What gauge wire do I need...for fridge

Putting this little set up in the rear of the bed to plug in my Costway Fridge...passenger side bed box cubby. Question...what size wire should I go with? 12? 10? I'll be going right to my fuse block. Not a mathematician...looking to see what some of you did for your fridges.

Thx!

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Whats the amp draw from the fridge? 12 g is way overkill for the panel, but not sure about the fridge. I personally wouldnt trust that cigarette socket for more than 3-4 amps max.

 

I use 14 gauge wire for my fridge. I think that is even overkill. How long of a wire are you gonna have? Mine only runs about 3 feet from my fridge to my fuse block. The longer the wire the more impedance it will have, and will need to be a higher gauge.

Edit: @Rock Lobster is also right about the cig. lighter. I wouldn't trust it. My fridge also plugged in that way. It kept falling out on any kind of offroad, which totally defeats the purpose of the fridge. I also just didn't trust it with the power draw my fridge has (~ 4 amps). So I cut it off and got some quick disconnect plugs from Autozone rated for 6 amps. It is hooked up directly to my fuse panel.

 

Rock Lobster is. Correct, find out how many amps the fridge is drawing, then go from there

 

Here's a rough guide for 12V DC:

 

That fridge draws about 4amps. 12v/50w.

The distance is the critical factor. I tried using 12g for my Edgestar fridge(in truck bed) but there was noticeable voltage drop so I switched to 10g. Smaller wire is OK if your voltage is high enough, and your engine is on, but you will end up too low too fast just using your car battery.

 

OK...I think I'll go that route...quick disconnect plugs. I'll probably end up going with 10 gauge....it's going in the back of my bed, the fuse panel is up by the battery.

 

How did you actually hook up the fridge though, since the cigarette plug option is out.

 

You're going to have a hell of a time routing and terminating a 10 gauge cable. Your realize that's larger than the cable that feeds your full sized fridge at home, right? From bed to engine bay, 14 is slightly overkill, while 16 is just barely sufficient for a 5 amp draw. If I were doing it to my own truck I'd probably run 16, if I were installing on a friend's truck I'd give them the 14. Running anything bigger does nothing but lighten the wallet and add frustration during install.

 

10 is easy to route and terminate, buy the appropriate sized connector and use a good crimper, solder if you're extra paranoid. For that long of a run it's not a terrible idea at all. Also gives OP flexibility if he ever wants to expand down the road and change that run to a sub panel. A 15' run at 10 gauge is only suggested up to 20a, thats not all that much at all.

Also, your fridge at home is a terrible example, that's 120v AC, not 12v DC. Apples and bananas. And that cable at home has 3 conductors in it, most likely 12 gauge, not a single conductor.

16 minimum, 12 is better, 10 is even better. I'd put in 10 just to not have to re-run it in the future if my plans change.

 

Impedance is the total opposition to current flow in an AC circuit and is a combination of resistance and reactance (frequency resistance) from inductors and capacitors. DC voltage has no frequency.

 

I have never had a problem powering my fridge through a cigarette outlet. The plug has never come out even when slamming around offroad and never failed to provide enough juice. I used 10ga wire for mine with about a 15’ run.

 

It's all about the right tools. I ran 6awg and had no problem running or terminating.

 

I'm going with 10. Just to be safe. Thanks for the input.

 

Good decision, that’s what I was going to recommend.

Depending what fridge you have, it should have a voltage cut off where the fridge will shut off to preserve the battery. Too thin of wire will result in larger voltage drop, so the fridge will cut off earlier than necessary.

 

I use Anderson powerpole connectors on my fridge.

 

I haven’t had any issues with a cigarette lighter outlet in mine. Only time I had an issue was when I jumped my truck off a small ledge, launching my stove forward and shearing the fridge wire. Whoops.

$15 later for a new cord and good to go.

 

10.
Same suggestion.
Good choice.

 

Personally, I did 10ga off a circuit breaker under the hood to a fuse panel in the bed so I could power the fridge easily and have some USB ports to charge stuff. I had a cig adapter originally but that failed on my first trip so I just hard wired the cord to the fuse block. I plan to swap to anderson plugs at some point.

 

Here is the critical piece of information you need to know when choosing wire size: Voltage drop. Below is a calculator that takes the mystery out of the decision. I would not rely on wire size charts because most of them are based on a 5% voltage drop criteria or more. When they say "maximum allowable amps", that means marginal performance from the device. Some things will run OK on a 5% drop, but other things require better. For my wiring I size for a 2% drop. Many frig units have a low voltage cut out, that shuts off the fridge when it detects voltage below some level. It will be a bigger issue when the truck is not running since you are starting with the standing voltage of the battery. This could be 12V or less. When the engine is running, you have 13.5 to 14V from the alternator, so a low voltage cut out is less likely. Some items like headlights just get dimmer as the voltage drops. This is why so many people install upgraded headlight harnesses to bypass the wimpy OEM wiring.

Most people don't know how any of this works, so the best advise is to use the calculator below and choose the wire size that gives you a 2% drop. 2% will ensure that whatever you wire is safe and functioning at a high level. Going lower than 2% is a case of rapidly diminishing returns.

https://www.calculator.net/voltage-...ance=20&distanceunit=feet&amperes=5&x=51&y=17