Conductors for AC in vehicles

[DisasterGuy]

My primary work is portable power, electronics, and general field tech. As a crossover of several of those things, I deal with several situations where AC wiring is required in various vehicles (trailers, mobile command buses, emergency vehicles, etc). There appears to be a great deal of variance and lack of standard for AC wiring in automotive type applications. The RV industry likes romex (even though solid wire is less than desirable in mobile applications), the emergency vehicle industry likes SOOW, and in inspected vessel applications a stranded "marine romex" is used. I have also seen some trailer builders use stranded THHN in EMT.

Does anyone have any thoughts on supporting the use of one conductor / cable type over the other along with any relevant code/standard references?

 

[LarryFine]

How about MC? Flexible, yet armored.

 

[tom baker]

I would suggest multiconductor tray cable. Its 600 V rated, direct burial, has jacket, what I used had XHHW insulation on stranded wires. NEC now allows it to be used in place of NM cable. Get some catalog cuts from Belden.

 

[Todd0x1]

How about MC? Flexible, yet armored.

Stranded conductor MC would be good so long as extra care is made with the anti shorts. Vibration in something like a trailer has funny ways of making materials in contact saw through eachother.

I would probably lean toward tray cable, ordering the <colors>/white/green version. Off the shelf 3C tray cable is going to get you black/red/blue. Terminate it in compression type cable glands, for the love of god don't use screw type romex clamps.

LAPP and others also make tray cable in a more flexible version for applications where the cable needs to flex.

 

[Hv&Lv]

I would suggest multiconductor tray cable. Its 600 V rated, direct burial, has jacket, what I used had XHHW insulation on stranded wires. NEC now allows it to be used in place of NM cable. Get some catalog cuts from Belden.

Wonderful choice!
It’s what we use for control, metering, and power wiring..
Cuts down on inventory. Just use it for everything

It’s what I used on my trailer wiring also.

 

[junkhound]

Last year I wired up my Grand-daughters school bus, 190 solar array, inverters, 120Vac, etc.

Wired like commercial aircraft - used everything from THWN to BMS13-60 wire.
No conduit, simply routed with cable clamps and ties so there is no contact with structure and no possibility of contact due to vibration.
example: heavy zip ties to cross frame members under the bus with old pieces of rubber hose between structure and wire bundles, etc.

two round trip coast to coast drives so far, no wiring problems.

 

[DisasterGuy]

Thanks. I hadn't really considered tray cable. I do use it a fair amount (in 18 and 16AWG flavors) for control wiring applications. Any specific reason why there may be an advantage to TC over SOOW?

 

[tom baker]

SOOW would need conectors for fine stranded wire, TC would be available in more sizes and conductors. Not sure about cost. I suspect tray cable may be more fire resistant.
Also, the American Yacht Council has specs on marine wiring.

 

[Todd0x1]

SOOW would need conectors for fine stranded wire, TC would be available in more sizes and conductors. Not sure about cost. I suspect tray cable may be more fire resistant.
Also, the American Yacht Council has specs on marine wiring.

TC is generally cheaper than SOOW. Where subjected to repeated flexing or maybe heavy vibration you might want the finely stranded TC which costs a bit more than regular TC. We did a big custom trailer project with a mix of fine stranded TC and UL1015. Used ferrules to land on breakers and contactor terminals, used wiring devices with pressure plate terminals, and used Wago lever nuts for splices. Worked out well.

 

[tom baker]

TC is generally cheaper than SOOW. Where subjected to repeated flexing or maybe heavy vibration you might want the finely stranded TC which costs a bit more than regular TC. We did a big custom trailer project with a mix of fine stranded TC and UL1015. Used ferrules to land on breakers and contactor terminals, used wiring devices with pressure plate terminals, and used Wago lever nuts for splices. Worked out well.

This seems like a good way to go, find stranded, ferrules, etc.