Choosing the right cables for your inverter can be downright confusing.
You think it’s going to be a simple task to buy inverter cables, but you can quickly get confused about finding the correct size.
You’re not the only one out there searching things like ‘What size wire for a 400 watt inverter?’
We’ve all done it!
It’s still not always easy to find a clear answer though.
That’s why I wrote this guide to help you find the right size wire for any sized inverter.
Together we’ll go through the considerations in simple English, take a look at an inverter wire size chart, and give you exact sizes for common inverter sizes.
Why Wire Size is Important
Let’s start with a quick look at why using the correct wire size is so important.
The size of the wire mainly takes into account the amount of amperage or ‘amps’ flowing through an electrical circuit.
If the wire size, known as gauge, is too small it won’t be able to cope with the energy flowing through it. This becomes dangerous! It can trip the fuse and even melt the cables causing a fire.
So why not always use the biggest wire? Well, if you use a wire that’s too big the voltage in your circuit will drop. This is the force of electricity – a bit like water in a hose. To add another problem, if you use a cable that’s too long voltage will also drop so you need to adjust your gauge again for this!
Don’t worry, we’ll factor all of this into our wire size guide below.
Inverter Wire Size Chart
Now you have a fundamental understanding of wire sizes and factors to consider, we can look at this table of inverter and wire sizes. You should always aim to keep wires less than 10 feet. If you go any longer then you will need to use a bigger gauge wire to account for resistance that lowers voltage.
|Inverter Size||Wire Gauge Less than 10 ft|
*The larger the AWG rating the thinner the cable. Use this calculator to find your own wire sizes.
How to Work Out Wire Size for Inverter
The easiest way to work out what wire size is to use the table above. You can start to do calculations but you can also work off some general rules of thumb.
- 8 AWG wires are used for 500 watts or below
- 4 AWG between 500 – 1000 watts
- 2 AWG between 1000 – 2000 watts
- 0 AWG between 2000 – 3500 watts
- 3/0 AWG between 3500 – 5000 watts
- 4/0 AWG over 5000 watts
If you want to accurately work out what size wire you require, you need to know the maximum amount of amps that will flow through your circuit. To work out amps you use the formula – watts ÷ volts = amps.
For example, if you’re using a 2000 watt inverter with 12V input it would be 2000W ÷ 12V = 166.6 amps.
So you need a wire that can handle more than 166 amps.
Now let’s find the wire size using amps on this table below using this inverter wire size calculator:
Using the calculator above, let’s find a wire size for all the common 12V inverter wattages.
What Size Wire for a 100 Watt Inverter?
For a 100 watt inverter a 16 AWG wire is suitable for 10ft or under.
This is because you will draw a maximum of 100 watts at 12 volts which results in 8.3 amps in the wire.
What Size Wire for a 200 Watt Inverter?
With a 200 watt inverter you can use a 14 AWG wire for 10ft or less.
This is because a 200 watt 12 volt inverter will draw a maximum of 16.6 amps.
What Size Wire for a 300 Watt Inverter?
For a 300 watt inverter a 12 AWG wire is good for 10ft or under.
This is because you will pull a maximum of 300 watts at 12 volts which results in 25 amps in the wire.
What Size Wire for a 400 Watt Inverter?
For a 400 watt inverter a 10 AWG wire will work for 10ft or under.
This is because you will pull a maximum of 400 watts at 12 volts which results in 33.33 amps in the wire.
What Size Wire for a 500 Watt Inverter?
With a 500 watt inverter an 8 AWG wire will work for 10ft or under length.
This is because you will use a maximum of 500 watts at 12 volts which results in 41.66 amps in the wire.
What Size Wire for a 750 Watt Inverter?
Using a 750 watt power inverter you can use a 6 AWG cable for 10ft or less.
This is due to the fact that you will be drawing a maximum of 750 watts at 12 volts which results in 62.5 amps.
What Size Wire for a 1000 Watt Inverter?
For a 1000 watt inverter a 4 AWG wire would work well if it’s under 10ft.
You would use around 83.3 amps when drawing 750 watts at 12 volts.
What Size Wire for a 2000 Watt Inverter?
A 2000 watt inverter will draw around 208 amps with a 12 volt input. This would require a 2 AWG wire at 10ft or less in length.
What Size Wire for a 3000 Watt Inverter?
For a 3000 watt inverter it is common to use a 0 AWG wire size. This is because at max load of 3000 watts at 12 volts would draw 250 amps.
What Size Wire for a 4000 Watt Inverter?
With a 4000 watt power inverter you can use a 3/0 AWG wire when it’s 10ft or less.
If you draw a max load of 4000 watts at 12 volts it would pull 333 amps.
American Wire Gauge (AWG) is the standard US unit of diameter for a conductor. It is used to size things like inverter cables as they use copper for their wire.
The higher the AWG number the thinner the wire. Some people like to convert the diameter of a wire into millimeters to help them understand the size. Let me give you an example, an 8 AWG wire is 3.26mm in diameter. And a 1 AWG wire is 7.35mm in diameter. So a 1 AWG is more than double the thickness of an 8 AWG wire. You can read more in-depth about American Wire Gauge here.
How Long Can Inverter Cables Be?
Less than 10 feet.
It is best to use the shortest and thickest cable you can. That means it is always better to mount your inverter as close to the battery as possible to keep your cables short.
You should try to keep your inverter less than 10ft (3m) in length to retain the correct voltage and amperage.
This is because the shorter the cable the less resistance there is for the voltage. As cables get longer voltage drops due to resistance in a wire. Using a longer cable means you will have to reduce its thickness (higher AWG) in order to increase voltage.
Can I Use Jumper Cables for an Inverter?
You should not use your car jumper cables to run your inverter. This is because an inverter needs specific sized wires to work properly. Using car jumpers will run the risk of tripping a fuse, melting the cables, and even starting a fire. Or they could be too thick meaning you won’t get the correct voltage to your inverter.
Jumper cables can vary between 1 and 10 AWG so it is likely they are not suitable for your inverter!
Should Inverter Cables be the Same Length?
Yes, you should ensure your inverter cables are all the same length. This will help to maintain a constant voltage around the circuit. Voltage can change depending on the length of a wire. The longer a wire the more resistance and low the voltage becomes. A couple of millimeters isn’t important. But you might have problems if you have a 2 foot positive wire and a 10 foot negative wire!
How Far Can Your Inverter Be from Batteries?
You should try to keep your inverter as close to your batteries as possible. It is best to keep it within 10 feet, or even closer is better. This is because you want the wires as shorts as possible to maintain voltage for your wire size.
Final Words on What Size Wire For an Inverter
I hope this article has helped you pick a wire size for your inverter. My best advice is to check the user manual or technical information for the ideal wire size. Plus you can contact the manufacturer. Most inverters come with the correct wire size and if you keep the cables less than 10ft you should have no problems.
There are many different factors that come into play for deciding wire size. To be honest for short cables you can use the rule of thumb listed in the table above. Or use this handy calculator to get a bespoke reading for your setup.
Thanks for reading.
Hi, I’m Michael, the editor here at Watt A Lot.
After years of experience with off-grid power like solar panels, inverters, and batteries I decided I should share my hands-on knowledge with you. In my professional and personal life, I’ve needed to find electrical solutions for remote situations from owning a food truck, to running events at the top of mountains, to my converted campervan. So whether you’re looking for the best products or fixing an electrical problem, you can rest assured my advice comes from real hands-on experience.