Wiring Diagram - Help Please!!!

[Tommy2tone_1999]

Here is the wiring diagram I plan to use for my TD build. I am a complete idiot when it comes to electrical work. Can you guys please give me a quick critique?

[Sonoma ZR2]

I'll print of your diagram and have an automotive electrician have a look at it. There are a couple places you might be able to use a smaller gauge wire. Also what are the amps required per device will help to provide the correct wire size. Also what size camper dimensions are you looking at.

[George Taylor]

IF you are going to have regular 120 volt outlets for coffee pot etc, you would not need anything larger than a 12 awg wire. You would need 12-2 nm(romex) for them. That way you can run a max of 20 amps.

[tony.latham]

I know close to nothing about 120V AC in trailers (I'm a 12V guy) but in a house, the outlets are wired with 12GA. I think you could back off on to 14 or 16 GA on your DC. My Fantastic Fan doesn't pull over 3.5 amps. I can't even measure the amp usage of my 12V LEDs and my gauge reads down to a hundredth of an amp hour.

(George snuck his post in while this was waiting for me to get done with dinner!)

Tony

[George Taylor]

he he! I am an electrician by trade. You can wire some outlets in 14awg wire in homes, but they are only good for 15 amps. Usual the areas that will have a greater load (kitchens, bathroom outlets, garage outlets, etc) will be on 20 amp breakers so you need the 12awg for them. In a house the cost adds up quite a bit, but the amount used in a trailer does not add much.

[MtnDon]

The wire gauge on the DC side depends on load, or actually load and distance run. The idea is to have as low a resistance in the wire chosen to minimize the voltage drop from battery or power converter to the light or other device. If we strive to keep the voltage drop to approximately no more than 3% the following examples may be a guide for a 12 VDC system...
2 amps, 14 AWG = 30 feet max; 12 AWG = 46 feet max; 10 AWG = 75 feet max
4 amps, 14 AWG = 15 feet max; 12 AWG = 23 feet max; 10 AWG = 37 feet max
6 amps, 14 AWG = 10 feet max; 12 AWG = 16 feet max; 10 AWG = 25 feet max

My calculator doesn't go to smaller gauge wire but you can see the relationship between gauges.

The DC wire gauge between the battery and the power converter will be determined by the total DC load and/or the highest amperage the charger can provide the battery and of course the distance between battery and power converter.

30 amps, 8 AWG would have a max length of 8 feet.

Length of wire is for the length of each of the two wires.

[Tommy2tone_1999]

I made a few changes based upon your suggestions and from Zach and a few others on a Facebook group. Here's what I came up with. How's this look?

[S. Heisley]

If your converter installation instructions tell you to use a specific gauge of wire to/from the battery, do not deviate from that as it could negate your warranties for your converter and for your battery, should anything go wrong. Stand firm on that and follow the converter instructions for that portion of your wiring.

A disconnect/kill switch to your battery, such as you are showing, is an excellent addition.

[kayakdlk]

My original wiring diagram looked similar to yours with different gauges and then when I went to figure out how much wire I needed for each size I found it was just easier and cheaper to buy a 250' roll of 12 gauge speaker wire from ebay and use it for all my 12 volt wiring. I cut up a 12 gauge 3 wire extension cords cut for the A/C. It was easier to route and work with than the stiff romex.

Dan

[bdosborn]

You've got your 120V circuit protected by a 15A circuit breaker so you can use #14 AWG if you want. Or keep the #12 AWG and use a 20A circuit breaker.

Devices that plug into cigarette lighters type sockets can be up to 20 amps, you should use #12 AWG and a 20A fuse for those.

Voltage drop isn't much of an issue in a teardrop if you use #12 AWG for up to 20A loads and #14 AWG for everything 15A and smaller. There really isn't a need to go lower that #14 as it's just makes for more kinds of wire to buy and I have a hard time working with little bitty wires. Besides, it's better to use a little more wire than you need to make sure that voltage drop and heat build-up due to routing inside insulated walls aren't an issue. Protect the #14 AWG with a 15 A fuse. The fuse protects the wire, not the load so don't worry about protecting the device. They should be equipped with an internal fuse if it's required anyways.

You can use a #10 wire and a 30A fuse for your battery wire if don't plan on using any inverters over 200W.

Think about a switch inside the cabin to turn the porch lights on. It's nice for when things go bump in the night.

Bruce

[Tommy2tone_1999]

Thanks guys!

Bruce, great idea on the inside switch for the porch light. Also, I plan to store the battery in the tongue box. If I went with an 8 Ga wire for the battery, would you still recommend a 30 A fuse. Again apologies for my ignorance. I figure it's easy to ask the stupid questions now than pay the price later.

[tony.latham]

"Think about a switch inside the cabin to turn the porch lights on. It's nice for when things go bump in the night."

Bruce is absolutely right...


The best ever, "Let's go campin' movie"

Tony

[Tommy2tone_1999]

Also, the thought occurred to me that may I need a 110V AC outlet to power an air conditioner, or is there usually an outlet on the meter at campgrounds? My camping to this point has all been primitive in tents (Boy Scout Assistant Scoutmaster)

[bdosborn]

The best ever, "Let's go campin' movie"

Hey there's a comic book too:



I've got the movie in my Amazon wishlist, thanks for the tip.

Bruce

[bdosborn]

If I went with an 8 Ga wire for the battery, would you still recommend a 30 A fuse.

You can step up to a 40A fuse for a #8 AWG (which is good for 40A BTW). You're converter has plenty of room for breakers, why not add a 15A breaker for the A/C? Then you only have to worry about one plug for the entire trailer.

Oh and I noticed something else, I assume the 30A breaker in the converter is for your shore power plug. I would change that to a 20A if you plan on using a regular 20A cord and plug for shore power. Otherwise you'll need to add a 30A plug with and with a #10 AWG cord. The 30A plug can make it a pain to plug in at home as you'll have to use a 30A to 20A adapter or add a 30A plug in your garage.

Bruce