is  for powering an RV, BUT it may have more to do with allowing an EMS system to still work which would NOT if the Neutral were floated.

 

FROM OSHA FACT SHEET GROUNDING REQUIREMENTS FOR PORTABLE GENERATORS

Now’s where it gets more complicated lol

 

Grounding Requirements for Portable

and Vehicle-mounted Generators

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):

The generator supplies only equipment mounted on the generator and/or cord and

plug-connected equipment through receptacles mounted on the generator,

§ 1926.404(f)(3)(i)(A), and

The noncurrent-carrying metal parts of equipment (such as the fuel tank, the internal

combustion engine, and the generator’s housing) are bonded to the generator

frame, and the equipment grounding conductor terminals (of the power receptacles

that are a part of [mounted on] the generator) are bonded to the generator frame,

§ 1926.404(f)(3)(i)(B).

 

 Thus, rather than connect to a grounding electrode system, such as a driven ground

rod, the generator’s frame replaces the grounding electrode. If these conditions do not exist, then a grounding electrode, such as a ground rod, is required. If the portable generator is providing electric power to a structure by connection via a transfer switch to a structure (home, office, shop, trailer, or similar) it must be connected to a grounding electrode system, such as a driven ground rod.

 

 

 

NOW MY OWN OPINIONS AND EXPLANATION BEING A LONGGGGGGGGGGG RETIRED ELECTRICAL POWER DISTRIBUTION DESIGN ENGINEER No Expert, No Warranty

 

 

 1) For starters, NOTE (mostly from the more complex OSHA quotes) the subtle difference when the frame of a portable genset can be substituted and used for the GROUND versus when there needs to be a driven into the earth Ground Rod  !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

2) Also note the previous OSHA article I linked which describes how on construction sites driving an earth ground rod IS HAZARDOUS !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

 

3) FYI Differences based on Transfer Switch/Method used

     a) In cases where the Transfer Switch  DOES NOT switch

         the Neutral. The portable genset MUST HAVE  A

         FLOATING NEUTRAL and its case frame bonds to the

         Equipment Ground Buss IE Only ONE NG Bond

      B) In cases where the transfer switch or plug and cord

           DOES SWITCH THE NEUTRAL iffffffffff you still want a

           Bonded versus a Floating system, there needs to be

           a Neutral Ground Bond in the genset.

 

4) ALTERNATIVE: Sure you could still create a Non Floating Neutral Ground Bonded system by Bonding the Gensets Neutral to Case/Frame but NOTTTTTTT drive a Ground rod and effectively still keep it isolated with respect to "mother earth" and that would work and satisfy an EMS sounds cool right ?????????????   HOWEVER that sounds to me like the NEC's "Separate Derived System" which requires a grounding electrode (like a driven rod and frame alone does NOT satisfy) whereby its NOT earth isolated so a hot skin with respect to earth could still cause a shock   SEE WHY I WARNED YALL IT GETS COMPLICATED ????? If earth isolated but still a NG Bond and the RV and EMS all work fine "sounds safer" to me  BUT THAT EARTH ISOLATION (Frame but NOT driven rod serving as Ground) doesn't appear to meet the NEC standards and those standards are for a good reason ya know !!! STILL EVEN WITH A GROUND ROD and a NG Bond, that's NO different then in an RV park and that's where you are typically anyway SO NO BIG DEAL right ??

  

 

FINAL THOUGHTS

 

 Kirk asked his great question and very specifically sought input from those of us with "electrical design backgrounds" he said which I have tried my best to comply with and put forth a ton of time and effort for which I’m happy to do, as he and Jack and Yarome and Stanley and Lou and Dutch and so many others here have helped me in the past, so it’s my pleasure to answer their questions to help and repay them.

 

HOWEVER it’s impossible to describe here on a Forum what can takes years of study and entire library volumes so I doubt all non sparkies will comprehend this, heck it’s tough for me an electrical engineer lol

 

THAT BEING SAID sure the Honda will work and power an RV as designed with a Floating Neutral. Loads operate if there’s 120 VAC from Line to Neutral and don’t know or care if there’s any Neutral Ground Bond or any connection to mother earth or not HOWEVER it can drive an EMS nuts which creating a bond will cure.

 

SAFETY DIFFERENCES

 

 If you have a genset powering the RV with a Neutral Ground Bond (NON Floating) and ifffffffffffff the Neutral is bonded to a driven into the earth Ground Rod (NOT just the frame substituted as Ground as OSHA permits on construction sites) and if your barefoot on wet ground grandchild touches an RV which for some reason ends up with a Hot Skin HE CAN BE ELECTROCUTED. BUTTTTTTT that is no difference then at an RV parky anyway  !!!!!!  

 

HOWEVER

 

 If the RV is fed by a Floating Generator and somehow a hot wire gets against the skin and your grandchild touches it HE IS NOT ELECTROCUTED and the RV (other then EMS) still works.

 

NOTE Sure there can be GFCI and other protection to prevent hot skin in the first place, but they can fail !!!!!!!!!!!!  and if they do a floating system can be safer in certain conditions, not all.

 

 

 

 

AT THE RISK OF ONE FINAL PERHAPS  OVER SIMPLIFICATION

 

 a) If you do create the NG Bond, its my reading of the NEC (not talkin OSHS here mind you) you should drive an earth ground rod HOWEVER it will still work PLUS the EMS will work BUT its still not NEC proper (Separate Derived Source needs proper Ground)....even though its done like 99% of the time lol

 

B) If you leave it Floating, it will still work BUT NOT THE EMS and it can be a bit safer since there's no voltage on the hot with respect to mother earth !!!!!!!!!!!!!!! IE you touch a live hot wire barefooted and get no shock  Ya know that sounds like a GOOD thing !!!!!!!!!!!!  

 

 

 

 ITS YOUR LIFE AND RISK AND YOUR CHOICE TO USE A FLOATING VERSUS A BONDED GENERATOR. I tried my best to comply with and answer Kirks great question, I sure hope this wasn't all, in vain grrrrrrrrrrrr lol

 

 Best wishes and thanks to all here and all who contributed and God Bless all of you, I gave it my best shot !!!!

 

John T   BSEE, Purdue University,  JD Indiana University School of Law, Long retired and rusty Power Distribution Design Engineer

 

PS if the genset is Floating and the RV iron frame is also Floating, bonding those two hunks of iron together DOES NOT create a Neutral Ground BOND, its still Floating !!!!!!!!

 

PS if anyone disagrees or takes issue with this, don't flame on me, take it up with OSHA or The No Shock Zone, its THEIR NOT MY information posted above......  

 

PS Sure OSHA has to do with workplace safety and construction versus RV's STILL these some good info and helpful electrical theory in their publications to help non sparkies understand all this.... 

 

Kirk you rascal lol its YOU who opened this can of worms, dont blame meeeeeeeeeeeeee I hope to take you up someday on your invitation to visit....... 

Edited by oldjohnt

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7 hours ago, oldjohnt said:

Kirk you rascal lol its YOU who opened this can of worms, dont blame meeeeeeeeeeeeee I hope to take you up someday on your invitation to visit....... 

I am still thinking that I'll build my own bonding device much like the one that Jack has on his site, but I will do it in a box that connects between the Honda and my TRC with a built-in GFCI. I'm still hoping that Randy will leave the HDT club long enough to participate in this discussion as he very clearly has put a great deal of work into his reviews and I can well see why Jack so highly recommends him. GFCI is clearly a good idea for this situation.TRC even makes a device that might work for this situation. I think that I could make one for less cost.

                                                          25080%20011-6.jpg&height=400&Compression

Edited by Kirk Wood

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2 hours ago, Kirk Wood said:

GFCI is clearly a good idea for this situation

That's right Kirk, if you want to create your own Neutral Ground Bond in that otherwise Floating Honda, making it essentially like if you were in an RV park:  1)  The RV will function fine,,,,,,,,,,,,,2) Any EMS and Sensors or Monitors will be okay  3) GFCI will provide shock protection and reduce any hot skin problems (besides GFCI is already a necessity in outdoor and some other applications). There can still be some safety advantages in an isolated system like Lou and I discussed which is ONE (among others) of the reasons I described why Honda and others Float the Neutrals. They can't know if you're backfeeding a home,,,,,,,,,,,,, or powering an RV,,,,,,,,,,,,,,,,,, or using a transfer switch,,,,,,,,,,,,,,,,,,, and if so if you switch the Neutral or not,,,,,,,,,,,,,,,,so they (lawyers and engineers  I bet lol) choose a possibly  SAFER isolated system  AND TELL YOU TO GROUND PER THE NEC TO COVER THEIR A$$  LOL     But creating a NG Bond as you propose  will work fine. There may still be some proper "Grounding Electrode" NEC "Separate Derived Source" issues left unresolved, BUT IM NOT GOING THERE NOW AT LEAST I'm tireddddddddddddddd.  

CONGRATULATIONS YOU SURE ASKED A GOOD QUESTION,,,,,,,,,,,, THERE FOLLOWED AN INFORMATIVE DISCUSSION,,,,,,,,,,,,, YOUR QUESTION GOT ANSWERED,,,,,,,,,,,,,,YOUR DECISION IS SOUND,,,,,,,,,,,,,,,,,,

NOTE There is of course to be ONLY one Neutral Ground Bond (Single Point Grounding) and its typically created at/near the energy source.  MY PREFERENCE would be to Bond at the Generator. Downstream devices and sensors, monitors or EMS etc. should all function fine, but as long as the bond is BEFORE them, all should still work okay. I would prefer a HARD WIRED Bond versus the light duty jumpered plug method spoke of earlier, even though sure it "works"

I think you got your answer and we pretty well beat this old horse to death. I'm happy I was able to help you for a change.

John T    Previously a Half Timer of 10 years, now to be a Full Timer as we sold our farm and are moving into the RV and are currently HOMELESS until we may buy a small place (home base) next spring

 

Edited by oldjohnt

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6 hours ago, J-T said:

Why not swap the main beaker for a GFCI so everything is protected no matter where the power is coming from?

That's a valid question JT. One thing to consider is a GFCI ONLY protects what's downstream of it but NOT what's coming to it. I suspect when Kirk posted that pic of an in line GFCI he was concerned with providing GFCI protection in the cord and supply TO his RV as a soft rubber most vulnerable RV cord is what's laying perhaps in water or on sharp rocks and getting ran over etc. and  my always worrisome barefooted little grandchild stepping on it or the dog chewing it  ??? Another thing to consider is GFCI breakers are typically used on INDIVIDUAL 120 Volt BRANCH CIRCUITS (NOT the Main) to insure all (or within 5/6 milliamps)  the current flowing OUT the Hot UNgrounded Conductor (in that one circuit)  is returned back IN by the Neutral Grounded Conductor, NOT via any fault.  Another, if you GFCI'd several branch circuits and each of 5 leaked a measely  0.001 amp each THERES A NUISANCE TRIP.  Another, a 30 amp RV has a  120 volt SINGLE POLE MAIN  breaker, while a 50 amp is 240 volt and has a TWO POLE main breaker, but you already knew that....  

 You will have to ask our friend Kirk about his use of that inline device, this is only my guess.

 Since he has decided to go with a Bonded versus a Floating Generator system, GFCI sounds okay in my opinion, even though its (grounded not isolated) no different then if he were in an RV park.

 

John T

Edited by oldjohnt

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FWIW, my Boliy PRO3600IS  inverter genset also has a floating neutral. I have to use that home-made bonding plug to power our MH. It would power our 5er without the bonding plug, but that 5er did not have an EMS.

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12 hours ago, Ray,IN said:

I have to use that home-made bonding plug to power our MH. It would power our 5er without the bonding plug, but that 5er did not have an EMS

Good Morning neighbor, I hoped to see you before we head out FULL TIMING as we sold our farm, but time is growing short.  Indeed the simple short n sweet home made grounding plug creates a BONDED Neutral which could allow an EMS or similar system to function.

   To summarize this informative thread:

   1) A FLOATING Neutral (as are many small isolated gensets) powers up loads and "often" all works fine and can be safer with respect to coming in contact with a hot wire while standing on bare earth, but an EMS or other such monitors and protective devices not seeing a Bonded Neutral can "alarm"

  2) In the event you choose to BOND the Neutral, the NEC (as best I read it but no warranty) when configured as a "Separately Derived Source" requires connection to a "Grounding Electrode" (earth and/or several other suitable electrodes) and while OSHA allows the gensets frame ALONE to serve as a substitute "Grounding Electrode"  that's for construction work sites where portable plug and cord tools must be plugged into onboard receptacles, but that's not really RV use !!!! PS having owned an RV for 47+ continuous years and a past dealer, I've ONLY seen a few who actually drove a ground rod to connect to a small portable bonded genset IE it obviously still works without it WELL DUH LOL. But the manufacturers cover their A$$ by citing "GROUND PER THE NEC"

 Best wishes and God Bless  all here

John T    

Edited by oldjohnt

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OK, one simple question.

SET up, My Yamaha YM6500DE generator is shock mounted on the flatbed  of my Tow vehicle. Normal drill is: I plug in the shore power cord into my RUNNING genset and close the breakers (120 VAC) to power up the 5th wheel for AC and such when boondocking. Shutdown is: Open the breakers, cool down, shut down, stow shore power cable.

There is a wing nut  terminal on the genset frame marked GROUND.

Here comes the question.

What is accomplished if I drive a short, ~ 2 foot, ground rod into the dirt and wire it to the ground terminal on the genset.,  Will it  protect  my electrical system in the 5'er, or am I just spinning my wheels in the muck of misunderstanding?

Thanks, Shooter

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I just purchased the champion dual fuel generator. No need to carry gasoline anymore. Sits in truck bed on a rubber mat. This unit is very quiet. Tractor supply sells a 3/4" rubber mat used in horse stalls. $35.

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7 hours ago, shooter51 said:

what about the landing gear jacks and 2 sets of stab jacks in direct earth contact ?

But your RV does not have an earth ground either. Only the 12V system uses chassis ground. Your RV is wired just like an appliance with all of the ground tied into the ground wire of the power cord and the neutral & ground busses are not bonded together. It then ties back to the power pedestal for earth ground. In addition, the jacks sitting on the ground provide very little connection to earth ground unless it happens that they are sitting in very wet conditions. The reason electrical codes require a long ground rod driven deep into the earth is that in dry conditions the length is needed and the rod reaches far enough down to where the soil is always damp. 

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All right then, My power set up, crude as it is , Is safe enough, in both concept and practice, that the CEO and I can both get older and cranky'er in our relatively safe travel accommodations, with no changes to the method's that might invite madness.

 

Thanks all, for the learned input.

Shooter 

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On ‎9‎/‎24‎/‎2017 at 9:57 AM, Jack Mayer said:

Remember, the NEC is not always the "best" answer. It is always (or almost always) a "sufficient" answer.

 

Jack, I can recall some of my lay person "opinions" of the NEC   BEFORE  I studied it thoroughly   BEFORE   I worked with it nearly my whole career in electrical power distribution  BEFORE  I attended NEC educational seminars taught by experts such as Mike Holt or Joe McPartland (NEC board members as I recall)  and obviously those opinions changed (and were corrected) drastically LOL.  I learned many sections a lay person might find confusing (or lacks any understanding of whatsoever) came about due to a fire or an electrocution AND MADE GOOD ELECTRICAL SENSE. In my career and education and  experience working with the NEC I found it to be quite good and sufficient, even if not 100% perfect. 

  NOTE IM NOT SAYING ITS 100% PERFECT AND COMPLETE ( but who of us is qualified to say ???) but if a person chooses to ignore it or thinks he has a better way and knows more then the NEC panel of experts DO SO AT YOUR OWN RISK is all I have to say. I trust it MORE then what a less experienced or educated  person may think BUT WOULD NOT FOLLOW IT BLINDLY EITHER. I believe in using good judgment and safety as some of the NEC merely specifies certain MINIMUM   requirements and there's no harm in going one step further and safer IF YOU ARE WILLING TO BET YOUR LIFE on what you think??? To each their own methods and opinions and choices when it comes to life safety, I support their free choices and expect the same in return.

  Kirk started all this with a great question, and one bottom line thought is there's a reason and a place for having  a Floating Neutral and a reason and a place for a Bonded Neutral. In RV use and if energy management devices are used it's often a Bonded Neutral that works out best

 Thanks for the post, fun chatting with you Jack and others, hope this helps.

 God Bless, Happy Easter to all, He is risen.

John T  Long retired EE and rusty on the latest codes SO NO WARRANTY do as yall wish is fine by me, follow codes or ignore them if you know better, but no harm in being EVEN SAFER then some "minimum" NEC requirements either

Edited by oldjohnt

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8 hours ago, hemsteadc said:

Than, the word is than, as in safer than, or other than.  Thank you.

And THANK YOU for the correction, I appreciate it. Like many nerdy engineers and technicians English or Typing skills ARE NOT MY STRONG SUITS LOL.

Best wishes, God Bless, Happy Easter

John T

 

Edited by oldjohnt

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