How to Wire 120V AC circuits in a DIY Camper Van

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This blog post will teach you everything you need to know to hard-wire 120V AC outlets and appliances into your camper van.

What is an AC Outlet?

An AC (Alternating Current) outlet is the standard household outlet that you will find around nearly every house in the world. It supplies power to your various household appliances and gets it’s power from a breaker box. The breaker box in a camper gets its power from the Inverter by means of either the batteries or shore power.

What is the Difference Between a 110V and 120V AC Circuits?

The terms 120V and 110V in regards to an AC outlet are pretty much the same and can, for our purposes be used interchangeably. In houses, power is delivered to the house at 120V plus/minus about 5% depending on transmission losses in the wires on the power poles. By the time the power actually ends up at the plug, it could be as low as 110 volts depending on the aforementioned losses as well as various voltage drop. But… for our purposes… the terms 110V and 120V can be used interchangeably and understanding the difference is not that important.

How to Wire a 120V Outlet

When looking at the front of the outlet, there are two screws on the right and 3 screws on the left.

  • The 2 gold screws on the right are for the ‘hot’ wires (black).
  • The 2 silver screws on the left are for the ‘neutral’ wires (white).
  • The 1 green screw on the left is for the ‘ground’ wires (green or bare copper).

How to Wire Multiple 120V Outlets on the Same Circuit

Wiring multiple 120V outlets on the same circuit is as simple as wiring the outlets in parallel.

  • Connect incoming ‘hot’ wire (black) to one of the ‘hot’ screws (gold screw on the right).
  • Connect outgoing ‘hot’ wire (black) to the other ‘hot’ screw (gold screw on the right).
  • Connect incoming ‘neutral’ wire (white) to one of the ‘neutral’ screws (silver screw on the left).
  • Connect outgoing ‘neutral’ wire (white) to the other ‘neutral’ screw (silver screw on the left).
  • Connect the incoming, outgoing, and short jumper of ground wire with a lever nut (https://amzn.to/3idGMnv) and connect the jumper wire to the ground screw (green) on the bottom left.
  • *optional* Since stranded wire is recommended on mobile applications, ring or spade terminals to connect wires to screws are permitted.

How Many 120V Outlets can be on the Same Circuit?

There can be as many outlets as you like on a single circuit. The number of outlets does not matter. What matters is the total wattage of devices plugged into ALL of the outlets on the circuit.

Think of this like your house. In your bedroom, all of your outlets are very likely on one circuit. If you plug your phone into one, your TV into one, an air purifier into one, and a computer into another, everything is likely going to work just fine. BUT… if you plugged a space heater into two seperate outlets and turned them both on high; it will very likely trip the breaker in your breaker box. This is because you overloaded the circuit. This is, for the most part, the EXACT same concept in a camper van.

How Many 120V Circuits Can Be Installed In a DIY Camper Van

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There can be as many 120V circuits in your camper as your breaker box allows. If you are using the breaker box that is in the wiring diagrams here on EXPLORIST.life, you can have up to 6 individual branch circuits. Typically, I’ll see individual branch circuits planned like this (just as an example):

What Size of Wire is Needed for 120v outlets?

Unlike with 12V DC wiring runs, voltage drop is less of an issue and circuit amperage is limited to a max of 20A for the most part; so a full-on wire sizing calculator is generally not necessary.If a wire size is recommended by the manufacturer of a particular item (common for hot water heaters and air conditioners) use the manufacturer recommended wire and breaker size. Otherwise: use 12 gauge wire (12/3 Wire: ) protected by a 20A breaker.

WHAT Type OF WIRE IS NEEDED FOR 120V OUTLETS In a Camper?

ALL wire in a camper must be stranded wire. This includes circuits for 120V outlets. Wires in a camper must be stranded wire (Like this: https://amzn.to/3im3aer) because solid core wire (like the Romex used in the walls of your house) will, when subjected to the vibrations of rattling down the road, will work harden and break over time. For this reason, solid core wire like Romex is EXPLICITLY forbidden in marine applications (boats) by ABYC E-11.

How to Wire 120V Outlets to the Camper Van Breaker Box

The 120V outlets in your camper van need to get their power from a breaker box. Here is how to wire the 120V circuits to the camper breaker box:

  • Connect the ‘Hot’ (Black) wire to the breaker
  • Connect the ‘Neutral’ (White) wire to the Neutral Busbar
  • Connect the ‘Ground’ (Green) wire to the Ground Busbar.

This concept is covered in much greater depth in the following blog post and video: https://www.explorist.life/how-to-wire-a-power-distribution-panel/

11 thoughts on “How to Wire 120V AC circuits in a DIY Camper Van”

  1. Hi Nate,
    Great info here, thanks for this! I was wanting your opinion of using 12/3 extension cords for the wire used on the outlets? Seems like it would be fine but wanted to get your input.

    Thank you!

    1. Jim (master electrician

      A 12/3 cord will carry 20 amps without issue but insulation on a typical extension cords is not rated to be hidden behind walls and it does not stand up well to UV, chemicals and moisture.
      Go to your local home center and pick up some 12/3 SOOW cord. It can be purchased by the foot. It is service rated, oil resistant (outer and inner jackets), weather resistant.

  2. Hi Nate
    Hope you are well.
    Total beginner here. I purchased the diagram for the 3000 watt inverter – 400 battery – 400 watt solar. I purchased all of the parts you recommended. However, before I purchase 6awg blk/red cable, i have some 4awg blk/red cable which is bigger. Is it OK to substitute that on each place you have 6awg blk/red listed? Are there some placed where that is not recommended?
    Also, is it OK to have only 3 battle born battery bank instead of 4 until I can save to purchase the last one?
    Scared to death about all of this because I have NEVER wired anything in my life – but your diagrams are great and you only live once, right?
    Sincerely
    Laura

    1. Generally substituting 6 AWG for 4 AWG won’t work because the wire will be too big to fit into the terminal of the device; but feel free to check the user manual of each device you are trying to alter the diagram for to see what is the max wire size the manufacturer recommends.

      Having 3 batteries is fine. 🙂

  3. Hi Nate,
    Thanks for the great info..
    I like your breaker box a lot but can’t seem to find the same one when I when I hit the links.
    Any suggestions as to the source? Hopefully it wasn’t right in front of my face!
    Thanks ,
    Rick

  4. Thanks so much for all the info on here. Curious (and perhaps this is covered in another post I haven’t seen yet), does the high powered outlet need to be connected to the three high power screws on the inverter ? (As opposed to through the breaker? And/or is the distribution box supposed to be connected to those somehow?
    Thanks!

  5. Hi Nate, great information here. I am trying to avoid propane in my van build. Can I use a 240 Volt tankless water heater with a 3000 watt inverter? Can 240 volt appliances be used in a van? If not, can you recommend a high quality tankless water heater at 120 Volts? Thanks.

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