Wiring

[PRZNBUS]

I was told by a knowledgeable electrical friend of mine you shouldn't use house style wires in a conversion. He said something about they need to be rated for movement? He said either automotive, boat or even extension cords with the ends cut off are better choices but way more expensive than house rated wire. I trust this guy and can sort of see what he's stating but how many people are using regular house stuff?

Bruce

[MB LeMirage]

Most likely is the difference between house wire being solid core while auto/marine is stranded. More forgivability of movement and vibration resistance with stranded. Solid can crack over time.
Ryan.

[TomC]

I used 12 gauge stranded THHN rated bought at Home Depot $50 for 500ft, pulled through light weight plastic conduit. Hence you have to use three wires for grounding. 12 gauge is rated at 20 amps at 120vac. And since no run in a bus is more than 40 ft, you'll be good-especially if your using 15 amp breakers. Good Luck, TomC

[luvrbus]

This is a old debate Romex has always been used in the RV industry if anchored it will last seems like for ever.
I didn't use Romex I used the thinn marine wire and 10 years later I found out it wasn't recommend for RV use so who knows I wouldn't be afraid of using Romex .

I have a 30 year old Coachmen with it and a 1998 Trek wired with Romex fwiw never a problem with either and you don't need conduit for Romex it is double shielded.There is a section in the RVIA book on wiring fwiw     

[TomC]

I used 20 amp breakers on A/C, and 15 amp breakers on everything else. I wired my bus with 10 gauge-a bit over kill and harder to pull through conduit. I would use the conduit to measure my run then pull the wire through before installing. Good Luck, TomC

[Oonrahnjay]

     Extensions cords are sometimes used (and apparently with some success) but the pro electricians consider them not up to the task for RV/bus conversion wiring.  Since they're made to be light-duty and flexible versus vibration-resistant, I won't argue with that. 

[Cary and Don]

Seems like I read some place that the problem with extension cords is they get hot easy. With three wires wrapped together, it is harder for heat to dissipate.

The extra benefit of the stranded wire is, it is so much easier to pull through tight spaces. It is easier to mount on a post and clamp down in a breaker. We have both and the stranded is so much easier.

Don and Cary

[Oonrahnjay]

  Seems like I read some place that the problem with extension cords is they get hot easy. With three wires wrapped together, it is harder for heat to dissipate.  ...

    Yes, the light (for flexibility) construction is a factor in thin strands, easily broken by vibration or pulling. All the power goes through fewer and fewer strands at each wear/weak point until they melt down.

[Lin]

Although there may be superior options, the one factory RV I had and the two buses were all done with Romex.  This covers at least 30 years of experience and I have never had a problem with it.  Also, I know some people are very critical of using stranded extension cord but I question whether much of the opposition to it is more theoretic than real.  I am sure that some on this board have used at least some of it and wonder if they have ever had a problem.  If I wanted to use the stuff and also wanted to be cautious, I would just go with a thicker gauge.

[goldgiter]

I was told by a knowledgeable electrical friend of mine you shouldn't use house style wires in a conversion. He said something about they need to be rated for movement? He said either automotive, boat or even extension cords with the ends cut off are better choices but way more expensive than house rated wire. I trust this guy and can sort of see what he's stating but how many people are using regular house stuff?

Bruce

What would cause movement in the wiring?

Wes

[daddyoften]

All the vibrations of the vehicle constantly moving. It adds up over time. I don't have the numbers but there have been quite enough rv fires started because of wiring failures to ward me from using solid wire romex.  ALL vehicle manufactures use stranded wire in autos and trucks and factory bus wiring. It's possible some rv manufactures have used solid in their builds and I'm sure the majority of them have had no problems. But the ones who have are enough for me to not want that risk
FWIW
Eric

Sent from my XT1254 using Tapatalk

[luvrbus]

I don't think you see many RV fires caused by Romex wiring on the AC side most fires start on the DC side at some component like on any RV including the Prevost conversions with stranded wire,any type wire will start a fire when overloaded for long periods  JMO   

[scanzel]

I used all aluminum metalic sheathed 12 guage copper for everyting, keeps the mice from chewing into the covering.

[bobwoo]

Just a few tidbits re electrical:
1.   Best wire =A/C stranded, more current, D/C solid for heat. Never use anything smaller than 12 gauge wire. You have to think about the heat load.
2.   Don’t stretch the wire tight but secure it close to the termination points and so it doesn’t flop and move like a fish out of water.
3.   Don’t make sharp turns, loop the wire.
4.   Don’t make snug holes through dividers, keep it loose.
5.   Distance and CURRENT, know what the device draws. Just because its 12 volts don’t mean you can use 12 gauge wires. If it’s drawing 30 amps and a 40 foot run with 10 bends, go to 10 gauge wires.
6.   Termination points: use care making sure you strip enough but not too much insulation from the wire and never, I mean never use Home Depot 15 cent outlets and switches. Using the push in connector devices are ok in houses but we have vibration, use the screws with proper striped wire and tighten.
7.   MC wire is the flexible conduit that will keep you from making some of the mistakes from above and it doesn’t cost that much more. Make sure you use the bushings that come with the roll and again watch the termination points for wear. The wire is going to move. For the “non pros” get a mc cutter that will make cutting the cable easy and proper. 12 gauge stranded MC cable will flex enough to make the turns needed and not allow for too sharp of turns.
                                                                     DC wiring
8.   On DC; current and length of the wire run is most important because of the heat gain.
9.   Know the total current load of the circuit and go higher wire size.
10.   Termination points are most critical on DC because of corrosion. Use a good connecting and an anticorrosion ointment. When designing keep as much of the higher current DC termination points a little more accessible for inspections. Depending on use and load; yearly or couple year inspections.
11.   MC Cable also comes in solid wire and would be best used with DC for higher current/power loads.
To summarize just don’t go haphazard into the wiring of the coach. Know what you are going to use the entire circuit for.
Well that’s my rambling on with my 40 plus years as an Electrical/Mechanical Engineer, but what do I know.    Bob

[ol713]

What would cause movement in the wiring?

Wes

              Bouncing down the road at 65mph.
                                  Merle.