1965 Caravel Electrical System upgrade...need help please.

[markdoane]

The only comment I have is that the shell may be bonded to the ground for the 120V service, rather than the steel rame.

There is a specific exception for this in NEC 551.56 (B), where unitized metal body RV (Airstreams, Avions, etc) use the body rather than the steel frame.

[VIKING]

Originally Posted by Ronald D

Jammer, I believe that you have it just right. The only reason I got in on this thread was because of Rich the Viking post #4 when he said to NOT GROUND THE CHASSIS.

John, you are also right, your son is paying attention in his classes. The Airstream is treated just like a stove except it is 110 instead of 220, three wires instead of four. The frame is grounded and that ground is NOT connected to the neutral inside the stove. An electrical panel has two buss bars inside, one for the neutral (isolated from the enclosure) and one for the ground which is bonded to the enclosure) The grounding buss is then bonded to the chassis. You say that you're concerned about some of the trailers out there, after seeing post #4, so was I. I hadn't read 551-20 for 40 years, thanks for that information as I knew nothing about 12 volt wiring. All my questions have been answered, especially by Jammer when he says the 12 volt wiring is a 2 wire system, unlike a car that uses the chassis for a return.
Thanks to all, this is my last post ever on this site, I asked what I thought was a simple question and I was met with derision in some quarters. John and Jammer are tops, even Rich the Viking is ok, he was just repeating what someone told him. When he realized his information might be incorrect he asked for clarification. I am now going back into retirement to work on my Overlander, never to look at this site again.

Retired Ron

Sorry to hear you are not coming back Ronald D. I find that you have to be rather thick-skinned to put up with some of things put forth here, as you have experienced. I try to keep my experience positive by reading a lot more than I post. The old information on this site is way more valuable than the new in most cases, exceptions being for things that are actually changing and improving, such as hitching, lighting, heating and a few others.
Since you state that the above was your last post I will send this as a pm also, in the hope that you will continue to use this resource to your benefit. As you stated, there are some good folks here, and your interaction with us is appreciated. Also, keep in mind that there is a private message system where you can contact any individual and ask for, and give help or guidance without having to expose yourself to the whole community.

After re-reading my post #4 I find that I was so incomplete as to be incorrect. Sorry for the gibberish, I know better than what I wrote there.
To explain my situation: I had no ground wire going to the chassis in my safari at all. the grounds all tied together at the buss bar and the enclosure was attached to a wood post rather than the metal chassis. I'm not stating that this is a correct set-up, just what I actually found in my safari. I also opened up every electrical connection in my rig and nothing anywhere on the 110 circuits was grounded to the chassis. I purchased a progressive dynamics power control center and in the installation instructions it doesn't say to ground the control center to the chassis and it doesn't show a ground indication other than the ground wire coming in with the shore power. In a previous thread I read that some convertors are grounded and some are not, and that, along with the instructions, lead me to believe I had one that did not require it. Then, in an earlier reply to this thread Inland Andy stated that you do need to ground the convertor to the chassis. After reading through some old threads on this I see that there is way more confusion with regards to this than I was experiencing myself, and the fact that master electricians are questioning the correct set-up make me feel like I'm in the right company, anyway. Now I'm in contact with Progressive Dynamics to see what they have to say. As stated before, this is too important to not get it right.

Rich the Viking

[Inland RV Center, In]

Originally Posted by VIKING

Then, in an earlier reply to this thread Inland Andy stated that you do need to ground the convertor to the chassis.

Rich the Viking

It is not necessary to ground the converter to a ground, but you can if you wish.

You "MUST" however, ground the negative wire from the converter, or nothing will work, since the negative wire, is the return circuit for the all the 12 volt DC circuits.

Think of the trailer 12 volt system as being the same as a car or truck, as far as how things work on DC.

Andy

[markdoane]

Originally Posted by Inland RV Center, In

It is not necessary to ground the converter to a ground, but you can if you wish.
.......
Andy

It's not necessary, but it is required by NFPA/NEC.

Don't know why this keeps coming up.

[VIKING]

Originally Posted by markdoane

It's not necessary, but it is required by NFPA/NEC.

Don't know why this keeps coming up.

Thanks, Mark. As I stated above, The actual instructions with the unit I purchased do not indicate a grounding of the unit to the chassis. If the manufacturer doesn't even address the issue of grounding it obviously raises some questions, and I am no electrician, as you hopefully have discerned by my lame attempts at trying to help someone do something that I don't know well enough myself to advise on. I read through several threads on this but there is varying information and conclusions in them. See the first paragraph in the first post of this thread http://www.airforums.com/forums/f449...ter-56389.html
misinformation still abounds, hence the need for clarification.
Thanks again,
Rich the Viking

[Inland RV Center, In]

Originally Posted by markdoane

It's not necessary, but it is required by NFPA/NEC.

Don't know why this keeps coming up.

Mark

Could you please post that info, or e-mail it to me.

Thanks.

Andy

[markdoane]

Andy,

Ronald D in post #15 has the correct section. It's 551.20 (C).

The 2008 edition of NEC is available in open format, you need to go to NFPA and register or sign in to view it. Doesn't cost anything. However you can't copy, save, or print it.

It's on page 480.

[Jammer]

Originally Posted by Inland RV Center, In

Ron.

All Airstream and Argosy products use a "one wire 12 volt system" and use the chassis and/or shell as the ground return.

Andy,

Is this true for the higher current connections as well? One might hope that the converter output, at least, would have the negative side wired straight to the battery bank. Same for an inverter if present. I'm not an expert on Airstreams but I've seen other RVs wired this way --- the chassis return is only used for small, distributed loads.