Wiring

[Seangie]

I've got romex for all my 110.  10 gauge stranded for DC.  I've had no problems.  For DC circuits I over compensate for wire gauge.

I've checked temps on wires during highest load and no heat issues.  No brownouts at termination points.  No cracks or wear.

Some notes if you run wire through conduit-

1. Typical rule of thumb is that the conduit needs to be half empty to allow for airflow and heat dissapation.

2. All wires in the conduit should be able to carry the load of the heaviest wire.  So if you have 12 gauge carrying 10amps at 110v don't put it in a conduit with 14 gauge or 16 gauge wire.  If the sheathing ever wears or wires break at termination and slide back into the conduit it could be a fire hazard.



Also -

Blue Sea Systems has a phone app called "circuit wizard" which is a great app for determining wire gauge based on loads and length and percentage of time the Max load is on the wire.

Here is a screenshot from the app -


My biggest electrical issues have been 20 amp 110v from a house plugged into my 20amp to 30amp to 50amp adapters. The adapters don't seem to hold up under a constant 15 amp load. 

Also I've seen where the Edison outlet on the house side is 15amp on a 20amp breaker and quickly browns out with a constant load.

Check your adapters!  If you have a pin on an adapter that is browned out or plastic melted around it or has black pock marks...get a new one!  That's where the fire will start.

-Sean (not Welsh)

[Gordie Allen]

11.   MC Cable also comes in solid wire and would be best used with DC for higher current/power loads.

If solid is better why is the best 4/0 DC cable fine strand?

[daddyoften]

I'm cornfused...
How is solid better for dc?

Sent from my XT1254 using Tapatalk

[bobwoo]

This goes back to the beginning with Nikola Telsa and Thomas Edison. DC current goes one way and sits until needed, When needed it flows fast creating more heat. Solid copper takes the heat better but you need larger wire than you will for AC. It all goes back to the Laws of Thermodynamics. That's what the pointy head engineers say 

[goldgiter]

              Bouncing down the road at 65mph.
                                  Merle.

Lol, I was being somewhat of a smart a$$ when I posted that. I honestly don't believe there would be enough movement in the wiring to cause a problem. I do think over loading the wiring or varmits chewing thru the insulation is something to be concerned about, as has been posted. I used bx for my conversion simply because it is metal clad and less likely to be penetrated by a screw or nail.

Wes

[luvrbus]

This goes back to the beginning with Nikola Telsa and Thomas Edison. DC current goes one way and sits until needed, When needed it flows fast creating more heat. Solid copper takes the heat better but you need larger wire than you will for AC. It all goes back to the Laws of Thermodynamics. That's what the pointy head engineers say 

That makes sense now I know why all the big locomotives here use solid wire lol and they vibrate big time

[Iceni John]

11.   MC Cable also comes in solid wire and would be best used with DC for higher current/power loads.

If solid is better why is the best 4/0 DC cable fine strand?

If 4/0 were coarse-stranded, like THHN, it would be very hard to bend, and if it were solid it would be like a grounding rod!   Most readily-available 4/0 is welding cable that needs to be very flexible.   It's also much better to crimp lugs on fine-stranded cable than coarser-stranded cable  -  it's almost impossible to get a good solid gas-tight crimp on coarse-stranded cable with typical consumer-grade crimping tools that can exert only a few tons of force.   I tried crimping some lugs onto THHN with both my big FTZ 94284 crimper and my small hydraulic crimper, and neither gave me as good results as with welding cable.   Maybe a big industrial crimper would work on coarse-stranded cable, maybe?

This was one reason I used solid metal-jacket 10/3 for my AC wiring  -  I could form the ends into precise loops that secured very well under the terminal strips' screws inside the junction boxes, much better than trying to crimp lugs onto coarse-stranded MC.   I secured this cable every 10 to 12 inches, and it is absolutely immobile.

John  

[bobwoo]

The question what was best, not what was practical 
BX cable is the same as MC but BX has no ground. It uses the metal jacket for the ground. It's also getting hard to find.
Welding cable is SO and is very good but higher priced.
As long as you size the circuit properly and follow good installation practices any wire, even romex is fine.
We all play Russian Rolette with AC power in this application. With no direct ground just one mistake can kill you or burn it down. Under sizing the wire will burn it down, improper termination will burn it down, be it AC or DC, stranded or solid.
If in doubt spend the extra money, use better grade devices, go 1 or2 wire sizes larger, use BC, MC, SO cable for greater protection. Use GFI devices. Fuse/breaker the circuit properly. 
Electricity isn't forgiving, doesn't understand, don't allow do overs,,,,,,, it will kill you,,, just be careful, plan, and know what a circuit is doing before running it.

[goldgiter]

The bx I use has 3 wires! Also bx is solid wire.

Wes

[bobwoo]

Like to hear thoughts on AC/DC bonding and grounding 1 point, 2 points, to bond or not to bond
Do you bond the main panel and have a ground for each AC / DC?
Just curious

[digesterman]

Properly wiring your bus is important if your building, proper maintenance important if store bought, BUT would like to see stats on fires, deaths etc directly related to the wiring in motor homes and buses, not to many I think.
Do it right, doesn't take a rocket scientist to figure it out.
Don't think we need the doom and gloom and talks of death.
Driving your bus across country is far more dangerous imho

[lvmci]

Hi All, I  work with television trucks, you may have seen shots of the director looking at a massive wall full of 50 or so television screens connected to cameras out in the field or the arena. These 53ft tractor trailors packed full of every imaginable electronic device, wire, monitor, and electrobic board and computer, these trucks drive mostly on the Interstate,  then city streets to get to the showrooms and arenas. These multimillion dollar trucks and trailers, designed by some of the best electronic engineers in the world, have three electronic engineers, that travel with the trucks to each venue,  and as we're  setting up cameras they are figuring out what broke, came loose, cold solder point broke loose, wire got sliced or crimped and melted, and every imaginable  problem causing electronic failure. Mostly because of vibration on the hiway, tom, lvmci...

[luvrbus]

You need to those guys to go to air ride trailers Tom

[lvmci]

Hi Clifford, they are air ride and very smooth, it's the twists, turns, pot holes and wear and tear, just like our buses, that cause the wires and connections to break down, tom...

[digesterman]

I must be riding on the smoothest roads in America (NOT, California hwys) we just DO NOT experience the vibrations that you guys are. We have a coffee bar in one of the bay's that when we travel we don't go to any trouble to put cups sugar etc etc away, and we don't have any breakage when we get home. Maybe Prevost rides are better? Maybe I'm just one heck of a driver 👍(probably it).
Back when we had S&S RV's they rattled and vibrated to beat all, and I can't recall one wiring failure. Just saying