generic benroy plans 12 or 14 gauge wire?

[bronco]

im building my tear with the generic benroy plan and they list the wire supplies for hooking it up with 12 gauge for the d.c. and a.c. side of it.
but looking at alot of the archive pages in the electrical secrets section i keep reading that most people are using 14 gauge. is there a huge plus or negative to either gauge? electrical work is my major weakness so id like get your opinions before i screw something up. thanks for any info.
also in the plans: the shore supply inlet picture shows an extension cord plugged into it. what do you suggest i use. the standard r.v. plug connection or a standard type 3 prong wall type inlet. in the picture it didnt look like the extension cord had an adapter in between it and where its hooked up. thats why im asking.

[rasp]

for just lights 14 would be fine, but for plugs 12 would be your best choice. i would use the stranded type wire (THHN) not the solid wire they use in houses, as stranded take vibration very well.
most place i have camped at have at least the standard three prong outlet (15 amp), just like your house.

[madjack]

Bronco, we used 14ga(good for 15Amps) standed for everything except the power in lead...we used the stranded not because of the vibration thing but because it is easier to work with...we used 12ga for the power in lead and 10ga for the battery to fuse block lead...along with a 12v master switch and an inline fuse...used a standard 12ga extension cord and picked up a 30amp RV pole connector adapter...many campgrounds will have these available for sale(the're relatively cheap) if they don't have 20amp service available at the pole....
madjack

[GeorgeTelford]

Hi

Put as simply as possible for 12v dc circuits use the thicker wire, voltage drop is a big issue in low voltage appliances, its not so important at mains voltage ac.

If you want to do it right post the Ampage the appliance needs and the distance to the battery X2 and I will check out the chart to reccomend the optimum wire, this could end up calling for several different reels of wire, generally I would pick the thickest and use that throughout.

IMO Wire should never ever be rated at an ampage for 12v dc, this tends to confuse ameteurs into believing its good for that ampage regardless of distance which is simply not true, because 14 Guage may be good for 15 amps over a very short run say 3 ft there and back (remember positive and negative runs both count for the distance) but is entirely inadequate 6 ft away (thats 12ft of cable for pos and neg)

The stranded wire required due to vibration is an old wives tale, I have moved 60 year old industrial machinery and the internal wiring is "cloth" covered solid core and its still in good condition, this as been subjected to more vibration than a tear will see in 20 lifetimes.

Stranded wire or Flex is just that flexible if the wires is going to be moved relative to itself then stranded is needed, ie solid would be no good between the tear and the tow car, in this case it would "work" and break down, where the run's are fixed ie behind walls for Sockets, lights etc solid would be no probem. In most cases people will still use stranded as its easier to work with.

[rasp]

http://www.emarineinc.com/products/mounts/boatwire.html

here is a good source for electrical wire choice. yea, it has to do with boats, but your are building a land yatch, though smaller than most.

[asianflava]

For 12V outlets I used the heavier wire because I wasn't shure what load would be. For things that used very little current like my LED cabin lights and porch lights, I went as small as 14ga. It was easier to run the smaller wire.

[bronco]

thanks for all of the info. it helped alot, at least now i understand the reason for the gauge thicknesses and also the wives tale about the strande vs. solid wire issue. thanks again for your time.