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Old 03-04-2018, 03:13 PM   #1
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bryan , TX
Join Date: Jul 2017
Posts: 2
Using existing 120v wiring for 12v system

New here and I can't seem to find an answer to my current question. First, let me admit this trailer is not an Airstream but it is a Streamline so it's pretty similar. The issue I'm having is that the trailer was built in 1960, therefore the 12v system is basically nonexistent. I have one small ceiling light and the old air compressor that pressurized the fresh water system. That's it. They both were powered by the tow vehicles 12v power source so no on board batteries or converter. While restoring the trailer I'd like to convert all of the lighting to 12v. I know 12v bulbs with a12 based exist also I'm thinking i could retain the original light fixtures by using those. Where my real question lies is whether or not I could isolate the wires that each light fixture is connected to, disconnect it from the breaker and wire that into a 12v system with a converter so I could also retain the already installed 120v plugs. Basically I want to retrofit the trailer with 12v without removing all of the interior skin. Thanks in advance.
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Old 03-04-2018, 03:42 PM   #2
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2002 30' Classic S/O
Melbourne Beach , Florida
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I'd be surprised if light fixture were isolated from outlets on a branch circuit from a breaker. You might have a mix of lights and outlets on one or more breakers. The only way to know for sure is to test with a meter or 120 outlet tester. If the trailer wiring is safe, you can power up the 120V and cycle breakers to see what is connected to each breaker. If you get lucky and only lighting is on a circuit I see no technical reason why you could not disconnect that from the 120V breaker and wire that circuit into your new 12V distribution. Airstream, along with many boat builders of that era used black wire for 12V and white for ground, similar to the AC convention where black was hot and white was neutral. I would seriously consider changing the fixtures however, to minimize confusion and ensure availability of bulbs when you are out camping.

“You cannot reason someone out of a position they have not been reasoned into"
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2002 Classic 30 Slideout -S/OS #004
2013 Dodge 2500 Laramie 4x4 Megacab Cummins
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Old 03-04-2018, 05:31 PM   #3
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bryan , TX
Join Date: Jul 2017
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I guess I was brain farting and not considering that trailer are wired in circuits like homes are lol. Looks like I'll probably end up removing the interior panels... what's 5000 more rivets anyway!
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Old 03-09-2018, 09:23 AM   #4
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Fort Davis , Texas
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Don't know what your budget is and if you would rather spend more money instead of many man hours. This suggestion requires little or no circuit re-wiring.

Install a battery system, solar system, and an AC Pass Through (hybrid) Inverter/Charger. This will do the following:

1. On shore power or generator the Inverter/Charger will supply your AC needs and also charge your batteries and supply any DC needs.

2. When no external AC is available the inverter/charger will supply your AC needs and the solar system will re-charge your batteries. DC loads are also provided for.

This is an over simplified explanation, suggest you contact AMSolar and discuss with them. URL is: https://amsolar.com/

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