Wire size?

[Somers]

Just received a Alpicool CF45 Fridge, when I wire The cigarette lighter plug-in for the fridge, I have about 12 feet to go to my fuse panel. It says the fridge draws 3 A. Is 16 gauge wire sufficient and a 5 amp fuse? No information about this came with the fridge. It is just a normal cigarette plug-in with USB ports in the other side of the panel.

 

[bass_sears]

Just received a Alpicool CF45 Fridge, when I wire The cigarette lighter plug-in for the fridge, I have about 12 feet to go to my fuse panel. It says the fridge draws 3 A. Is 16 gauge wire sufficient and a 5 amp fuse? No information about this came with the fridge. It is just a normal cigarette plug-in with USB ports in the other side of the panel.

12v 3A @ 16' on 16awg wire leads to 2.41% voltage drop:
https://www.calculator.net/voltage-drop-calculator.html
... which is within the desired 3% voltage drop for electronics (some people say you can get away with larger voltage drop for electric motors, but I don't know how I feel about that, and 3% is what you want to stay under for anything sensitive). Personally I'd go 14 or 12 just for efficiency but I over do things a lot.

As far as fuse, most electronics have internal fuses to protect the equipment, so the fuse on the wire is actually there to protect the wire not the equipment. Various charts out there disagree, unfortunately, and for 16awg wire it looks like max amperage is somewhere between 7.5A - 15A:
https://www.oznium.com/blog/how-to-determine-the-fuse-wire-size-for-your-project
https://www.engineeringtoolbox.com/wire-gauges-d_419.html

Regardless, a 5A fuse should protect the wire very effectively, and assuming that 3A is the max the fridge ever draws (no larger draw on startup?) then 5A should protect the 16awg wire and still not blow when the fridge starts up. If you want peace of mind that it's not going to be too sensitive you'd be fine with a 7.5A fuse too.

-- Bass

 

[B and C]

According to the Blue Seas Circuit Wizard, this should be OK.  A 16 GA cable can be fused to a maximum of 7.5 amps.

 

[Somers]

Ya know I was trying to find info on the starting up draw but this company is making it very hard to find much detail.
Thanks to both of you.
So nice to have a group of folks who help with this stuff.
I’m finding the electric side of van build a real challenge,
JIM
WELL THE WHOLE THING IS A CHALLENGE!

 

[B and C]

If it blows you're 5 amp fuse, put a 7.5 amp fuse in (no bigger).

 

[B and C]

If you are pinching pennies, use 16. If you are trying to future proof at all, a 14 or 12 GA cable could be used. If later you need a light or some other light draw (fan?) near where that larger wire is, you could tap into it and not have to run another dedicated branch circuit.

 

[Weight]

Get rid of the cg plug and hard wire the fridge to a fuse block. Run a heavy cable to the fuse block.

 

[B and C]

Number of cores in a wire determines amperage as well as voltage. There is confusion out there. I hope you are not using 16 Ga household wiring from the hardware store but automotive grade multi strand copper wire from an auto parts store or marine place. A solid core wire will carry more amps than a stranded core wire.

Working with 12V DC, use sources that use 12V DC. Electricians rarely touch low voltage stuff except for alarm panels and phone cables. I have followed some and had to redo the telephone portion.

 

[Weight]

The capacity of a wire depends on so much more than if stranded or solid core. Lets stay safe with electricity. Always use a wire chart for whatever grade wire you are using. I recommend marine grade, made in USA. But any stranded wire is good if the grade of wire matches what you are using. Again always consult a wire chart and look at voltage drop to select wire size. Then size your fuse to the ampere rating for your wire size. There are two standards in USA for mobile use, AWG and SAE. They differ in cross section. There are many temperature standards for the insulation coating. Marine is 102 C. I know many that use 14 awg zip cord, aka lamp cord or speaker wire. If the use is very low current it is fine. If solid copper. Much is aluminum with copper plating.