50 amp neutral question

[glenn allen]

NEC 2011
Article 551, Recreational Vehicles and Recreational Vehicle Parks
551.56 Bonding of Non-current Carrying Metal Parts

You might notice the miminum size for the bonding conductor is 8 AGW copper.

[glenn allen]

Oh, sorry the distribution panel of your Onan is the space where the genset breakers or other overload devices are located.

You may want to up-date your education credits in grounding and bonding.

Another point, you are incorrect in the size requirement. anything mounted in a recreational vehicle is the subject of NEC Article 551

Scope of Article 551

"The provisions of this article cover the electrical conductors and equiptment other than low voltage and automotive vehicle circuits or extensions thereof, installed within or on vehicles, the conductors that connect recreational vehicles to a supply of electricity, and the installation of equiptment and devices related to electrical installations within recreational vehicle parks."

if you would send me $60.00 USD and some extra for the shipping along with an address I will send you a copy of the 2011 code.

You might also want to hunt down NFPA 1192-2008 Standard on Recreational Vehicles

and

ANSI/RVIA 12v-2005 Standard for Low Voltage Systems in Conversion and Recreational Vehicles

So, now you have three authorities. None of which agree with your position.

[Dr4Film]

Here is some information from Cummins/Onan about generator bonding/grounding.

http://cumminspower.com/www/literatu...ingAC-1-en.pdf

http://www.cumminspower.com/www/lite...ingAC-2-en.pdf

And here is an article written by a blogger.

Generator bonding and grounding

Dr4Film ----- Richard

[Dave78Chief]

Dwayne,
Getting back to your original question about neutral bonding, here is a page from the Onan HGJ Series Installation manual (983-0600B).



You will notice that the neutral (white) and ground (green) leads are connected together "inside" the generator for either a 50 amp or 30 amp setup. If you do not also "switch" the neutral lead in a transfer switch then the neutral and ground leads will be "bonded" together via the generator. This same problem occurs with inverters also. By code, when connected to shore power, the RV shall not have the nuetral and ground leads connected together in the RV therefore, due to the connection inside the generator, the nuetral lead must also be switched. This ensures the only neutral / ground connection is at the "source" whether that is the shore power supply or the generator. This is a typical connection setup for an RV.

Dave

[bruceisla]

Thanks all .... good reading ..... some stuff to think about!

[Tallyrver]

On our last coach ,there was a strong burning smell coming from the power compartment area, I found the plastic cover on the transfer switch melted.
Notice the neutral wire . All the screws were loose. Had to replace the switch. I checked the screws on our new Winnie,I found a couple loose also.

I have made it a part of the annual walk thru to check connections in the electric panel and transfer switch.

Wayne

[RVBaby]

Excuse my ignorance, just trying to learn and understand....what is "bonding the neutral and ground" actually mean.

[teddyu]

I'll try to sum it up. Its a safety thing that is mandated by the National Electric Code. A house is wired similarly.

A simplistic way to describe the NEC requirement is that the neutral and ground wires should be "bonded" (connected together) at ONE POINT AND ONLY ONE POINT, that is at the "source" (any separately derived system). In order to ensure code compliance, the neutral and ground wiring in the RV distribution system are required to be isolated since the distribution panel is considered a sub-panel to a “source” per NEC parlance. To ensure adequate protection:
(1) Shore power should be bonded (N-G) prior to the receptacle at the pedestal;
(2) the onboard generator should be bonded (N-G) to the RV chassis (551.30A) prior to the shore power – automatic, or manual generator transfer switch or receptacle (if equipped) that effectively isolates the bond from the breaker panel unless the generator is providing AC power;
(3) an inverter should be bonded (N-G) prior to the inverter’s transfer switch, if equipped; if the inverter a pass through style, it should be wired (thus bonded) per the vendor’s instructions; and
(4) a portable generator requires bonding per the system configuration. Most generator manufacturers do not bond the generator neutral and ground but have a separate capability of bonding the neutral and ground within the generator (not the generator enclosure). The non-bonded generator has what is known as a “floating neutral”. When portable generators are sold to home owners for use as an emergency power source for the home, the generator usually are connected to the house main breaker panel. That panel is bonded by the NEC requirements therefore it would be a code violation for the generator to also be bonded. When used as a stand-alone (not installed to the house main breaker panel) power source, portable generator’s neutral and ground require bonding to ensure proper protection, therefore most manufacture’s provide the capability for bonding the neutral and ground by physical connection (strap/cable) or switch. Hope that this wasn't to much to take in at one time. JM2¢...

[RVBaby]

Thank you for your explanation, even if it is still "Greek" to me I will at least know enough to have my dealer show me and explain it all to me. Once I get a visual with the explanation I should be wiser! Thanks again!

[dwaynedmonnett]

Well, I finally got to the ground level on this problem. I checked my transfer switch, even broke the NEC rule by jumping over the neutral contacts to make sure it was either in the transfer switch or not. I continued to have voltage issues. Next I used my 30 Amp adapter to connect up. No more high voltage issues, however the MW would pull the line voltage low to about 106 V intermittently. Now is when an old analog VM would have been of great help. The digital ones just take too long to sample and display a reading. I even used the standard 20 A duplex outlet with a new 20 Amp extension cord for a test on the MW. The MW is routed thru the inverter so I wanted to rule out the inverter as a problem. Well, it would still attempt to gag when used. Next step was to have the park electrician come and check the power pole. He was knowledgeable and did pull the panel apart first. Yes, it was in the park power box problem. The neutral connection was all arced up. It had been bad for some time. As it was common to all three outlets in the panel, all of my tests showed similar results, and almost led to a conclusion that the problem was mine. A new connector and panel solved the problem. Saved me from having to purchase a new transfer switch.

Dwayne

[Dr4Film]

Dwayne,

Pleased to hear that your Neutral issue has been found and corrected.

Now go back to post #3 and heed his warning. It will be one of the BEST investments for your coach.

The Progressive Industries EMS system is one of the best electrical protection devices available. When this problem first reared it's head, the EMS system would have identified it immediately and it would have protected all of your electrical devices inside the coach including all humans.

EMS-HW50C

There are places to purchase this for a little over $300.

Dr4Film ----- Richard