input please

[30dayreviews]

Hello. Im rewiring my trailer that im building because I realized I made a mess of it and over did It last fall. here is what I have
WFCO 30amp
2 inside led lights on a dimmer
2 gally LEDs on a switch
1 max fan
1batery volt readout
1 cigarette and quick charger
2 outside lights
2 switches for outside lights.
I will have a couple 4 USB-style charge ports that will be run on their own line. Represented by the plugs on top of the image

I would like to minimize the power options im using from the back of the wfco so that I have room to expand in the future such as outside flood lights on a roof rack, and an inverter inside for the tv.

Will this layout work?
what size wire would I need to use? 16/14?
what size fuse would I need for each color

[Philip]

Those USB charge ports use power even if nothing is plugged in. Put a switch to control them. I have also seen reports of them dyeing early when powered constant. Find the USB chargers without that darned blue or green light. It is annoying at night having a blue or green light glowing in the darkness.

If your using blade type fuses about the smallest fuse you can get is a 5 amp. All your lights combined might use 1 amp max. Just use a 5 amp and don't worry about it. The USB chargers a 5 amp will cover them. That cig lighter plug is rated for 20 amp. Figure the amp draw on the devices you're going to plug into it and fuse for the highest draw device used on it.

[30dayreviews]

as far as I can tell the only thing that has a light on it is the dimmer for the lights as I was very careful not to get any with LEDs.
Good point on the USB outlets I will have to order more switches to accommodate the change and have them all or mostly all on an on-off switch.
the fuses I would be using are like what you find in the car. unfortunately most the stuff I bought does not say how many amps they use so hard to do the math but ill start out at 5 and see how that works out.
thanks for the suggestions.

[Philip]

If the lights are LED. You don't measure draw on them in amps. They rate them by milliamps. No more than you're showing for an electrical system. I bet everything powered up will be less than 1.0 amp total.

My first camper I built. It had 30' of under cabinet lighting in it. This was the high output led string lights. With everything turned on including the TV. Total amperage draw was 2.0 amps.

Just make sure your wiring is rated for more than a 5 amp load. If you have a short to ground the fuse will blow before the wiring smokes.

[wannabefree]

Will this layut work? YES

A rule of thumb for fuses is figure out your max load and double it.

Wire size for low voltage DC systems is not as easy as for house wiring. Line loss becomes much more important because a few volts dropped across 20 feet of wire in you 12V system may mean things don't work, at 120V a few volts is pretty much a don't care. That said, I'll give you a couple "no thought" tips:
1) Don't use anything smaller than 14ga. It may seem like overkill, but if you want to squeeze efficiency you need fat wire. It is also less likely to convert itself to smoke, or heat up your walls and burst into flame.
2) remember that if you run 10 feet of duplex wire (red-black zip cord) you have 20 feet of wire.
3) Once you know your loads in amps, you can convert them to an equivalent resistance using Ohms law: R = V/I. So, if you have a 10A load and a nominal 12V, you have 12/10 or 1.2 ohms for your equivalent load. Now go on the internet and find a wire table. It will give you a number that is usually expressed as ohms per 1000 feet of wire for different wire sizes. The one I use says 12ga is 1.6 ohms/1000 feet.
4) decide how much line drop you can tolerate. Let's say it's 10% or 1.2V. You can then determine how much wire you can run to your 10A load. If I drop 1.2V in line loss, I can calculate the resistance that would be as V/A = R, or 1.2V/10A = 0.12 ohms. Then it is a matter of dividing my line drop ohms by the ohms/1000 feet and multiply that by 1000 to find out how much wire I can run. So, (0.12 / 1.6) *1000 = 75 feet.
5) Personally I think a 10% drop in my walls it excessive and I use 5%, which reduced the run to 37.5 feet, and because it must go to the load and back to the battery it means my load can be about 18 feet from the battery.
5) It's fine to go with heavier gauge wire than you think you need; it's only a few $$ and may save you grief later when you decide to add that killer radio you've been eyeing.
6) while you're pulling wire it is a good time to pull some extra for solar panels, stereos, and death rays, even if you don't think you have a use for them now.

[troubleScottie]

add a separate line dedicated to the fan, big draw.

A simple fuse box ( 1 power in/out to 6 fused lines ) would address a lot of issues. Yes, it is slightly more complex, but solves for any future expansions.