6 replies to this topic

[HappyCampers]

Hey folks,

I've used the search function here, but haven't hit pay dirt unfortunately. We purchased a Dometic CFX3 fridge during a hard to resist sale last month at REI. This will be replacing the original ice box and, while not a 'perfect' fit, it will occupy the same cabinet space.

My plan all along has been to install a female 12v socket in the cabinet and I picked up a single port ARB threaded unit for this. What I hadn't given much thought to is the wiring. Upon removing the ice box, I discovered that 4WC pre-wired the cabinet for a fridge (along with propane stub out).

There are three wires and I'm unclear as to what these are and if I can take advantage of these. I'd sure like to avoid the bodily contortions involved with running separate wiring. There are two 12 gauge wires (blue and black) and a single 14 gauge wire (blue). Can someone with solid knowledge on this tell me what these are?

My follow up questions have to do with wire size and fusing for this fridge. Assuming the 12 gauge wires are 12v pos and neg, is this sufficient or do I need 10 gauge here? Secondly, I'm wondering about fusing needs. Since this is pre-wiring for a fridge, is it safe to assume this is already addressed?

Your patience and helpful expertise are appreciated!

Chris

Edited by HappyCampers, 11 December 2022 - 08:07 PM.

[Wandering Sagebrush]

Chris, are there unused fuses or circuit breakers in your electrical panel?  If so, my bet is the wires may be terminated  there.  I suspect what you have iare 2 12VDC wires, along with a ground.  If you don’t have a digital multimeter, I think you would find it handy when determining where you have power, and which is ground.  Check your fridge documentation for amperage, it’s probably going to be less than the ampere pull of the 3way running on DC.  Your 12 gauge wires may be fine.

 

If the Dometic is AC/DC, consider running the fridge power cord to an AC outlet for when you’re on shore power.

 

Hope this helps.

[Vic Harder]

Wandering Sagebrush… did you mean to type 1A? I think the 3 way fridges pull a lot more on DC, more like 10A.

My DC only fridge pulls about 3A when running. The manufacturer used 10g on mine coming from the compressor, so I matched that, for a very short run of about 2’ to my fuse box. I suspect 12g will be fine. 16g (like on that green wire you posted a pic of) would not be.

[Wandering Sagebrush]

Wandering Sagebrush… did you mean to type 1A? I think the 3 way fridges pull a lot more on DC, more like 10A.

My DC only fridge pulls about 3A when running. The manufacturer used 10g on mine coming from the compressor, so I matched that, for a very short run of about 2’ to my fuse box. I suspect 12g will be fine. 16g (like on that green wire you posted a pic of) would not be.

Vic, I’m missing what you’re asking, but I do see a typo (iare) where I was debating the grammatical correctness of is or are. 
 

I completely agree the compressor fridge will draw mucho fewer amperes than the 3way, and that 12 gauge will possibly be fine.

[HappyCampers]

Wandering Sage & Vic,

Thanks to both of you for jumping in to help. Problem solved!

Your tip WS about going into the panel was immensely helpful. I'd never had need to 'wander' there. I had previously conducted an available voltage test with my multimeter on the 3 wires, but got zero volts. The label in the panel indicated a 12v circuit for fridge, but was missing the fuse (15 amp recommended). Theres also a 120 AC breaker for the fridge on the other side of the panel. After installing a 15 amp fuse, I tested again to find 12 volts available at the 12 gauge blue (assumed positive) and black (assumed negative). This is not a 12v DC color standard I'm familiar with.

I wired the new socket in and plugged in the fridge and all seems well. The ~4 amp draw on the fridge during the initial cooling down phase is consistent with what I've previously observed while plugged in to the 12v cigarette lighter socket. I'm letting it run through the night to make fridge and circuit continue to perform as they should.

Regarding shore power - there's a funky nuance (previous recall issue) on these CFX3 fridges. Although there are two separate AC and DC supply receptacles on the fridge and cords provided, you can't have both plugged in at the same time. Since we almost never use S.P. and the fridge sips energy, I switched the breaker off so that we don't run up against this issue. Not totally sure this matters, so just playing it safe. Again, not sure why it was on in the first place since the camper has never had a fridge.

After a successfull dryer rebuild yesterday and now this seemingly working correctly, I'm calling it quits while I'm ahead.

Thanks again for your willingness to help!

Edited by HappyCampers, 12 December 2022 - 01:20 AM.

[Wandering Sagebrush]

Chris, cool beans!  I’m glad that was helpful.  Did you check the 14 gauge wire for power?  I puzzled that for a bit, but tumbled to it is possibly a potential power source for a small computer fan to help cool the compressor.

 

A definite maybe…

[HappyCampers]

The smaller wire was still not getting voltage, so not sure?

I can see from my Smart Shunt data that the cooler cycled on and off through the night with no hiccups. So, all is good! Surprised to see that it turned on as frequently as it did given the minimal difference between the cooler temperature setting and ambient temp