From the original post:
Originally Posted by bcschro
. . . Do I have to take out the 12v wire I ran and replace it with 12 RV two strand wire? And where can I buy 12v RV 2 strand wire at. . .
I was over-thinking the original question, as I had never heard of "RV 2 strand wire." I was picturing two solid conductors twisted together inside the insulation, which did not make sense.
The wire would be as inflexible as one solid conductor, and would be very expensive to manufacture.
Others seemed to interpret this reference as "2 conductor" wire, with separate insulated hot and ground wires. The conductors would either be together in another layer of insulation, or it could be "zip" cord, with the insulation of the two wires joined side-by side.
Hours after making my first post, it dawned on me that someone probably told bcschro that "Number 2" stranded wire was needed for a particular high-current application. Duh!
So it seems we have had quite a discussion since then. Remember, we all have different purposes for our buses. There are three levels of concern, and all of us operate at one or more of these levels, sometimes alternating between them:
1. Will it work?
2. Is it safe?
3. Is it compliant with the National Electrical Code?
1. There are a lot of things that "work," whether they are safe or not. The example cited of the washing machine running on lamp cord working for a while (until it didn't) is one of these. People who temporarily cut corners because they know what they are doing, and know and accept the risks, may be fine for them, but they should not teach their practices to other people, nor leave their jury rigs anyplace where other people might come into contact with them.
I don't care about stories of what you "got away with." (Except for entertainment value
For a personal example, once I was deep in the woods with two other people, driving a truck and a van. When we wanted to leave, the van would not start because we had been using the accessories for an hour or more. We didn't have jumper cables, but we did have a 20-foot length of #6 wire. We cut it in half, bared the ends, and left the truck running while two of us held the bare ends with our thumbs onto the battery posts of the two vehicles. The third person started the van. YOW!
I and the other person
burned our thumbs on the hot wire. This "hillbilly" emergency measure "worked," but I would never teach someone to do it, and would always instead teach: "Always carry jumper cables."
2. There are a lot of things that are basically "safe," but not to code. A heavy-duty extension cord with no splices in it, run direct between the source and the device while being drilled through wooden partitions would "work" and be "safe," as long as there was nothing that could mechanically cut into it. But I think it would certainly not be code, as I think cord must not be used in permanent installations (with possible exceptions of links to stationary machinery). Running the cord through a sharp hole in a metal partition without a protective bushing would be different.
The question of "safe" should not only include how you intend to use it, but also protection against uninformed strangers. If the toddler from the next campsite comes over and touches your bus while standing barefoot in wet grass, that cannot be a fatal mistake.
3. Wiring to code is a different animal. And to add to the confusion, the code is constantly changing. When I was a kid, there was no such thing as a ground-fault breaker. We had fuses that screwed into 'medium Edison' holders in a fuse box. This was the kind where people were known to replace a blown fuse with a penny to get unlimited current and no more blown fuses.
Remodeling in the early 1960's, the house got circuit breakers, but still no ground fault interrupters. Today, you cannot wire a bathroom, kitchen, or outdoor outlet without one. Should all the old houses be torn down just because the safety pointer has moved? Are owners of older houses criminally liable because new technology has been developed, but they did not implement it?
Another example: In my current job, I inherited two 5.5 kW solar systems built in the early 1990s. Each system has two arrays of 9 strings each. Each was installed with two circuit breakers, one for each array. Today, the solar section added to the code says that each system would need 18 over-current protection devices (fuses or circuit breakers), one for each individual string. Are the systems that have "worked" and were formerly "safe" for 20 years now "unsafe" because a section of code has been added?
I won't advise anyone to do any work that is not to code, but neither will I insist that anyone comply with the RV sections that were written by sticks-n-staples makers for sticks-n-staples makers to protect their business. Commercially made RVs never catch fire, do they? Still, many "best practices" can be gleaned from knowing the sections, even if some of them seem to be overkill (or over not-kill?)
When you ask about electrical issues, a layman and an electrician will give you different answers.
Ask about wire size, and a layman might answer something like:
#16 - 10 amps
#14 - 15 amps
#12 - 20 amps
#10 - 30 amps
# 8 - 40 amps
# 6 - 50 amps
# 4 - 75 amps
# 2 - 80 amps
There are probably tens of thousands of homes wired by homeowners using rules of thumb like these on short wire runs, after reading "Popular Mechanics" and using listed devices obtained from the hardware stores. The work could have been done without a licensed electrician, either secretly or where allowed by building codes. I'll bet there are thousands of vehicles similarly wired, too.
If you ask an electrician what wire to use, the answer MUST
be "it depends." His license and all his future paychecks depend on it.
All wire has some resistance, and resistance generates heat when current flows through it. Therefore, all
wires and devices generate some amount of heat when in use. A licensed electrician must consider the accumulation of heat in de-rating the capacity of wire and devices.
The electrician must consider: "How long is the wire run?" "What does the wire run through?" "Is it exposed or enclosed?" "How many other wires are bundled with it?" "What is the environment?" There are various tables, charts, or calculations used to arrive at the values that will pass the code.
If Lorna wires her own bus like the picture she posted, and knows that the bundle powers a night light, a table lamp, a microwave and a laptop, though not to code it would be completely "safe" for her purposes, as long as protection against metal framing cutting into the wire insulation was employed. An electrician could not do the same thing for other people, because the wiring would have to be able to disburse the heat while the owner perhaps used two space heaters, a waffle iron, toaster, microwave, and hair dryer, all at the same time. The wiring would have to be over-sized, spaced apart, or de-rated to allow for that possibility.
Something no one else has covered is rodents. Have you ever taken apart a piece of non-working equipment, only to find the remains of a mouse with its teeth still sunk into the AC wires, memorializing its last act on earth? Have you ever seen a building where a porcupine has eaten a hole through a wood floor, had a rubber propane hose for lunch, and ate all the telephone wire insulation it could reach for dessert? I personally like to use metal conduit or armored cable when I can, knowing how much rodents love the taste of plastic.
I am a "radio man," not an electrician. I do not "play [an electrician] on TV." And I did not ever sleep at a Holiday Inn Express.
I do not have copies of the electrical code, except for the excerpts quoted on the internet. But I do have to know enough about the code to be able to to sign off on electrical sub-contractors' proposals and completed work. For example, I had to devise a plan to properly add a 70 kW emergency generator to part of a commercial building having 216 kW electrical service. Another project I signed for was a half-megawatt battery backup system. And I have worked on dozens of skoolies, a few transits, plus a couple of coaches.