Battery to camper positive wire gauge

Roger66

Senior Member
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Huntingdon
Does anyone know what gauge wire should run from the battery to the circuit breaker on my 2001 320sr? I know that 8 gauge is running from the converter to the battery positive that's about a 25 ft run. The negative is 8 gauge as well. Then there's the positive feeding the camper that appears to be a possible 12 gauge and the other negative appears to be a 10 gauge. I don't know if the previous owner changed the wire for one reason or another. Just seems to be a light gauge considering the load it would be carrying when operating the slide or when the furnace is operating.
 

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A #8 is fine I don't recall a #10 wire that sunline used, 12 is usually lighting/acc. White ground black +12. Wire size usually jump up in 10 amp loads Your #8 probable goes to the load center/converter feeding light etc. I don't know about the slide motor unless it alone is feed with a #10 wire. Furnace should run fine on a #12 the run is fairly short. Old wiring that has been tinkered is always suspect because any thing that worked after being twisted together the tinkerer became an expert because it worked and didn't set fire to any thing.
 
Does anyone know what gauge wire should run from the battery to the circuit breaker on my 2001 320sr? I know that 8 gauge is running from the converter to the battery positive that's about a 25 ft run. The negative is 8 gauge as well. Then there's the positive feeding the camper that appears to be a possible 12 gauge and the other negative appears to be a 10 gauge. I don't know if the previous owner changed the wire for one reason or another. Just seems to be a light gauge considering the load it would be carrying when operating the slide or when the furnace is operating.

The 8ga wire from the converter is the one that feeds everything inside the camper. The 12 ga black is probably the charge line from the towing harness. The wiring looks original to me and is the same on my Sunline.
Gary G
 
The red #8 (battery feed) runs from the inverter to the battery and the smaller gauge black is a short run just inside the camper to the circuit breaker under the bed so about 3 ft. Then from there who knows where it all goes.... It's been a while since I've crawled in and opened the cover to see what gauge runs from the circuit breaker back. I guess if I were to compare both wires into and out of the breaker and they are the same gauge that would answer my question. If the feed is smaller than I should probably install the matching gauge wire.
 
Gary G thanks. We must have been typing at the same time. 8 just installed a new inverter that's why I know what gauge the red wire is.
 
Inverter

Here is the reason behind changing the inverter and also there was a loose auto fuse connection on the board.
 

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Yeah I'm not a "tinkerer" lol if I am going to spend the time to work on something I do it right the first time. It doesn't make sense to do something haphazardly. Thanks Mainah for your input as well any and all advise is greatly appreciated.
 
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Wiring connections

I took some pictures of my junction box under the master bed and marked them up with what I believe they are. If my markup is correct then both the slide and the battery are on 30 amp fuses.
 

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Does anyone know what gauge wire should run from the battery to the circuit breaker on my 2001 320sr? I know that 8 gauge is running from the converter to the battery positive that's about a 25 ft run. The negative is 8 gauge as well. Then there's the positive feeding the camper that appears to be a possible 12 gauge and the other negative appears to be a 10 gauge. I don't know if the previous owner changed the wire for one reason or another. Just seems to be a light gauge considering the load it would be carrying when operating the slide or when the furnace is operating.

Hi Roger,

Something seems a little out of original in this pic. A few comments that will combine to your later picture.

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The 2 smaller black wires with the blue connectors laying on the battery tray angle iron, "appear" to be the qty 2, no. 14 awg, wires for the emergency breakaway switch. One of those smaller wires "normally" goes back into the 7 wire DOT cable junction box to tie into a 12 volt "hot" wire direct off the battery, the other small black wire ties into the "blue" brake wire on the 7 wire truck cable harness and the camper brake wires. Sunline used blue as the hot wire for the brakes under the camper.

The heavy red, and the heavy white, you called no 8 awg, do look original and are the 12 volt hot + and ground/negative -. The red 12 volt + hot would go up into the DOT box and then to the 30 amp fuse. Your other pics shows this.

In that same pic above, is a heavier black and a smaller white then the main Sunline ground wire. Those extra black and white"appear" to be extra and not original. Can't tell as your pic does not show where they go. Sunline in the year 2001 would not be running 2 separate hot and ground wires to the battery as part of the power converter tie in.

If your camper has a power tongue jack, then yes, that heavier black wire if it goes to the jack, all fits. The extra white, if it also goes to the jack as a ground, that fits too but many use use the frame ground. If you have a manual hand crank jack, and that extra black and white go into the camper, that "appears" to be a prior owner addition. Not sure at this point what it feeds, need more pics/info and search and destroy on your end.

To this pic, something is missing in this pic or hidden under the bundle we cannot see. Need you to have a look.
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What is missing is the no 14 awg black power feed wire that goes to the emergency break away switch. That small wire normally is tied to the battery hot red wire "before" the fuse. Which should be in that box. There is not normally a fuse in the emergency break way wire circuit. The blue brake wire from the 7 wire cord is also missing. That said, Sunline may have joined the blue 7 wire cable wire, with the blue brake magnets wire and the other downstream no 14 awg black emergency breakaway wire under the camper and not bring the blue up into the junction box. But the emerge- breakaway hot has to come from the battery red wire somehow.

See what is under the camper at the end of the 7 wire cable, and see if there is a small black in the box inside the camper that runs down under the camper to feed the breakaway wire.

I agree, your labels are correct in this pic, the truck charge line being a circuit breaker is "different" as Sunline used a fuse on the 2003 and newer campers and a 30 amp self resetting circuit breaker on the main power feed between the battery and the power converter. But, that may be a Sunline change that occurred over the years.
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Also, just and FYI, you used the words "inverter" which I think you are talking about is a "converter". A power converter uses 120 VAC and creates 12 VDC which is what power the camper 12 volt items.

An "inverter" uses 12 VDC to create 120 VAC to run 120 VAC items. Sunline normally did not supply an inverter, only the converters to create 12 VDC to run the camper items.

Hope this helps

John
 
John
The labels were my best guess at what was what. I assumed the circuit breaker is for the TV charge line. I do know that the breakaway works as it was just tested last month for inspection. I will dig into this some more when I empty out the items when we get back from our camping trip this coming weekend. It is very possible that the circuit breaker is for the power converter and I just assumed the red wires were the power converter since the red wire in the converter runs upfront.
 
John
The labels were my best guess at what was what. I assumed the circuit breaker is for the TV charge line. I do know that the breakaway works as it was just tested last month for inspection. I will dig into this some more when I empty out the items when we get back from our camping trip this coming weekend. It is very possible that the circuit breaker is for the power converter and I just assumed the red wires were the power converter since the red wire in the converter runs upfront.

While you are looking, see if you can see a rating on the side of the self resetting circuit breaker. They often print on them the amp rating.

The little black wire that feeds that circuit breaker, sure did not look like a 10 gage wire which 30 amps is what the converter/battery charge line would be. But maybe it is a picture anomaly. The wire bundle covered the black feed wire and it was hard to see.
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Sunline most always on the newer campers used heavy gage red as the positive battery to converter line. The slide drive motor, yes that was a black hot wire. It may just be, Sunline used the breaker on the truck charge line. It is not a bad thing, just different. The only down side I can think of being a breaker on the truck charge line, if it is trips you never know it and there may be a short in the truck or camper that keeps resetting. And the down side of the fuse, it blows and you never know the battery is not charging from the truck. Both are not ideal.


As FYI, here is what the 2004 and newer camper have in the 7 wire junction box. The box was moved to the header. The truck charge line had a 30 amp fuse in it. The battery to converter connection and the slide has 30 amp self resetting circuit breakers.

Here is a non slide camper.
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On a slide camper. It has the extra breaker for the slide motor.
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Breaker ratings
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