Running wires from Tongue box to cabin(AC & DC together)

Anything electric, AC or DC

Postby MceeD » Fri Apr 02, 2010 11:14 pm

Beautiful use of Smurf Tube Mr. Wood Butcher.
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Postby Woodbutcher » Sat Apr 03, 2010 11:33 am

Thanks, it has already paid off as I have added a few wires to the project.
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Postby dh » Fri Apr 16, 2010 11:22 pm

Miriam C. wrote:
SmilinJack wrote:Don't use wire ties. They will eventually break. I did that on a small utility trailer and was constantly having to get under it and replace the wire ties. The box stores sell metal "C" type clamps (can't think of the name of it) that has a hole in it that you screw to wood to hold conduit. I'd use those...


:thinking: Well the metal gives me the willies but there are wire holders that screw into the frame and hold wire that are plastic. Mine is done that way.

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They also have metal with a rubber inside. Box stores have them as well as hardware stores and maybe auto parts stores.


A metal pipe bracket on a metal pipe or conduit will be ok, but for an SO type cord, the plastic ones Miriam pictured are the way to go.

Also, I do not trust screws to hold these to the frame. I prefer rivits.
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Postby bobhenry » Sat Apr 17, 2010 12:00 am

Newman39Fan wrote:This now makes no sense to me. With the small space of a TD, I can not imagine not running AC and DC wires next to each other. In the Gen Ben plans, and I have seen a lot of people use this, there is a raceway for all of the wires - AC and DC all mixed. So if this has not caused a problem for all of the TD's on the road, how will running an extension cord in the same tube as the Battery wires cause this big of an issue?


Man I found this and I will say it again ......

And if you use 120 volt 2 wire extention cord for your DC It should be rated high enough to survive?

I have ran 220 440 660 explosion proof in chemical enviroments and many ran the 120 ac switching circuits in the same conduit. The continued berating of this electrical falicy is a continuing source of amusement to me. I have 120 volt ac and 12 volt dc in the same lamp ficture and they have somehow survived without cremeating me in my sleep for over 2 year. If you have fused the 12 volt dc and the 120 volt ac is protected you will probably survive the night. Let's no scare the kids with these fairytales.

I have built many dual voltage fictures and they continue to serve after 2 years of camping. Just fuse each properly and you will live to tell the tale


It has been pointed out before every lighted exit sign in hospitals schools nursing homes ect are dual voltage. There is 12 volt emergency back up with 120 ac for standard operation. So it is possible for these 2 beasts to be in the same cage :thinking:

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Laugh if you want but I used vacuum sweeper cord for my DC wiring for my lighting. I see a vacuum sweeper in the trash at the curb and I will hop out and cut off the cord for later use. They are 2 wire and generally are in 20 foot lengths. Yes my ac and dc run together I used 3 wire orange 12 gage extension cord for the ac runs as a visual aid to identify the ac from the black dc cords.
Last edited by bobhenry on Sun Apr 18, 2010 6:02 am, edited 1 time in total.
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Postby Miriam C. » Sat Apr 17, 2010 10:07 am

In my world there is a difference between what you run together inside a controlled area and what you run under the trailer where the rock, curbs and other hazards exist. My wires are in a plastic wire run inside and I expect no issues. Hope Murphy didn't hear that....... :cry:
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Postby zapj » Sun Aug 28, 2011 1:10 pm

I have had no problems with 120 and 12 being together either in conduit or in raceways.
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Re: Running wires from Tongue box to cabin(AC & DC together)

Postby Colemancooler » Mon Sep 03, 2012 2:40 pm

I am running a ground wire for all of my trailer operating lights (stop tail and turn}, can I tie my auto lights ground and my accessory lights into the same ground strip in the trailer ?


on a separate note i have seen 120Vac wires cross over a miniscule amount of voltage into 24V control wiring, but never enough to cause a problem. when run in close proximity
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Re: Running wires from Tongue box to cabin(AC & DC together)

Postby ewdove » Fri Jan 18, 2013 5:43 pm

Being very late to the discussion is peripheral.

The main reason to not run AC and DC wires in close proximity is that the AC current can cause induction in the DC wires, thereby altering the DC voltage significantly and creating potential hazards. Feeding more than 12 or 15v DC into a device expecting only 12v DC can not only damage the device but cause overloading of critical components, arcing and even fire.

Induction is how people steal electricity from high-power wires - all you have to do is run a conductor parallel to the wires and properly regulate the resulting voltage. It helps if you can wrap your wire around the high-power wire rather than just run parallel, but parallel works.

Way back a couple of decades ago I was attempting to diagnose sporadic failures of a thin ethernet network in an office environment. When I disconnected one of the two loops from the server I got a significant jolt - shock - from the two components. I had an electrician measure the differential between the thinnet ground and the server chassis, and it was 48 volts. 48 volts?!?

It turned out that they had previously coiled a length of the ethernet cable in the ceiling and placed it on top of a fluorescent fixture. Those fixtures contain ballasts that convert 120v AC into the current needed to illuminate a fluorescent tube. The currents in the fixture were causing induction in the shielding of the thin ethernet cable, thus creating the 48v differential to the server (and, consequently, the sporadic failures.)

Rule #1: Do not underestimate the ability of AC current to cause unwanted induction, especially in DC circuits. "Static" on an audio system is a symptom.
Rule #2: Do not underestimate the ability of unwanted induction to cause all manner of problems in your DC circuits, such as over-voltage that can damage DC systems and create hazardous conditions.
Rule #3: Keep AC and DC as separate as possible.
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