AC Electrical Wire Choice Romex vs Stranded

[thrifty bill]

The one remaining section of original wiring on my Trillium is the 120V AC outlet circuit. It uses those odd RV outlets that kind of spear the wiring. The wire is stranded type, which is typically recommended for RV service.

I really would prefer to use conventional outlets with Romex wired to screw terminals. I never really have mastered the spearing process, my work is less than stellar on it (I did replace one outlet).

So to those that have repaired/rewired your trailers, what did you do? Maybe I just need to learn how to use the RV plugs? Or maybe the source of the right tool for this job (I love tools!!)?

[John in Michigan]

In my Boler 17, I have added two conventional outlets using romex. The trailer already had four original outlets, all conventional, that were wired using stranded wire. I also replaced the converter and upgraded to 30 amp service. The 30 amp wiring between the trailer inlet and the converter is two feet of stranded 10 gauge inside conduit.

[Jon Vermilye]

My preferred receptacle for RVs (and anything else, for that matter) is construction grade back wired. They can be side wired under the screws, or back wired, using the side screws to clamp the back wires, rather than the stab type. They can be used with either solid or stranded wire. Example

The RV receptacles are designed to be fast, and don't require a box, but they are difficult to replace, requiring fairly expensive tools. Example

[CarlD]

Just use romex and receptacles with screw terminals and make sure the wire is securely attached throughout the run so it doesn't move. As Jon said the back fed screw terminals are easiest to work with.

[Bob Durrstein]

Given the environment of the system, I chose heavy duty construction out door 23==12/3 extension cord wire to get the durability and flexibility. Easier to run and a tad bit safer in my view.

[CarlD]

If you are using stranded wire make sure your receptacles are compatible. The original wiring the OP mentioned is stranded and designed to work with IDC terminals but not with solid conductors such as romex.

[steve dunham]

The NEC does not allow extension cord to be used as a permanent, concealed wiring method . I’ve seen twenty year old extension cord where the insulation is so brittle if you bump it the insulation falls off . That’s why the code requires cord to be visible along its entire length .
NM cable ( Romex) has been age tested and is approved for concealed work .

[thrifty bill]

So Steve, I know you are quite knowledgeable on all things electric. Would you use Romex on a trailer? I am leaning that route as I would rather have a good connection with Romex (screw terminals on an outlet) than a mediocre connection with the stranded stuff.

Agree cord does not age well.

Yes if I go Romex I would replace the crappy outlets on my Trillium.

[steve dunham]

Originally Posted by thrifty bill

So Steve, I know you are quite knowledgeable on all things electric. Would you use Romex on a trailer? I am leaning that route as I would rather have a good connection with Romex (screw terminals on an outlet) than a mediocre connection with the stranded stuff.

Agree cord does not age well.

Yes if I go Romex I would replace the crappy outlets on my Trillium.

I have added 120VAC receptacles in all three of my FG trailers and all were wired using NM ( Romex)
I use commercial grade receptacles as Jon V recommends .
When I terminate stranded wire on a receptacle , I either use the backwired screw clamp style connections or I crimp on fork terminals .
I do NOT use the stab/ pushin terminals on electrical devices , they were simply designed to cut costs IMHO

[Bob Durrstein]

Thank you.

[Arthur II]

Just to be on the safe side ...

There's a reason that you don't see solid wire such as Romex used in anything that is subjected to prolonged vibration. That being the case I have always used stranded for all trailer rewiring over the years.


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[steve dunham]

Originally Posted by Arthur II

Just to be on the safe side ...

There's a reason that you don't see solid wire such as Romex used in anything that is subjected to prolonged vibration. That being the case I have always used stranded for all trailer rewiring over the years.


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The factory wiring in my Scamp was Romex with solid conductors
The factory wiring in my Casita was Romex with solid conductors
The factory wiring in my Escape is Romex with solid conductors
The factory wiring in Forest River trailers is Romex with solid conductors
Your free to use what you wish in your trailer , I use NM cable because it meets the code , is inexpensive and in my 40+ years as a licensed electrician I’ve not encountered a product failure .
At some point , cost , ease of installation , safety, and realistic expectations have to enter the picture
IE; Gold conducts better than copper but if we used gold for wiring , no one could afford a home.

[Arthur II]

Originally Posted by steve dunham

Your free to use what you wish in your trailer , I use NM cable because it meets the code , is inexpensive and in my 40+ years as a licensed electrician I’ve not encountered a product failure .

If you notice, I referred to "prolonged vibration". I never said it wasn't used in trailers. It's just my personal choice based on what I've seen and experienced over the years.

Personally, I have over 40 years as a certified professional in the electrical/electronics field. Including residential, industrial and Government. So, pardon me if I tend to be a bit biased in my personal decisions.

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[gordon2]

Originally Posted by Arthur II

...
There's a reason that you don't see solid wire such as Romex used in anything that is subjected to prolonged vibration. ..
.

Originally Posted by Arthur II

If you notice, I referred to "prolonged vibration". I never said it wasn't used in trailers. ...
.

So, since I have solid (NM) wire in my trailer, should I limit the number of hours I tow per day? Or the number of days out of the year that I tow? Just when does it become prolonged, with the risk of failure?

[thrifty bill]

Originally Posted by steve dunham

I have added 120VAC receptacles in all three of my FG trailers and all were wired using NM ( Romex)
I use commercial grade receptacles as Jon V recommends .
When I terminate stranded wire on a receptacle , I either use the backwired screw clamp style connections or I crimp on fork terminals .
I do NOT use the stab/ pushin terminals on electrical devices , they were simply designed to cut costs IMHO

Thanks, I will seek out the better receptacles for sure.

I hate the stab terminals, wondered if it was a cost/speed decision.

+10 good enough for Escape, Scamp, and more. The Trillium is not going to see big miles, but the Escape has.

On the extension cord front, the wiring on my old Dometic refrigerator sure looked like an extension cord. Not positive, but the wire appeared to be aluminum too. The casing/jacket totally failed.

[gordon2]

Originally Posted by thrifty bill

...
I hate the stab terminals, wondered if it was a cost/speed decision.
...

Sure is.. and I am not an electrician, just a home owner, and I have seen a few failures with the back stab connections on the outlets.. two of which caused a lot of heat and posed a fire risk. I always take the time to use the screw terminals.. no one is paying me for my time.

[CarlD]

Gordon,

The best thing you can do is make sure none of your wires have resonant frequencies similar to your trailer. This will greatly increase the longevity of the wiring for a few decades! And don't subject it to impulses because they are broad band and will contain frequency components in the wiring resonant range! The mass of your trailer compared to the mass of the wires and your trailer suspension are your friends!

[Raspy]

It seems reasonable to question romex use in trailers. But has anyone seen a failure of romex that was caused by the movement of the trailer? I get that the receptacles used in trailers are usually the worst type, but that is not a romex failure.

RVIA, the agency that certifies the systems and designs in trailers, apparently has no problem with romex. Mine is RVIA certified and it uses romex.

I prefer to use stranded #12 PVC jacketed contractor extension cord wiring for things like brake wiring, that might be exposed outside or more subject to flexing. I bought a 100' high quality cord and have been using sections of it as needed, for all kinds of things. Marine romex is even better because it is tinned, but standard household romex, if properly mounted and connected, seems fine.

[steve dunham]

Originally Posted by CarlD

Gordon,

The best thing you can do is make sure none of your wires have resonant frequencies similar to your trailer. This will greatly increase the longevity of the wiring for a few decades! And don't subject it to impulses because they are broad band and will contain frequency components in the wiring resonant range! The mass of your trailer compared to the mass of the wires and your trailer suspension are your friends!

You also need to take into account harmonic distortion especially the 3rd , 5th , 9th and 11th harmonics . They make cables with super neutrals to combat this issue so if you carry a lot of electronic equipment with you when camping you may wish to consider this
Another way to limit harmonic distortion is to use a K rated transformer or a battery back up UPS system .
The only electronics we carry when camping is my wife’s flip phone which in over 10 years of camping is still unscathed.

PS ; We have had an issue with a receptacle in our Escape . Escape uses the RV style plug in receptacles without a box . The branch circuit wires were not properly terminated on the receptacle causing the receptacle to heat . This was not the fault of the NM wiring but was the fault of poor workmanship

[Markz]

Use Romex but make sure the cable is secured along its run so it can't come loose. I use plenty of zip tie squares or other anchor points along the way.

Organized wires are visually attractive and generally safer.