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

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

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

CLICK HERE TO PURCHASE THE HIGH RESOLUTION PDF VERSION OF THIS DIAGRAM

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/


Brandon

Wednesday 1st of September 2021

Hello - thank you for all of your super helpful information! I’m currently building out my ram promaster into a camper van. I have almost everything complete and about to start hooking up wires. However, I’m wanting to double check everything before I go through it all.

Do you ever offer services where I could pay you to review my layout of electrical?

Thanks!

Nate Yarbrough

Wednesday 1st of September 2021

Yep! More info on that: https://community.explorist.life

Callie

Tuesday 31st of August 2021

Hi Nate!

I purchased the PDFs for the wiring diagram that I need as well as the 120v AC circuits and the 12V branch circuit.

I know you mentioned that in the 120v circuit all the wiring used was 12/3, I was just wondering why it had to be 12/3 wire as opposed to just regular 12 AWG stranded wire?

I was also wondering about the 12v circuit. I didn't notice anywhere where it mentioned what type of wire to use then? I know sizing is explained in the PDF based on the amperage and the length but I just want to make sure I am also getting the right type of wire.

Thanks in advance!

Cat Richard

Wednesday 4th of August 2021

I did a similar wiring with the DC — with only a few things wired in a series, but most items running individually to the fuse block. So, I have so many items to connect at the fuse box. Can I put more than one connection together in the same fuse at the fuse box (like wire together the USB outlet wire with the wire to the bedroom Lights) and then attach that to one fuse?

Like I said, learning the hard way!

Thanks, Cat

Cat Richard

Wednesday 4th of August 2021

I’m new to this and I ran all the wiring with the outlets running parallel. Is there a way to connect this at the breaker box without having to re-wire everything? Can I get a bigger breaker box (with more breakers) or piggy back a second box? It was quite a lot of work to run all the wires to the back of the van individually. Learning the hard way!

Walter

Thursday 29th of July 2021

Hello! Great write up! Quick question: I have a 2011 Ford E350 Transit (w/Topper), there is a distribution panel already in place as well as a splitter to charge the second battery. Is it possible to add a battery bank to the extra battery on the vehicle, as well as another distribution panel to power the extra equipment that I plan on running? Thanks!