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Electrical Wiring in the Home/Electrical Retrofitting a Travel Trailer


Fuse Box
Fuse Box  

Hi Greg, Thanks for making yourself available. I have a 1950's era Terry travel Trailer. It it parked permanently in my yard and I use it as a guest room. I have a outlet box with standard 110 power and thus far I've just been running an extension cord in to power a lamp and coffee maker. I want to connect the existing wire in the trailer to the outlet so the built in interior lights function. The wiring is in good shape (insulation not frayed, etc.) but it's just two wires in the insulation without a ground wire. All outlets (two, 2-prong non-grounded plugs) and lights (three single bulb) are connected through a 30 amp fuse box (photo attached). The wiring runs to a connection under the trailer that I have been unable to identify online or by taking the photo into RV parts stores. It's a two prong system.  (photo)

Should I:
A) use the existing wire and an electrical conversion kit sold at RV stores to hook up the system, or
B) run new romax from the base of the fuse box and connect to the outlet box under the trailer., or

Any thoughts you have would be greatly appreciated.

With an older trailer the question you have to ask yourself is how far do I want to go with this upgrade.

The first and foremost thought is safety.

My thoughts are if this is my trailer and it is used as a guest room, I am going to ground the outlets and either convert the lights to 12 volts or ground them as well. I would even use a gfci outlet or a gfci breaker for the outlets.

Currently you have no ground protection, and the appliances are only protected in a short to neutral.

I would run a permanent cord from the fuse box, which I would turn into a breaker box, the cord needs to be 10 gauge and either ran in weather proof conduit, or an outdoor service type wire.
Then I would either hard wire into the breaker box on a 30 amp breaker, or I would install an outlet from the house connected to a 30 amp breaker (10 gauge wiring). The outlet would be the twist lock type. The cord from the trailer would also have a twist type connection.

Hope that helps.
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Electrical Wiring in the Home

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Greg Hughes


Troubleshooting electrical including appliances and HVAC.


34 years of experience.

Both college and tech schools in this field.

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