# 12 volt wiring Q?



## City Bound (Jan 24, 2009)

I have a question about running wires for 12 volt outlets. What kind of wire should I use and what gage? I only have to run the wires about 30 feet.

Another Q: Can I run a standard table light on 12 volt if I splice a 12 volt style plug on the electric chord and use 12 volt bulbs instead of 120's, or do I have to get lamp materials made only for 12 volt and build a lamp to run on 12 volt?


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## Harvey_Birdman (Jul 5, 2012)

I am not sure about the fist question, I have not done much dc wiring.

But I have used 12v light bulbs on my boat, and they don't pull much current, so you should be ok switching the plug. On my boat I just used 110v extention cords hooked to the battery to run my lights. That way I could still use 110v bulbs if i needed the lights for the camper.


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## City Bound (Jan 24, 2009)

harvey. I set up some solar panels to a battery and now I want to run some wires from the battery to 12 volt dc outlets in my living space so I can plug in 12 volt table lamps.


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## Harvey_Birdman (Jul 5, 2012)

Being in a living space I can see why you would want to make the plugs diffrent. I can't say about the wire size, but the lamp would work if you use a 12v bulb and change the plug to match the ones you are putting on your 12v system.


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## Harvey_Birdman (Jul 5, 2012)

It would appear (from a google search) that the size of wire needed varies greatly depending on how long the wire needs to be. Here is a link to a chart I found.

http://sterling-power-usa.com/images/products/detail/A2BWireGaugeChart.3.jpg

ETA: Being in NYC you may want to check with the local fire marshell. There may be laws on what you have to use.


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## Gray Wolf (Jan 25, 2013)

Careful! It can be done correctly, with proper plugs and wire size, but be sure you follow electrical codes so you don't void your insurance policy. Our house is off grid and we had to support what we did to the state electrical inspector since DC wiring isn't "cookbook" to them. Switches and circuit breakers need to be DC too as DC doesn't "turn loose" like AC does. We found it easier/cheaper to wire our house for normal 120 AC and only run 24 volt DC for the solar panels/charge controller/inverter and 7 ceiling fans.


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## City Bound (Jan 24, 2009)

What is a book book to learn the basics of setting up a simple 12v system? I was looking at the book 12v Bible For Boats? Is that a good start?


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## 12vman (Feb 17, 2004)

Here's another wire loss chart..

http://www.affordable-solar.com/Learning-Center/Solar-Tools/wire-sizing

I use cigar lighter jacks as my outlets for any current draw under 5 amps. Anything higher than that gets a better connection, usually hard wired and fused at the source..

I run my power directly to all of my D.C. lights and use a relay at the fixture to save wire length. (Relays are cheaper than wire) I run phone wire from the relay to my wall switches to turn the lights on/off. The current draw to operate the relay is milliamps compared to the draw of the light fixture itself. Standard A.C. wall switches will last for years..


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## City Bound (Jan 24, 2009)

12 man, phone wire is thick enough? I want to use the cigerette lighter sockets. They sell those sockets on amazon. 

12, what I want to do is set up a small fuse box from my battery bank and then run two wires from the fuse box to two seperate outlets. All I would be running on the outlets would be two 12 volt dc table lamps and maybe a 12 volt dc fan in the summer. I am not really sure how to do all this. Do you have any suggestions?


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## 12vman (Feb 17, 2004)

The phone wire is only used to operate the relay from a switch, not to carry the power to the device. The relay is what switches the power to a device, not the switch itself. The switch only controls the power to the coil of the relay to activate/deactivate it, which is very low current. 

The shortest distance between two points is a straight line. You can run power directly to an item (light, pump, ect..) without the need of running one of the power leads to a switch to turn it on/off, to avoid adding unnecessary wire length. A relay can do the switching at the item but you can control the relay with much smaller wire. (Phone Wire works well even at 100') 

http://www.wisegeek.com/what-is-a-power-relay.htm

These are the outlets that I use around here..

http://www.able2products.com/Update/14_0553_v1.htm

Make one run from your battery to one of these and you'll have 3 outlets. Add a 5 amp fuse inline at the battery and you should be good.. (No need for a fuse box) Use one of the above line loss charts to figure the gauge of wire that you need. (For the distance between the battery and the outlet(s).


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