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Topic: Wiring color code standards in the TC 12 Volt system.

Posted By: Camper_Jeff_&_Kelli on 02/24/12 02:10am

Still re-wiring my TC 12 volt system with large 4 gauge wire for greater efficiency. It's a little confusing to see how things are wired as an untidy rats nest in the TC. The truck side of the charge system from the alternator has Red Positive and Black Negative. Then, inside the TC at the 12 volt fuse distribution panel, Black becomes Positive and White becomes Negative. The Negative side of the battery system is tied to a ground. Shore power ground is also connected to that ground bus bar. I think I will mark the Black wires that are functioning as Negative with White Tape to eliminate confusion. The 12 volt branch circuits from the 12 volt fuse panel are all red after each fuse and there is an 8 gauge black positive feeder powering all of those branch circuits. My Power Supply connections are marked Red Positive and White Negative. I will be connecting the power supply using Red Positive and Black with White Tape Negative.
I figure the basis for the confusion of wiring standards comes from the truck 12 volt system being considered an ungrounded 12 volt system and the 12 volt system in the TC being considered a grounded 12 volt system. The truck system can have red + and black - but the TC is required to be black as the primary + and red or another color as the second + or third +. So what we are doing is merging two systems meeting different standards. I will maintain the ungrounded automotive red +, black -, system with the TC batteries and the new Power Max BoonDocker 45 Amp power supply but where the TC Fuse Panel connection is, I will switch to the 12 volt DC Grounded standard of Black = Power 1, Red = Power 2, Next Color ETC... = Power 3, 4, 5...

Any corrections or suggestions are invited.

Here is the US NEC Color Code for 12 volt systems.

US DC power:
The US National Electrical Code (for both AC and DC) mandates that the grounded neutral conductor of a power system be white or grey. The protective ground must be bare, green or green-yellow striped. Hot (active) wires may be any other colors except these. However, common practice (per local electrical inspectors) is for the first hot (live or active) wire to be black and the second hot to be red. The recommendations in Table below are by Wiles. He makes no recommendation for ungrounded power system colors. Usage of the ungrounded system is discouraged for safety. However, red (+) and black (-) follows the coloring of the grounded systems in the table.

US recommended DC power circuit wiring color codes.

Function___________________________Label_________________Color
Protective ground____________________PG___________________bare, green, or green-yellow
2-wire ungrounded DC Power System*****AUTOMOTIVE*******************************************
Positive_____________________________L+___________________No recommendation (red)
Negative____________________________L-____________________No recommendation (black)
2-wire grounded DC Power System*****TRUCK CAMPER / RV*********************************************
Positive (of a negative grounded) circuit____L+___________________Red
Negative (of a negative grounded) circuit___N____________________White
Positive (of a positive grounded) circuit_____N____________________White
Negative (of a positive grounded) circuit____L-___________________Black
3-wire grounded DC Power System**TWO BATTERIES WITH CENTER TAP 12 V + CT, 12 V - CT, 24 V across two batteries in series**
Positive____________________________L+____________________Red
Mid-wire (center tap)__________________N_____________________White
Negative____________________________L-____________________Black

UPDATE< 03/01/2012:
Link to completion thread and other helpful information thread links.

UPDATE: 03/03/2010
I did a little investigating on the S&S camper and it looks like they followed the color standard for trailer wiring.
Trailer Wiring Standards.

Jeff

* This post was last edited 03/03/12 05:45pm by Camper_Jeff_&_Kelli *


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Posted By: WyoTraveler on 02/24/12 07:42am

House wiring black is hot white is ground and green is grounded at the box. They use red for the other side of hot when it is 240 vac. Normally in DC systems red is hot and black is ground. I haven't looked at RV wiring codes maybe they go with the house type wiring even on the 12 vdc.


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Posted By: Gripnriprod on 02/24/12 09:03am

WyoTraveler wrote:

House wiring black is hot white is ground and green is grounded at the box. They use red for the other side of hot when it is 240 vac. Normally in DC systems red is hot and black is ground. I haven't looked at RV wiring codes maybe they go with the house type wiring even on the 12 vdc.

White is neutral in house wiring. The distinction is it's 120/240 AC. The neutral is grounded at the service.


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Posted By: enine on 02/24/12 02:48pm

I've noticed a lot follow the trailer wiring "standard" of white for ground and black or red for 12v
http://www.etrailer.com/faq-wiring.aspx


Posted By: Camper_Jeff_&_Kelli on 02/24/12 06:12pm

enine wrote:

I've noticed a lot follow the trailer wiring "standard" of white for ground and black or red for 12v
http://www.etrailer.com/faq-wiring.aspx


It's interesting to see that there is yet again another standard that must be merged in with the other standards.

Automotive, Red positive, Black Negative.

Inside the RV for the circuits that serve the living quarters, it's a grounded system with Black, Red, Blue, etc,,, being the Positive and White being the negative or neutral and green being the ground.

Then the RV also has the exterior marker light, brake light system which goes back to either the automotive or trailor standard.


I received my new 45 AMP power supply today and just finished installing it. It fired right up and put out 13.71 volts unloaded. Then I switched on the batteries and it dropped to 13.5 volts. After about a half hour, the voltage came up to 13.6 volts. One thing I noticed is the static on my AM radio is horrible, allowing only the strongest stations to come in. FM works like a charm. The radio has always put out noise on AM but it's worse with the new power supply. It has always been really bad when the flourescent lights are on too.
I've got some more cleaning and routing of wire to do so I may try a couple things to quiet the system down.

I'll post pictures when finished.


Posted By: enine on 02/24/12 07:01pm

The trailer wiring is pretty close to the NEC 12v 2 wire grounded. I'm connecting mine via the 7 pin trailer wiring so I followed that standard, red positive and white negative, then the 120v stuff is black and white so that lets me tell the 12v from any 120v wiring (though I don't have individual 120v wires so it probably doesn't matter).
I used brown for all the marker then orange for various switched 12v such as overhead lights.


Posted By: Tamnative on 02/24/12 08:23pm

Regardless of how you wire your camper,If you make a diagram listing what the different colors do and attach it at your converter you will not have any problems. If you are like me it won't matter What the standards are as the next time you have to do something with the wiring you will forget or worse be unsure. I have done this with everything from the house to the car to the camper and have never had a problem.
If you have problems because you want to use the wrong color wire they make tape for that purpose that you use on each end. I also find it useful to get the tablets that have stick-on numbers for tracing out circuits.


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Posted By: Joners on 02/24/12 10:56pm

Tamnative wrote:

Regardless of how you wire your camper,If you make a diagram listing what the different colors do and attach it at your converter you will not have any problems. If you are like me it won't matter What the standards are as the next time you have to do something with the wiring you will forget or worse be unsure. I have done this with everything from the house to the car to the camper and have never had a problem.
If you have problems because you want to use the wrong color wire they make tape for that purpose that you use on each end. I also find it useful to get the tablets that have stick-on numbers for tracing out circuits.


Good advice! It's always nice to have a good and accurate map (ie; wiring diagram)


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Posted By: Camper_Jeff_&_Kelli on 02/25/12 12:06am

Joners wrote:

Tamnative wrote:

Regardless of how you wire your camper,If you make a diagram listing what the different colors do and attach it at your converter you will not have any problems. If you are like me it won't matter What the standards are as the next time you have to do something with the wiring you will forget or worse be unsure. I have done this with everything from the house to the car to the camper and have never had a problem.
If you have problems because you want to use the wrong color wire they make tape for that purpose that you use on each end. I also find it useful to get the tablets that have stick-on numbers for tracing out circuits.


Good advice! It's always nice to have a good and accurate map (ie; wiring diagram)


I have made a diagram of the new wiring setup. I also want to do the wiring in a manner that adheres to the appropriate standard. Staying with a standard convention makes it easier in the future for myself or the next owner to do things.
This has been a good project. I got aquainted with a lot of the inner workings of the electrical system.


Posted By: SoCalDesertRider on 02/25/12 07:51am

12 volts, DC
red: positive
black: negative

120 volts, AC
black: positive
white: neutral
green or bare: ground

120/240 volts combination, AC
black: positive
red: positive
white: neutral
green or bare: ground

240 volts and higher, AC, single phase
black: positive
white: positive
green or bare: ground

240 volts and higher, AC, 3 phase
black: positive
white: positive
red: positive
green or bare: ground

12 volts, DC, trailer highway light, brake and battery charge system
white: ground
brown: tail
green: right stop/turn
yellow: left stop/turn
blue: brake feed
red: 12vdc+ battery charge
black: accessory, not usually used, can be used for backup lights

I may have the left/right stop & turn colors reversed, green/yellow. I can never remember which is which. LOL

* This post was edited 02/25/12 08:04am by SoCalDesertRider *


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Posted By: Reddog1 on 02/25/12 10:24am

Only SoCalDesertRider has mentioned the brown wire in autos. I think under the dash, brown is used for negative. I think my TC Atwater water heater uses brown for the positive.

Wayne


Posted By: Camper_Jeff_&_Kelli on 02/25/12 01:43pm

Reddog1 wrote:

Only SoCalDesertRider has mentioned the brown wire in autos. I think under the dash, brown is used for negative. I think my TC Atwater water heater uses brown for the positive.

Wayne


Hi Wayne,
"ENINE" came across this helpful page on trailor wiring last night.
E-Trailor
The brown wire is power for the tail and running lights. Green is right stop and turn, Yellow is left stop and turn. White is still chasis ground or neutral. If there were an earth ground, I would think it would be green but there is no earth ground on the vehicle or trailor. An earth ground only comes into play with the living space and associated components of the TC/RV and is grounded through shore powers green ground. There may be grounding through the TC jack legs when extended. There can only be one actual path to earth ground in an electrical system when the neutral and ground buss bars are bonded together. The TC/RV electrical panel is considered a sub-panel to the shore power main panel. From what I've gathered from reading various articles and what I know about NEC electrical code, that single path to ground is provided by the earth grounding associated with the shore power.
I also read OSHA requirements for generators. They require a stand alone generator like what might be charging the camper not be earth grounded up to 5000 watts output. These are workplace regulations pertaining to the use of handheld drills, saws, etc. My thinking would be that you might not want the generator grounded as that could create a path to ground through a person holding a tool, through the person and the ground back to the generator. I don't see a problem with a ground at the camper though. If there was a ground fault, the path would be through the camper, down the jacks or a short rod in the ground for that purpose.
I think I'll try to find more information.

* This post was edited 02/25/12 02:01pm by Camper_Jeff_&_Kelli *


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