My Interstate Lithium Battery Adventures

[73shark]

Lucky you. We're headed for -6F tonite.

[InterBlog]

Originally Posted by 73shark

Lucky you. We're headed for -6F tonite.

Our luck ran out Sunday morning when a Blue Norther dropped our temps 40 degrees in a matter of hours (typical for Houston this time of year - we call it "whiplash weather").

We are replacing as much of the wiring as possible with better-quality marine wiring and also as a means of un-doing the Airstream-inflicted rat's nest under the closet floor where the lithium battery bank has to go.

Yesterday afternoon we had every intention of pulling the generator wire out of its conduit and replacing lock, stock, and barrel, and I was looking forward to this as it's a simple straightforward task I can apply myself to directly (unlike the highest-tech project aspects which my husband is handling exclusively).

However it was so danged cold (39 degrees at high noon) that the conduit became unmanageable. It's a heavy gauge conduit and it stiffened up to the point where it would have been a fool's errand to try to manipulate it. As soon as I crawled under the chassis, I realized it was a no-go. So now we wait a few more days for warmer weather to resume.

[amirm]

I replaced all the solid conductor 10 gauge AC wiring with ancor stranded except the generator. I just got tired of spending time under there. Ours did not even have conduit around it! I remedied that by pushing some left over pieces I had.

Will have to replace it when the weather gets better. Solid core residential wire has no business on an RV.

[lewster]

Originally Posted by amirm

I replaced all the solid conductor 10 gauge AC wiring with ancor stranded except the generator. I just got tired of spending time under there. Ours did not even have conduit around it! I remedied that by pushing some left over pieces I had.

............................ Solid core residential wire has no business on an RV.[/B]

You sure got that right!!!!!!

[Boxster1971]

Originally Posted by amirm

I replaced all the solid conductor 10 gauge AC wiring with ancor stranded except the generator. I just got tired of spending time under there.

. .....Solid core residential wire has no business on an RV.

Nearly all RV manufactures use solid copper wire for 120VAC circuits. Is there any documented evidence that this wiring causes problems?


- - Mike
2013 Lounge EXT on 2012 Sprinter

[FlyFishinRVr]

Originally Posted by Boxster1971

Nearly all RV manufactures use solid copper wire for 120VAC circuits. Is there any documented evidence that this wiring causes problems?


- - Mike
2013 Lounge EXT on 2012 Sprinter

Thanks for asking this Mike as I was wondering the same thing! Solid core of the same csa as stranded has less resistance, so I would think this would be preferred when running off batteries (less loss).

[Troutboy]

All of the 120AC in my new AS is solid residential nomex type wiring. What is the issue with this, and why would AS use it if unsafe? It would be a MAJOR project to rewire all of this with stranded.




Thx
Troutboy, aka Rich

[FlyFishinRVr]

Originally Posted by Troutboy

All of the 120AC in my new AS is solid residential nomex type wiring. What is the issue with this, and why would AS use it if unsafe? It would be a MAJOR project to rewire all of this with stranded.




Thx
Troutboy, aka Rich

It's not unsafe at all. This is how all our homes are wired so no worries.

Solid core is definitely harder to work with in small spaces like those found in RVs, but that's a matter of convenience, not safety or performance.

[amirm]

Originally Posted by FlyFishinRVr

It's not unsafe at all. This is how all our homes are wired so no worries.

Oh, there is worry. Our homes do not constantly shake and bounce like an RV (and boat) do. That vibration is the enemy of solid conductor wires. This is why boating standards (ABYC) do not allow them. RVs have no standard so they use the cheaper residential wiring. Ditto for the residential circuit breakers without positive, screw terminals.

Solid core is definitely harder to work with in small spaces like those found in RVs, but that's a matter of convenience, not safety or performance.

That is another bonus of stranded wire. I am convinced it took more labor to install the solid conductor 10 gauge wire than to have used stranded wire. The outdoor rated solid conductor wire they use is extremely stiff. It took me and my wife at least an hour just to pull out the feed from the shore power because it simply could not be pulled with the bends in it.

[amirm]

Another no-no violated by Airstream is use of wire nuts in the circuit breaker panel. It is banned by ABYC and it has no place where vibrations could make it come loose. It takes 30 seconds to use a butt connector and do it properly.

[lewster]

The issue in not one of current carrying capacity, as ROMEX is the standard wiring in residential and commercial use.

The issue actually IS one of safety as solid copper will eventually work harden and crack or break from repeated movements and vibration.

Your house DOES NOT GO BOUNCING DOWN THE ROAD like an RV does.

You will NEVER find any solid copper conductors used in the marine industry as the ABYC (American Boat and Yacht Council) specifically excluded it's use in their electrical standards. An RV has far more in common with a boat than a house!!

The main reason that The RV industry still clings to their use of ROMEX for AC wiring are two fold:

IT'S CHEAP!!!!!!!

It's the only type of wire that can be used successfully in the RV-type 'speed wire' outlets that you find in the shallow walls of RVs.

Ever remove one of these type outlets and look inside????? They are a HORROR SHOW and a short waiting to happen. Over the last 16 years of doing RV service, I have replaced numerous speed wire outlets after catastrophic failures, along with trying to locate opens and wire breaks INSIDE insulation on ROMEX RV wiring. Never had an issue with stranded marine cable.

Your rig........your choice.

ROMEX has no place in a moving RV, just like it has no place in a boat!!!!


Lew Farber

[amirm]

Originally Posted by Boxster1971

Nearly all RV manufactures use solid copper wire for 120VAC circuits. Is there any documented evidence that this wiring causes problems?

It has been studied in boating applications and banned from use. The only thing different in a boat compared to RV is higher risk of corrosion. Even that risk exists in RV use. I am just not going to second guess that research and safety recommendation and take shortcuts.

I think these issues are taken much more seriously in boating because your life literally depends on these systems working. A stranded boat may sink. A stranded RV, possibly not.

How many mysterious failures do people report of their RV wiring? A lot. How much of it could have been avoided with proper standards of safety and reliability? Fair amount.

One of my main motivations by the way for pulling out the shore wire AC feed was that it ran through a cut section of the chassis and the only thing that was protecting the wiring was electrical tape! Electrical tape. No grummett. Vibrations will nicely cut into that wire over time like a knife and you would have a disconnect or short.

One day I happen to look at our home furnace as it was running and I see this flame shooting across an area that there should have been no flame at all. Quickly shut it off and open the panel and I see that a shield that was in front of the burners had one of its screws come out due to vibration. It then fell over sideways on top of the gas tube for the pilot light. With additional vibration it had sawed a slit into the gas pipe causing gas to escape and catch on fire! All happened because of what we are talking about here: not using proper screws with locking mechanism to not come loose to begin with, and how easily vibration can even cut through metal with a blunt piece of sheet metal.

Ultimately we all have to think about what going the extra mile does for us. In my case I have seen enough failures to spend the few dollars to re-do these things and sleep easy. The safety and comfort of my family is at stake and I would hate to not apply what I know to make this home on wheels as good as I can make it.

[73shark]

Originally Posted by lewster

The issue actually IS one of safety as solid copper will eventually work harden and crack or break from repeated movements and vibration.




Lew Farber

Same reason I think that soft copper tubing shouldn't be used for the propane line.

[Boxster1971]

Thanks to Lew for sharing his experiences. I think he hit the key issue -- solid Romex style wiring is cheap and none of us want to pay $200,000+ for our Interstates. The only RV manufacturer I know of that uses stranded wire for the 120VAC circuits is Advanced RV and at their price point one would expect stranded marine wire.
Too bad the Recreation Vehicle Industry Association (RVIA) doesn’t set wiring standards like the American Boat & Yacht Council (ABYC).

[InterBlog]

My husband was convinced of this need to rewire from his own research. RVs vibrate much more than boats do. He simplified the problem description for me as follows. The vibrations eventually lead to small cracks in solid wire. The electricity then has a smaller cross section through which to travel, which leads to heating, which could lead to fire.

I've witnessed the phenomenon myself in other contexts. In heavy industrial settings, we sometimes have trouble with wire damage imparted by ceiling-mounted air handler units. Those huge suckers impart vibrational energy indiscriminately to their surroundings 24/7, especially in Houston where the climate control never shuts off. I had one client who had a ceiling conduit in proximity to an AHU and eventually the wire/conduit combination became compromised. It spontaneously arc-flashed in a huge explosion that blew the entire manufacturing plant off-line for days. Between the equipment damage and the down time, I bet that operator was approaching seven figures in financial losses before they got the mess fixed and the plant back online.

If this process of wire compromise begins to happen, it's not really detectable until that fire or arc flash or if you're luckier, stuff just stops working.

My husband re-wired the roof a/c and microwave on Saturday and maybe a few other items. At one point he was cursing because of the way he found a junction put together. We'll probably be doing the generator this weekend.

[FlyFishinRVr]

Originally Posted by amirm

Oh, there is worry. Our homes do not constantly shake and bounce like an RV (and boat) do. That vibration is the enemy of solid conductor wires. This is why boating standards (ABYC) do not allow them. RVs have no standard so they use the cheaper residential wiring. Ditto for the residential circuit breakers without positive, screw terminals.

Interesting!

I've actually seen the opposite, where stranded wire was improperly stripped, cutting through some strands and scoring others such that over time, with vibration those strands eventually broke. The reduced current carrying capacity resulted in overheating, which of course lead to the eventual failure of the remaining strands and viola, circuit failure. Granted, this was on a twin-cylinder motorcycle which vibrates a heck of a lot more than an RV, but I would think the failure modes would be similar. I've also seen where stranded wire was incorrectly secured to screw terminals and "bad things" happened....

I guess there's no failsafe way to wire these things, but I'll drive mine anyway. After all, my house actually DOES shake quite a lot (I live in California after all ), to the point where I had early failure of my sub-panel (not uncommon here), but I keep living in it.

[lewster]

Now you know why I only follow ABYC electrical standards. They cover just about all requirements for wiring, from size of wire, types of wire insulation, wire terminations and their ampacity, etc.

If even a single strand of a multi-strand cable is comprised, it should be cut back to the insulation and stripped again.

Proper crimping and the use of crimps and cable terminations is a science to itself.


Lew Farber

[amirm]

To be clear, there is more to it than just using stranded wiring. The cable needs to be immobilized, terminations with proper strain relief used, etc. And of course high quality cabling utilized. Done that way I think the RV will outlast many of us.

That is the other thing I did by making sure the AC cabling had less opportunity to vibrate/move under the chassis.

[Troutboy]

Speaking of crimps, just got my new travel trailer (I know this is an AI thread). Anyway, as I was tightening battery connections, two of the crimps came off!! Pretty poor work on a new unit..... I can see the importance of termination, also, no heat shrink. This was on stranded wire going to the inverter.

I think it is impossible in this new trailer to replace the romex without ripping out the walls. Something I will have to wait a long time for. When I do a solar upgrade over the next few weeks, I will replace all easily accessible romex.

Unless I am missing something, you can't replace the majority of it without taking walls off???




Thx
Troutboy, aka Rich

[FlyFishinRVr]

Originally Posted by amirm

To be clear, there is more to it than just using stranded wiring. The cable needs to be immobilized, terminations with proper strain relief used, etc. And of course high quality cabling utilized.

Very good points, totally agree. In fact, I'd argue it's more important to properly route, tie down, protect, and connect the wires than whether the wire is stranded or solid.

@lewster - Crimp? Sure....but only if you also solder. Crimping alone, unless it is gas-tight (which most aren't), will be susceptible to oxidation and problems down the line. By totally coating the connection in solder, it's sealed and as amirm states, will likely outlast the owner. I also add heatshrink to finish the job.....