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How-to Wire 12v Accessories in a DIY Camper Van Electrical System

The electrical system in a DIY Camper Van is a bit pointless if you don’t have anything to power, so let’s learn how to hard-wire plugs, fans, and other accessories into your camper.

Quick note before we get started.  This is just one part of an overarching “How to Install a DIY Camper Van Electrical System” series.  If you’ve just stumbled on this article directly without seeing that, there are likely some things we’ve already covered.  If you want to check out that step by step guide, you can do that here: https://www.explorist.life/diy-campervan-solar

Also, we have interactive solar wiring diagrams that are a complete, A to Z solution for teaching you exactly what parts go where, what size wires to use, fuse size recommendations, wire lug sizes, and all kind of other stuff to help save you time and frustration.  You can check that out here: https://www.explorist.life/solarwiringdiagrams/

12v Distribution Block

We already know that all positive wires need to be protected with a fuse. A 12v Distribution Block makes a nice, organized spot to make all of your accessory runs originate from:

12v Distribution Block

The 12v Distribution Block connects into your busbar and the one I like has enough spaces for 12 circuits and can power a max of 100 amps at a time combined between all the branch, or accessory circuits.

12v Wire Color

Power, Positive, and Hot (these all mean the same thing and can be used interchangeably) wires in 12v setups are typically red. Since you are likely starting this from scratch, I recommend keeping it consistent and going with red for the positive wires.

Negative and neutral (again, same thing) in 12v systems are commonly EITHER black or sometimes yellow. Keep it easy and consistant here and go with black for your negative wires unless you have a really good specific reason to choose otherwise.

Wiring 12v Plugs in a DIY Camper

12v Plugs will power any of your plug in devices such as camera battery chargers, phones, drones, and in some cases: Refrigerators.

Standard 12v Plug

On the back of the Standard 12v Plug, there will be 2 pins that you’ll attach your wires to with spade connectors.

Chaining Multiple 12v Outlets

If you want to chain multiple 12v outlets on the same citcuit, you’ll want to wire them like this:

If you decide to wire multiple 12v outlets in the same circuit, please stay aware of how many total amps you anticipate using in their ENTIRE cicuit and size your fuse and wire size appropriately.

I actually don’t like wiring multiple 12v outlets in series, personally. I prefer running 1 x 12v outlet per fused circuit from the distribution block.

Wiring 12v DIY Camper Van Accessories:

Most 12v Accessories can be wired using the exact same methods as described above. Fans, refrigerators, 4g booster, etc..

12v accessory wire

I’m a big fan of 12ga duplex wire for 12v circuits. It’s big enough for 95% of accessory circuits and when installed in lengths consistent with being installed inside a camper stays within the 3% voltage drop range even though, most of the time it isn’t necessary. It’s a red and black wire with high-grade, 105°C insulation contained inside of a white protective sheath

Now that you’ve learned how to wire 12v accessories and a distribution block, it’s time to learn how to wire lights and things that require switches.  In this next lesson we are even going to talk about wiring in 2-way switches so don’t miss it. Check that out here:

https://www.explorist.life/how-to-wire-12v-lights-switches-2-way-switches-in-a-camper/

Everything that you are learning here is put to use in our FREE Interactive Solar Wiring Diagrams.  If you haven’t yet, check them out as they are a complete solution for a camper van electrical system.  Check them out here: https://www.explorist.life/solarwiringdiagrams/

Remember, this is just one part of a full camper van electrical educational series.  To see all of the individual guides, click here: https://www.explorist.life/diy-campervan-solar

Finally, If you found this guide helpful, It’d truly mean the world to us if you’d share it with somebody who can use it, pin it to pinterest for later reference, or share it to a facebook group when somebody has a question about this subject.  Click the bubble in the lower right corner to subscribe to be notified of future updates and as always, leave any questions you’ve got in the comments below.


Max

Sunday 22nd of May 2022

Hi Nate, for multiple lights that are chained on the same fuse, are they as protected as if they were on different fuses? As you explained, the fuse needs to upsize to account for the combined currents. But for example, if one of the chained lights developed a bad electrical connection inside, would the upsized fuse be able to protect the troubled wire among all the normal lights?

Thanks!!!

Susan Shaver

Thursday 12th of May 2022

For some reason when they put solar on our camper and fixed the house battery to be charged by both solar and using alternator from battery, they didn't install any 12 volt outlets, only used the inverter and installed 110/120 outlets, so I had no way to use my 12 volt appliances. I have a little fridge/freezer, an electric blanket, a fan, and a Hot Logic Mini which are all 12 volt appliances. I do not want to waste electricity by going back down from the 110/120 which would waste electricity. I think I should have a fuse for each one of them, so i outlet per circuit.

Nate Yarbrough

Sunday 15th of May 2022

Darn! Sounds like a cool project. Good luck!

Shanna S

Monday 18th of April 2022

Nate, what are your recommendations for installing and wiring a 12V Dometic AC unit? I have the Lynx Distributor but all posts are accounted for with MPPT Charge controller, DC/DC charge controller, 12V distribution block, and 3000 Multiplus Inverter. Does this connect directly to the batteries after a breaker?

Kaileigh

Thursday 10th of February 2022

Hi! We are having issues finding Ancor duplex wire due to supply shortages and one vendor recommended Cobra. They seem to have the same specs, but wondered if you had any experience using Cobra or a reason for choosing Ancor over Cobra?

Thanks!

PJ

Saturday 29th of January 2022

Excellent information- I’ve been looking for something that is thorough and reliable! I will be purchasing your diagrams.

Elderly lady getting ready to do her own van conversion and I prefer not to electrocute myself or burn down my van!

I only wish you sold the wiring already lugged. I’m not a fan of doing all the crimping and heat shrink wrapping myself.