12 volt wiring size - Fiberglass RV


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Old 10-12-2020, 08:20 PM   #1
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12 volt wiring size

What gauge copper wire should i use to wire the 12volt system in my fiberglass rv lighting system.
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Old 10-12-2020, 08:53 PM   #2
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Basic lighting

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Originally Posted by The Cac View Post
What gauge copper wire should i use to wire the 12volt system in my fiberglass rv lighting system.
Basic lighting can run on 16 AWG and if you are using LEDs that's over kill.
I use 14 AWG just because you never know when you may add something to the line and it's stronger.
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Old 10-12-2020, 09:24 PM   #3
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Thanks much!
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Old 10-13-2020, 09:36 AM   #4
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I bought, and used, both 12 & 16 Gauge wire in running new or extended circuits in my Scamp. The 12 is for circuits that I might plug an accessory plug into. The 16 for LED lighting. Truth be told, the 16 probably would be plenty for everything but I tend to overdo sometimes.
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Old 10-13-2020, 09:39 AM   #5
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Thanks for the insight
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Old 10-13-2020, 09:56 AM   #6
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These responses are correct. It's all about the load that the wire will carry. If you look at the 12v wire used on your car starter it's very heavy gauge as compared to the wire feeding a light bulb. Both are 12 volt demands but the amperage is much greater on the starter.

Find out what the load will be and pick accordingly.
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Old 10-13-2020, 02:30 PM   #7
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#14 AWG wire is readily available because it is a standard size building wire and the cost is basically the same as #16 wire
Voltage drop is a concern but also is mechanical strength especially when subject to vibration .
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Old 10-13-2020, 04:35 PM   #8
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Stranded wire only

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Originally Posted by The Cac View Post
What gauge copper wire should i use to wire the 12volt system in my fiberglass rv lighting system.
Stranded should be used in mobile applications, solid is for non mobile applications. Stranded wire is flexible, where solid core wire can bend, but not over and over.
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Old 10-14-2020, 04:37 PM   #9
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I have this table in my Scamp electrical folder. It seems to be a great resource... Gotta love some of the Chinese lights that come with 22g wire and a 10a fuse...
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Originally Posted by AC0GV View Post
Basic lighting can run on 16 AWG and if you are using LEDs that's over kill.
I use 14 AWG just because you never know when you may add something to the line and it's stronger.
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Old 10-14-2020, 04:48 PM   #10
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Oops. Dont see the table attachment
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Old 10-15-2020, 07:09 AM   #11
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Wire Size Calculator

Hello,

Here is an on line calculator to help decide on wire size:

https://www.calculator.net/voltage-drop-calculator.html

Uncle Larry
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Old 10-15-2020, 01:56 PM   #12
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This what I use. Read the description and you will find the covering is superior to any vehicle wiring. Being stranded and 12 Gauge it will power anything you connect to it. As an additional step, i run it inside that coragated flexamle plastic conduti just to be extra safe.
https://www.lowes.com/pd/Southwire-2...oll/1000992064
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Old 10-15-2020, 05:27 PM   #13
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Quote:
Originally Posted by AC0GV View Post
Stranded should be used in mobile applications, solid is for non mobile applications. Stranded wire is flexible, where solid core wire can bend, but not over and over.


Why would it bend after installation? I notice that most if not all manufacturers use copper tubing for gas connections. How is that any different.
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Old 10-17-2020, 10:43 AM   #14
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Why would it bend after installation? I notice that most if not all manufacturers use copper tubing for gas connections. How is that any different.

What is called "Work hardening." If you have a piece of wire moving (wiggling) during transit, the copper wire can actually break. On my install, as I will have some higher amp items going in, I ran a 6ga wire pair from the battery to a fuse block under the bunks. From that point, I can run an appropriate wire for lights, the stereo, and the ham radio. Most of my wiring is 14 ga stranded wire, it is small and easy to conceal. My wife hates to see wires, so to make her happy, all is routed so as to be unseen. I have found that a couple of reading lights and some brighter lights around the Kitchen prep area are more than enough. For outside, all mine are solar charged except for the security lights. Those are motion activated lights that run off of 3 A batteries. Life is a month or so. Snagged those from a plant I shut down. One on each side will alert me if someone or something is wandering around outside.



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Old 10-17-2020, 11:22 AM   #15
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Don't forget the fuses

Remember the fuses are sized to protect the wiring. If an appliance or load fails (shorts) the fuse should be sized to blow before the wiring burns up. Do not want an electrical fire hidden some where in the walls or behind a cabinet somewhere. I use 20 amp for 12 gauge & 15 amp for 14 gauge. Probably over conservative.

My $.02 worth.

Dennis.
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Old 10-17-2020, 11:32 AM   #16
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What gauge copper wire should i use to wire the 12volt system in my fiberglass rv lighting system.

Well that depends on the current that would be carried. Looks like most trailers use 18 gage. Might go up in size if you can. Sure don't want to have to fix that in the field or do it again.

But make sure you use stranded wire AND not the stranded wire used for house wiring. It still is not designed for a lot of vibrations. Use wire that you can get from an auto store.

And I also solder all of my connections and then put heat shrink tubing over them.
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Old 10-17-2020, 07:52 PM   #17
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Originally Posted by Derswede View Post
What is called "Work hardening." If you have a piece of wire moving (wiggling) during transit, the copper wire can actually break. On my install, as I will have some higher amp items going in, I ran a 6ga wire pair from the battery to a fuse block under the bunks. From that point, I can run an appropriate wire for lights, the stereo, and the ham radio. Most of my wiring is 14 ga stranded wire, it is small and easy to conceal. My wife hates to see wires, so to make her happy, all is routed so as to be unseen. I have found that a couple of reading lights and some brighter lights around the Kitchen prep area are more than enough. For outside, all mine are solar charged except for the security lights. Those are motion activated lights that run off of 3 A batteries. Life is a month or so. Snagged those from a plant I shut down. One on each side will alert me if someone or something is wandering around outside.



Derswede


I have used the stranded wire for most of mine. I did use some romex to add an extra outlet. I can’t see how it can move if it is fastened down.
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