Wiring a campervan

Phase one of the campervan wiring is now complete – hurrah! There is finally a light at the end of the tunnel. Actually there’s not because lighting is part of phase two, but at least the fridge is whirring away nicely.

What follows is a very simplified description of how we got to this point. If you have any more detailed questions, please leave a comment at the bottom of this post!

<Disclaimer> Now, I am (clearly) not an electrician and neither, for that matter, is Paul. All the works described below are still to be certified by a licensed electrician to ensure we’re in no danger of electrocution down the track.

Okay. We have two main circuits: One that will plug into a 240v power source at a campsite, and one that is powered by a 12v battery for when we’re travelling off-piste.

Here’s an overall view:

240v power circuit

  • Paul cut a small hole in the shell of the van and attached a 240 socket so we can run a cable to an external power supply.

  • From the other side of the socket, a 2.5mm cable runs through a conduit (to protect from any sharp metal) along the inside of the campervan to a 16 amp fuse.

  • The fuse clips onto a small metal bracket, which is screwed to the van. The yellow and green cable shown above connects to the metal shell of the van (we had to scrape a small patch of paint off the interior) to provide the earth.
  • Three cables then run from this fuse. The first runs to a power socket for the battery charger – ours is a CTEK Multi XS 150000. The charger will eventually be hard-wired to the battery.

  • The second cable runs around the front of the living area, under the doorway (in the lower of two conduits) to the power point for the fridge.

  • The third cable will run to an additional socket. Perhaps for a hair straightener.

12v battery circuit

There are two circuits from the battery.

  1. The first solely powers the fridge when we’re not connected to external power.  The fridge will automatically recognise when we disconnect from the 240v, and will switch to battery power.

The cable runs from the battery to a 15 amp fuse, then through an isolation switch, around the front of the living area, through the top conduit in the doorway and to the fridge.

We used an 8mm diameter cable to prevent any voltage drop between the battery and fridge and it seemed to do the trick; even with a 4.5m cable, we’re getting a consistent 12volts to the fridge. In fact, we seem to have gained a few…

In this case, the van’s metal shell provides the negative connection to the battery. Very handy.

2. The second battery circuit will power all other elements, which we’ll install in phase two: the water pump, lights and extractor fans.

The cable runs from the battery to a 40 amp fuse, then through an isolation switch, around the front of the living area to the control panel. Each switch in the control panel has its own fuse, ranging from 10-15 amps.

We’ll use the control panel to switch on the lights, fans and water pump. The water pump sits to the left of the fridge, so the cable runs around the fire extinguisher above, through the top conduit in the doorway and past the fridge to the pump.

Isolation switches

Running the cables through an isolation switch means we can manually switch the circuit off if necessary. We have also installed a dual-battery isolator; the car’s alternator will charge our 12v battery while we’re driving, but the isolator prevents our battery taking power from the car’s battery.

So that’s it! We bought everything from Bunnings (surprise, surprise), Supercheap Auto and a local electrical shop. Phase two is to install the lighting and fans, which involves cutting a hole in the roof, yikes.


24 thoughts on “Wiring a campervan

  1. Very impressed!!!
    Keep up the good work.
    A friend wired up his camper tent with strip LED lighting. Can be made to any length!! Very compact, flexible and very bright. There is a LED light shop in Nudgee or on eBay

  2. Hey this is clever. I’ve spent some time trying to work this out in my (very non electrician) mind, eventually solving questions like why the fuse ratings for the lighting circuit need to be so high, and how you can earth the van’s shell and at the same time use it as the negative connection to the battery. Very impressed that you can charge the battery from the charger and from the engine battery. All sounds good. Lets hope the licensed electrician agrees!

    • Thank you! Yes I can’t admit to having thought those points through in very great detail but I presume Paul did, because they all seem to work!

  3. Hey there, Been having a great time reading your blog giving me ideas for my next camper project.
    Just a quick safety note on electrical. It looks like you’re using a Lead Acid Battery. Be aware that upon failure, these batteries are able to leak flammable gasses into the air. This is only a problem in enclosed spaces (such as a van).
    The two solutions are:
    1- Change to an AGM battery (These can be mounted on their side also, and have a much higher capacity as well as a better deep cycle ability.) Don’t get this confused with a “sealed” maintenance free battery. This type of battery is naturally suited to this sort of work. It can handle being discharged and then topped up repeatedly. A Lead acid battery will fail prematurely, and when it does, it has a high chance to leak gas. (Some also leak gas while being charged). A proper AGM battery will cost you more, but its the only one you should be using. An Auto Electrician should have advised you against your battery when he inspected the system (If you used a regular electrician, he would have no idea)
    2 – External Venting. Purchase a sealed battery box and then run a vent to the outside of the van. This I don’t recommend as it makes maintenance hard, and is still not 100% safe.

    I only know this as I’ve built a few vans before, as well as being dual qualified as an electronics technician (low voltage such as this) and an electrician (mains power).

    Feel free to shoot me any questions you may have.

    Cheers, Sam

    • Oh and I always install a smoke detector and fire extinguisher in my vans.. for $20, its well worth it. However they do not detect gases.

      • Hi Sam – thanks for stopping by! You make some very important points that everyone should consider when building their own van (our battery compartment is vented to the outside). And I’d always recommend fitting a fire extinguisher, gas detector and smoke detector in your van – just remember to always cook your steak on the bbq outside; I once tried to get away with frying it inside – the noise!!


  4. Hi Rachel,
    It’s very inspiring block, thank you!
    We are starting our own project.
    Just quick question: did you bought all kitchen appliances (microwave, coffee mashine etc) with 12V/240V like a fridge or just use normal 240V?
    Thanks a lot for the answer.


    • Hi Serge,
      Seeing as Rachael Hasn’t replied, I might chime in.

      Microwaves: Havent found any 12v units yet. Best bet is to get a low powered (700-900W) unit. This will keep your inverter from tripping out.

      Fridge: Few options here. By the looks of things, Rachael has gone for a 240v bar fridge. This is a great option as they work well, however can only be used while on site power. You can run them through your inverter but will flatten your battery in no time. You can also go a 3 way fridge (240v / 12v / Gas), these can get pretty expensive but are VERY versatile. I personally recommend a 12v compressor fridge. These are the most efficient on power when running off batteries. They are also the most spacious for their size.

      Coffee Machine: I dare say again this would be dedicated 240v mainly for site power only.

      Basically anything that involves heating something will use ALOT of power, so is often best left to being used on site power only… Either that or get ALOT of batteries, and a HUGE inverter

      • Thanks very much Sam, I missed this comment when it originally came through (sorry Serge!) We don’t have a microwave or coffee machine but our fridge runs off the 12v and 240v. When we disconnect from an external power source it automatically switches to the battery – it works really well.

  5. I have a quick question, I have bought an old camper van with 240 external plug, this just goes to fridge and two plug outlets inside van, problem is external plug was wrecked, I took it off and wires just hung there. 4 wires, normal – / + / earth and a wire connect to chassis. I have new plug but am confused as to the wire which runs from chassis of van. It is black, my thinking is it has to be wired to earth in socket and not the black wire. I think maybe the colour of wire is wrong. Should the earth wire from chassis go to earth or neutral (black) in back of new socket? In your pic it looks like the wire I have is wrong colour and the wire from chassis goes to join the earth wire in back of socket

    Great site BTW.

    • Not even kidding, get a pro to look at this David… Different types of wires use colours differently. (Also different countries have different rules)

      Black can be anything from Neutral to Active to Earth. Pick the wrong one, and you could do some real damage. RCD’s only protect shorts to earth… a short from Active to Neutral will see around 10-20A of death and destruction (it takes around 0.1A to kill you).

      Also remember if replacing any power points to get double pole outlets (necessary in campervans due to the earth isolation having no protection.

      A pro would not likely charge you much to wire this up. its a straight forward job, but if one thing is wrong, it can be deadly.

      • Thanks again Sam, sorry for missing your comment David. The electrics should be earthed to the body of the van (scrape a bit of paint away to get a good metal-to-metal contact) but I agree with Sam, if you’re unsure definitely get a professional to have a look.

  6. Pingback: Au revoir, madame campervan | The Campervan Converts

  7. You have done great job.
    I have a Kia pregio van and want to convert to campervan. Would you like to share your drawing and pictures of your job.
    I can follow your way step by step if you don’t mind.

    • Thanks Tony! If you flick back through the blog there are lots of pictures and step-by-step guides, just let me know if you have any specific questions! Cheers, Rachel

  8. here is a really basic question. Can I change a fuse and how do i do it? The power has gone but I checked both my power chords and they work fine.

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