12 volt

[RavensOracle]

Just run another wire back to the bus bar. It should be easy since you have already ran the one wire that way. I like to use color coded wires - red is hot, black is ground so it may mean that you have to get another roll of wire. I have also color coded separate hot circuits to keep from getting confused trying to trace a run. This was from my days in the Airforce when I had to build wiring harnesses for some of our equipment. It really sucked when you had a 100pin connector that every wire looked the same and each pin did something different.

[Redbear]

Originally Posted by RavensOracle

. . . . I like to use color coded wires - red is hot, black is ground . . . .

Except when you get into trailer and 'Stick-n-Staples' RV wiring, where black is hot and white is ground like AC wiring - be careful when mixing and matching equipment.

If you only have one battery string, using the vehicle chassis as your ground should not make any difference. If you have multiple strings, say four 6-volt house batteries in 2+2 configuration, it may make sense to use a bus bar to keep the battery wiring resistances nearly equal in order to balance the charge and discharge rates between the pairs. Plus, if you use battery capacity metering like a Tri-Metric, you will need to have a special large capacity/minute ohms resistor between the battery minus and ground in order to develop the signal to the meter. Having a battery ground bar insulated from the chassis is one way to have a place to connect the metering resistor.

The difference between solid and stranded wire has been debated here before. There is no specific conclusion, only what each person feels is most comfortable with for their bus. There is, as always, a cost versus quality decision to be made.

A number of RV manufacturers use solid house-type wiring in their AC wiring, and have the RVIA/NFPA specs written to accept it. In general, solid wire is to be used in places where the wire is bent once for installation, and does not move again after that. Solid wire that is bent back and forth will eventually break, just like snapping a piece of coat hanger. Some skoolies worry about road vibrations, and will not use it.

Wire that is meant to be bent, like extension cords, is instead made up of many strands of smaller conductors bundled together. Some stranded wire has a few thick strands, other wire has many, many fine strands. The smaller the strands that make up the bundle, the more the wire can be bent back and forth without harm. Wires for permanent fixtures probably don't matter, wires for accessories that move around like laptops or table lamps should definitely have stranded wire. The same is true for battery or generator wiring if there is a slide-out tray that requires the wires to move.

A word about stranded wire - if you see bare copper-colored strands inside the insulation, the wire will not be moisture resistant. I have seen my share of wires where any compromise of the plastic jacket that lets in moisture, even smaller than a pin-hole, lets the moisture turn the soft copper wire into hard, green powder. This powder will show voltage OK on a sensitive meter, but will not allow enough current through to run anything at the other end. I am not talking about "cord," where several wires are run together inside another protective jacket, but single-conductor colored 'hook-up' wire purchased from the auto parts or Radio Shack store. If the wire is "tinned," showing silver-colored conductors where the copper was bathed in solder before being put into the insulation, the wire will be more moisture resistant and last longer. It will also be easier to make solder connections to, as the solder has already been flowed into the molecules of metal in the wiring. (Solder is not "glue," but is a metal-to-metal bond.)

Good connections are much more important at low voltages than at household AC levels. A 21-watt turn signal bulb used for lighting draws 1.75 amps at 12 volts. A 25-watt incandescent AC bulb only draws 0.2 amps at 125 volts. A two-ohm resistance from a bad wiring connection would create 2.7 watts of heat and dim the DC bulb by about 25%, but at AC the heat would only be 0.4 watts and there would be no noticeable affect on the brightness. The same 2 ohms on a 12-volt, 600-amp starter cable would create 72 watts of heat, and limit the starter to 6 amps. If the connection were only half an ohm, it would supply 24 amps to the starter, generate 288 watts of heat, and give the impression of a dead battery until the fire started.

Some Skoolies will spend extra money and only use marine-grade wiring on their buses, with smaller strands and presumably higher quality insulation. They feel the extra money buys peace of mind. This may be a little bit of overkill for most of our purposes. But paying attention to what kind of wire we use, plus using zip ties, tubing, or other supports to prevent unwanted motion of the wires will go a long way toward making safe and reliable wiring.

[chev49]

Above post is correct of course. esp about color code for wiring.. In my case, I got a integrated electric control panel, and all wiring out of a monico coach which has the generator feed, land feed, switchover and fused panel for all 110v and 12v leads, including all tanks, etc. This makes wiring a bus very simple.

[lornaschinske]

A cheap way of getting good stranded wire is to use heavy (12 & 10 ga) extension cords (what we are doing since we have many extension cords left over from our prior occupation). Even Fred Hobe (pro coach converter) uses extension cords... and they are neatly packaged together if you need them like that. All those green Christmas cords should be on sale now.

As for the ground bar. The one in the Blue bird is real nice. It's also filled up and grounded to the frame. Since we only need the battery bank and the AC/DC panel box grounded, we will ground those to the frame. Everything electrical will go thru the panel box.

[wtd]

I have ran one wire for my 12 volt. I had planed to ground to the body because it is grounded to the frame.

This will work fine, just like an 'automotive' system - at least when they used to make cars outta metal

Do I have to take out the 12v wire I ran and replace it with 12 RV two strand wire?

Nope. No need for a separate ground wire to each fixture.

And where can I buy 12v RV 2 strand wire at.

Don't need the second conductor -just doubles the cost.

Tom

[bus-bro]

Geesh Lorna. On some bus sites, recommending the use of extension cords for fixed wiring has caused many a battle.

[lornaschinske]

Originally Posted by bus-bro

Geesh Lorna. On some bus sites, recommending the use of extension cords for fixed wiring has caused many a battle.

http://users.cwnet.com/thall/fredhobe.htm
"Tips from a Pro"

" I don’t post much on the BB's as most take it off, thinking that I am advertising. I have put on free seminars at my shop for the people that are converting a coach and want to do a good job and do it right. Twelve years ago there was very few coaches being built . And fewer builders to get advice from. Now with all the BB's and BCM everyone is trying to build a coach, and a lot won’t ask for help. It hurts me to see so many poorly built coaches out there.

These tips are only one way to do these things. Use them to get yourself thinking and as a starting place. I know that there are hundreds of ways to do all these things some better than others. I look and try to do each coach a little better than the last. To build one is a learning curve. If I can get those who read these tips to start thinking, then you can make improvements and you will have a lot better coach."

Fred Hobe

Way to save money on wiring
I buy 100 foot extension cord when they're on sale number, 12/3 conductor wire size. I can get them for as little as $15.00 and they come in different colors. I get several different colors and use yellow for air conditioners, orange for lights, black for wall plugs (120 volt) and green for 12 volt. They are UL approved and very flexible. You need to tin the ends when you hook them up to your main and on other connections use High lugs. Use an indent sqeezer to make good connections. You can buy 100 ft. cords with plugs on them cheaper than you can buy the wire by the foot. I use about 500 ft. of wire on a coach.


This shows how wires are run in the roof. Run them were they will come down the wall to the fuse panel.

For starters, I take Fred Hobe (North Florida Conversions) advice over many others.

[bus-bro]

There are several reasons not to use extension cords, your picture represents #1. The cords are bundled together & extension cords aren't rated for that. Too much heat for the insulation.

[wtd]

I use flexible cords, but wouldn't use it in a wall cavity as shown in the picture above. Mine run through compartments and in open air.
The insulation isn't rated for the temperatures that might be encountered in enclosed spaces carrying near max. current, and while it probably wouldn't really cause a problem in a wall with light loading, imagine one run just inside the roof, inside an enclosed ceiling, providing near limit current to, say, a roof air conditioner.

As to Fred Hobie saying

They are UL approved and very flexible.

well, flexible cords might be UL listed, but not for that application shown in that picture. You have to read what it's listed FOR and use the device or appliance in that manner. If an electric heater is UL listed, it's listed for use as a heater - it doesn't mean that you can turn it face up and cook breakfast on it and that's OK because it's 'UL Listed'. Have never heard of Fred Hobie, but looking at that picture I don't think I've really missed much.

Ah, bus-bro slid in ahead of me just as I was writing this - I agree with him.

Tom

[bus-bro]

wtd, you said it so well.

[lornaschinske]

Well, I DO know who Fred is. I WILL use our extension cords. Fred was kind enough to answer many of my stupid questions I posted years ago on the Coach forums. He has converted many coaches over the years and gives seminars.


Could you please tell me the difference between the 12 gauge stranded copper wire in an extension cord and the 12 gauge stranded copper in a spool of wire?

David said to tell you that we certainly will not be pulling any more power thru the wiring than we already have using 12/3 extension cords on construction sites. sometimes running 200 to 300 ft from a power pole (we used to run air compressors, table saws, routers, circular saws & drills. many at the same time. add a Ready heater or two into that in the winter). Did I mention we are currently running an electric heater on a 25 ft 12/3 extension cord? It's not even warm... the cord, the heater is warm!

[bus-bro]

Originally Posted by lornaschinske

Could you please tell me the difference between the 12 gauge stranded copper wire in an extension cord and the 12 gauge stranded copper in a spool of wire?

The two most important would be the rating of the insulation, and the number of strands per AWG.

[lornaschinske]

Since I have lived the the "wire wars" here's a blast from the past... http://www.busnut.com/bbs/messages/233/2949.html Nothing was really resolved but you can stop directing it at me.There is nothing you can say that I have not already heard and considered. Like I said, I will use the wire we have. I will sit down, strip it out of the sheathing and wire it from the panel box breakers to what ever it's powering. It's not like any of our cords are "cheap". We may have used contractor cords but they were the best we could buy. So just put my wiring in the same category as my GFI breaker (you know, the one that can't possibly work because the power pole has a GFI breaker in it). This is far from the first time we have wired using a heavy duty contractor cord. They never got hot. Unlike the original wiring.

[lornaschinske]

Originally Posted by bus-bro

The two most important would be the rating of the insulation, and the number of strands per AWG.

Our extension cords are heavier and have more stands then the spools of wire the are available from Lowes/HomeDepot. I have never seen anywhere any indication of what the insulation is made of.

[thommassey]

IMHO, insulation is EVERYTHING, along with heat, mechanical protection and load that MAY EVER at one time be on the ckt. Copper is expensive, but I have been on service calls more than once, when the cause of HEAT, not always a fire yet, were from improper use of wire (type of insulation, i.e. zip cord, extension cord, lamp cord, SO cord, etc.)
Places like wiring, I will try to install the SAFEST system I can for the money... I know little of buses and auto wiring, most I have learned in the past 8 months just reading here, but electrical systems will find a weak spot on there own, if one is available. Hell, a homeowner once used lamp cord for ten years inside a wall to a clothes washer, till the insulation finally gave up... they did live thru the fire. Just sayin, lots of stuff will work, but USE SAFE installs wherever you can.

[chev49]

estension cords are fine with me. its not a question of the cord, its how much load you place on it... either 110 or 12v... hence proper number of circuits. and as far as earlier post mentioned using them for 100 feet or more on construction sites... i used a 100' 10ga one to run a double wide mobile while i was putting in the electric, well and sewer, and it worked fine..just didnt start the electric furnace. My bus has extension cords for the 12v and solid wiring for the 110v, except for a few ends.. like to the frig.

[wtd]

As mentioned, it's all in how you use it -

It's this kinda mess that's scary.
I'm sure this installation is impressive in it's 'neatness', but that's it's biggest problem -


Let's try to put a breaker on one of those circuits
We'll assume they're 12 ga. and since we have no idea what type of insulation is on these cables (is it really 'SO' or what?) we'll calc a breaker using plain old THHN (90C/194F) -

12 gauge ampacity @ 30C = 27 amps. NEC Table B.310.1

This installation is right up against the metal skin of the bus (or nearly so) and will probably be filled with insulation and covered with a ceiling. Think it'll get hot in there? You betcha - think it'll get to 140F - wouldn't doubt it a bit. Next to a piece of heated metal and insulation to stop all air flow. HOT!

So let's derate our 12ga. wire again per NEC B.310.1 for the higher ambient temperature (140F/60C)-
27 amps x .71 = 19.6 amps

Now, I can identify at least 9 cables in this photo, there could be more - so 18 current carrying conductors -
So let's again derate once again, this time per NEC B.31..15(B)(2)(a) for multiple conductors in a race.
19.6 amp x 0.5 = 9.6 amps.

Where do you get a breaker for that?

[lornaschinske]

Since we have no DC on the house side (except the water pump and the 12vDC stuff for the hydronic system) we will be using the extension cords. For the 12vDC stuff I will use the unmarked wiring out of the Eagle (from Belgium). My opinion of the use of romex... let's just say, I'm not terribly comfortable with it.

But here is what I have come up with after cruising thru the internet. ..

Ancor/Marinco/Nicro
ANCOR's proprietary premium vinyl insulation stays flexible even in extreme cold and resists salt water, battery acid, oil, gasoline and ultra-violet radiation. Exclusive insulation is rated at 600 volts, 105° C dry and 75° C wet,

“Can I use ‘regular wire’ for my boat?” The answer to this common question is a qualified “yes,” if the wire is SAE (Society of Automotive Engineering) J378, J1127 or J1128. These wires are designed for “surface vehicles,” not for the special requirements of the marine industry, but meet the minimum standards for boats in limited circumstances.

SAE (Society of Automotive Engineering) wire is up to 12% smaller than AWG (American Wire Gauge) Boat Cable

Note: Ancor does not recommend SAE automotive wire to run 110vAC current. I'm running 110vAC current.



MY Contractor cables (interior wiring seems to have no markings on them.
E64047/16-3 SJ1W FT-2 (UL)(75C)C(UL)(60C)
25 strands

E64047/16-3 SJTW FT-2 (UL)(75C)C(UL)(60C)
25 strands
Note: The #16 gauge wire is rated to carry 13 amperes (up to 1560 watts for runs under 50 ft.If the cable length exceeds 50 feet, it will only have 1250 watts of available power. David & I tend to use these to replace the always too short cords on power tools after they break off. I have an electric staple gun with a cord that is all of 4" long. What are these people thinking.

#12 Style SJT 3-CONDUCTOR 100% COPPER
25 strands

Eagle Bus wire... I have been told buy other Eagle owners that this is identical to Ancor wire.
No markings
12 ga @ 35 strands

http://www.buyextensioncord.com/exte...ds_codes.shtml
The Jackets of extension cords are covered with imprints or embossing indicating how and where they can appropriately be used.It is essential to choose the correct cable jacket if you plan to use the extension cord in a demanding environment.

Here's the key to some of that code as outlined in the National Electrical Code.
S Hard Service Flexible Cord
SJ Junior Hard Service Flexible Cord
E Thermoplastic Elastomer Insulation
T Thermoplastic Insulation
O Jacket is Oil Resistant
OO Jacket & Conductors are Oil Resistant
R Thermoplastic Rubber Insulation
X Cross-linked Synthetic Polymer Insulation
HH High Temperature
W Moisture Resistant
N Nylon Jacket

http://www.ul.com/global/eng/pages/o...tsafety/cords/
Extension cords are labeled with valuable information as to the use, size and wattage rating of the cord. Cords are offered in many lengths and are marked with a size or "gauge." The gauge is based on the American Wire Gauge (AWG) System, in which the larger the wire, the smaller the AWG number. For example, a 12 gauge wire would be larger and can power larger wattage appliances than a 14 gauge wire.

Voltage x Amps = Watts or every 600 watts equals 5 amps (120 x 5 = 600) motors that need a surge (like refrigerator compressors) need a starting surge of up to 3X their running power. This is a general rule not a hard and fast fact. Some appliances require more, others less.

Any 16 gauge cord between 0 and 100 feet long will adequately handle loads up to 10 amps.
Any 14 gauge cord between 0 and 50 feet long will adequately handle loads between 10 and 15 amps.
Any 12 gauge cords between 50 to 100 feet long will adequately handle loads between 10 and 15 amps.

Our bus is 40 ft. The AC/DC panel box is roughly 10 ft from the front of the bus. Allowing for the ups/downs/overs I'm looking at a max run of under 50 ft (for my computer) on AC power. I have learned (in years past) that using SAE automotive wire is not all that great for AC current. That is why we are using the Eagles 12vDC systems wire on all our DC stuff. We won't be using a single breaker, we will be using up to 7. But it's our "house" and we WILL build to the standards we feel apply. After all it's not our first. And please, NO ONE DO WHAT WE ARE DOING. Happy everyone?

If anyone has the ANCOR wire, could you please strip the insulation back and count the wires and post it along with the guage here. I could not find that info anywhere.

[wtd]

The most important aspect of wiring design is the environment of the installation - that's what just about everything is based on (see my previous post).

Originally Posted by lornaschinske

Any 16 gauge cord between 0 and 100 feet long will adequately handle loads up to 10 amps.
Any 14 gauge cord between 0 and 50 feet long will adequately handle loads between 10 and 15 amps.
Any 12 gauge cords between 50 to 100 feet long will adequately handle loads between 10 and 15 amps.

While this may a good rule of thumb when using an extension cord as an extension cord, supplying a circular saw in the garage or a weed trimmer in the yard, once you put that cable in a 2" high solar heated metal channel it's a whole different story, as the simple calculations above show. It's no longer an extension cord - it's interior wiring - and all the extension cord specs and references are irrelevant.

All that stuff from a website that sells extension cords is probably accurate as far as the website is concerned because they're selling extension cords.

Originally Posted by lornaschinske

We won't be using a single breaker, we will be using up to 7.

If you run the cables as shown in the Fred Hobie photo, 7 is worse than one. You'll have 7 circuits, each with a conductor amapcity of less than 10 amps, each breaker'ed for 15 amps - the conductors can fail well before the breaker trips, assuming 15 amp breakers are used, of course.

One piece of good advice -

Originally Posted by lornaschinske

And please, NO ONE DO WHAT WE ARE DOING.

Tom

[lornaschinske]

I'll tell you what. I won't give any more advice on electrical. How's than. Nor anything else.