Everything You Need to Know About Wires for Your Van

Here’s a little more information about selecting wires and wiring that will be helpful to you as you proceed through the steps in The Power You’re Supplying: It’s Electrifying.

DISCLAIMER: We are not qualified or electricians. Do not rely on our advice regarding electrical systems and installations. Do your own education, research, or hiring of qualified electricians to electrify your van. The following is intended to describe what we did; not what you should do, although it may help you understand some of the jargon and commonly used components.

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How to Decide What Wire Gauge to Use

Use a calculator (like the Wire Barn Wire Size Calculator) to figure out what gauge wires are required (different amps over different lengths require different size wire to carry the electrical load safely).

For example, we estimated we would need a 1 foot wire from the 12V disconnect to the ground point and it had to handle 150A. Plugging those values into the calculator with a 5% drop shows that a short length like this can use anything from 0 to 14 gauge wire. However, the 21 foot wire from our vehicle battery to our house battery can only use a 0 to 2 gauge wire. We ran the calculation for every single wire, which gave us a whole range of wire sizes. Then we “rounded down” (the lower the gauge number, the thicker the wire, and the higher amps it can handle) to the nearest of 3 common wire sizes to consolidate them:

We used 2 gauge wire from the batteries to the battery isolator, disconnect, fuse, and shunt (150A).
We used 6 gauge wire from the battery to the circuit breaker, low voltage disconnect, and inverter, and fuse block (100A).
We used 14 gauge wire from the fuse block to all of the 12V equipment we use in the van (fan, lights, dimmer, USB outlets, and fridge) (0.5-10A).

How to Trim Wires to Length

This is a pretty standard procedure for trimming wires to length.

Shopping List

Wire Strippers: Cuts, strips, and crimps wires from 10-22 gauge wire

Bolt Cutters: Cuts wires from 0-8 gauge

Crimping Tool: Extra mechanical help to make the crimps on the very thick 2AWG wires.

Utility Knife: Cuts wire insulation from 0-8 gauge wire

Pliers: Cuts wire insulation from 0-8 gauge wire

Electrical Tape: Keeps terminals attached securely (since your van is not a static environment) to prevent electrical shorts and fires

Step-by-Step Procedure

Cut the Wire to Length

Use the cutter on the wire strippers or a bolt cutter, for larger wires.

Strip the Insulation

Strip about 3/4” of insulation from the end of the wire with wire strippers or (carefully) with a utility knife.

Put a Terminal on the End

Twist the now bare metal wire ends and push the bare metal wire ends into a terminal. (Be consistent. For 14 gauge wire, we typically used bullet terminals, using the male end on the device-side wires and the female end on the wire on the battery-side wires.)

Crimp the Terminal onto the Wire

Crimp the terminal onto the wire with a crimping tool (for thick 2 gauge and 6 gauge wire), or pliers or the crimping tool on our wire strippers (for thinner wires).

Check the Terminal

Tug to make sure it is on tight.

Tape It Up

Wrap the joint with electrical tape, if needed.