12/3 awg or 14/3awg?

[taz2]

Fellow sailors, im.about to install electrical outlets on tmy boat. However I'm not sure if I should use 12/3awg or 12/3awg wire.

Which wire should I use?

Moe

[SY Harmony]

120v?
What amp circuit breaker?
14/3 is typical to 15a

[mvweebles]

Go with 12/3. Rated for 20A circuits vs 15A for 14/3. 14/3 would in all liklihood be fine, but not much of a penalty for 12/3 in terms of either cost or installation. And it's a one-time cost.

[Hartleyg]

Assuming you are talking about 120 V AC, 14/3 is good up to 15 amps, 12/3 up to 20 amps. Line loss will be less with 12/3, but for most uses (space heaters are an exception) 14/3 is fine. Do not use anything but pure copper/tinned copper. Aluminum will make you cray-zee.

If you are wiring a water heater, microwave or something that draws a lot of power, you might consider 12/3 just to reduce the voltage drop.



Don't forget to use GOOD fixtures! Those $.99 fixtures are NOT worth it in the long run


Hartley
S/V ATsa

[Striker]

Tinned marine grade stranded wire would be the norm. Untinned will work just fine as well if good enough is your aim.
I would also second, or third, whatever, the use of 12g.

[hjohnson]

As others have said, you might as well go for 12/3.

A few additional notes:

1. Use marine tinned, stranded wire. This will reduce the likelihood of it rotting away and causing a fire in the marine environment.
2. Use good quality tinned copper terminals for the ends of the wire, along with a high quality crimper. Unlike home wiring, you do not just go and stick the wire directly into the electrical device.
3. Whatever you do, do not use Marettes/wire nuts on a boat. They have no place in a marine environment. Use terminal blocks and similar to ensure proper connections.
4. Don’t forget proper circuit protection on your system. You really should have an ELCI breaker close (within 10 feet) of your shore power inlet. This will protect your boat, and also protect those who find themselves in the water around your boat in case something goes seriously wrong.

Remember, you’re doing electrical work in an environment that is hostile to electrics. You need to do things properly in order to keep your boat from burning down, or killing someone.

[NorthCoastJoe]

Ancor 12/3 and Ancor heat shrink terminals, using the right crimp tool too.

Also go with 20 amp outlets, they are higher quality. This is one place you don't want to go cheap. I have seen some very cooked wiring in boats. Go with the best you can it will last longer and you can sleep without worry.