How to Wire Inverter to RV Breaker Box? Proper Guideline

Connecting an inverter to an RV electrical system can seem intimidating for some RV owners. However, with the right materials and safety precautions, it is a straightforward DIY project.

In this comprehensive guide, together I will walk through the complete step-by-step process of wiring an inverter to an RV breaker box. Moreover, you will be able to explore tips and recommendations to make the installation process smooth and hazard-free.

So let’s get started!

How to Wire Inverter to RV Breaker Box

Steps for Wiring Inverter to RV Breaker Box 

Before beginning the project, you need to gather all the required materials and tools. Having everything in place ahead of time will make the installation process faster and simpler.

Here is a checklist of items you will need:

Inverter, Get a pure sine wave or modified sine wave inverter depending on your RV’s electrical system and devices you want to run. Choose an inverter wattage based on the wattage of devices you want to power. Also, consider getting an inverter with smart features like low battery shutdown.

Wires, For wiring the inverter to the battery bank and breaker box, you will need 6 AWG or 4 AWG wires depending on your inverter wattage. These thick wires efficiently handle high amp loads.

Inline fuse, An inline fuse connected close to the battery protects against short circuits and overloads.

Breakers, Install breakers between the inverter and RV breaker box for overcurrent protection.

Battery bank, Make sure your RV battery bank has enough capacity to handle the power requirements of the inverter.

DC disconnect switch, It isolates the batteries for safe servicing.

Copper lugs, For securely terminating thick battery cables to the inverter DC terminals.

Wire stripper, For stripping the insulation of the wires to expose the copper strands.


Multimeter, For measuring voltage and troubleshooting if necessary

So with the right supplies in hand, you are all set to get started!

The process involves securely mounting the inverter, connecting it to the battery bank, wiring the AC output to the RV electrical panel, and testing the setup.

Here are the detailed steps to follow:

Step 1 – Place the Inverter in a Well Ventilated Place and Near the Battery Bank

Begin by selecting a proper location to install the inverter. It is ideal to place it close to the RV house batteries in a ventilated, protected area away from direct exposure to rain or sun.

Make sure to follow the minimum clearance space recommendations specified by the inverter manufacturer. Proper air circulation prevents the unit from overheating.

Also, having the inverter nearer to the 12V battery bank reduces cable length so voltage drop and power loss can be minimized.

Tip: Installing the inverter in an existing compartment, like the basement storage area is convenient. Otherwise, you can build a dedicated ventilated box for it.

Step 2 – Install the Inline Fuse with the Inverter

Connect an inline fuse holder with the appropriate amp-rated fuse on the positive battery cable line to the inverter DC input terminal.

Having a fuse box allows you to service blown fuses easily without accessing the inverter. Size the fuse about 125 to 175% of the inverter’s rated current.

Mount the fuse box right next to the battery bank to protect the cables running from it to the inverter. In case of a major vehicle electrical failure, it blows the fuse rather than damaging circuits.

Step 3 – Connect the Inverter to the Battery Bank

Run heavy gauge battery cables from the RV house batteries to the inverter unit and connect it. 6 AWG or 4 AWG wires work well depending on the wattage.

While connecting, ensure:

  • Cables are sized correctly based on the inverter draw. Undersized cables lead to power loss.
  • Use copper lugs for terminating wire ends and provide a solid connection to the DC terminals.
  • Connect the red wire lead to the positive terminal and the black to the negative.
  • Tighten the connections properly but do not over-tighten to prevent terminal damage.
  • Double-check polarity before turning on the inverter.

Step 4 – Connect the Inverter to the RV Breaker

Run wires from the AC output terminal of the inverter to the AC input of the RV distribution center or breaker box.

The output voltage of most inverters matches the 120V AC required to power RV appliances and outlets.

Steps to follow while connecting to the breaker box:

Step 1, Shut off the main circuit breaker of the electrical panel before wiring.

Install separate breakers between the inverter output and RV box for overcurrent protection.

Step 2, Identify the terminal for Hotline 1, Hotline 2, and Neutral line inputs and connect respective wires.

Step 3, Properly label the additional breakers controlling the inverter connection.

Tip: Running the inverter output via a transfer switch or an interlock kit instead allows you to power loads from the shoreline or generator as well when available.

Step 5 – Set Up the Battery Power System

You need ample battery power to supply steady DC input to the inverter while running appliances.

To set up your battery bank:

Step 1, Use good quality deep cycle lead acid or lithium batteries designed for RV application.

Step 2, Determine the total battery bank capacity needed based on the power requirements of the inverter loads.

Step 3, Install a volt meter to monitor the battery bank voltage easily.

Consider a solar panel setup to charge batteries and prevent draining while dry camping.

Step 6 – Load Up the Inverter and Check

The final step is to test and confirm the proper working of the installed inverter.

Step 1, Before powering up the system, check all connections to ensure correct wiring between the battery, inverter, and breaker box.

Step 2, Close the main breaker first and then turn on the inverter.

Step 3, Gradually add appliances and devices to load the inverter.

Step 4, Monitor performance – Check the output voltage, no tripped breakers, no overheating, etc.

Step 5, Run the loads for some time to validate stable uninterrupted power delivery from the inverter.

Congratulations! You now have a fully functional inverter installed in the RV electrical system.

Bonus Step – Go for a 2 or 3-Way Changeover Switch for Connecting Instead of Direct Connection

Instead of directly wiring the inverter to the RV breaker box, you can add a 2 or 3-way changeover switch in between.

It allows conveniently switching the power source for the RV appliances between shoreline or generator vs inverter battery without any rewiring.

So during dry camping rely on the inverter and while plugged into a campsite, simply flip the changeover switch to receive shoreline power.

Installing this flexible switching option costs slightly more upfront but adds great value to everyday usability.

Things You Will Need to be Careful about While Wiring Inverter to the RV Breaker

While an experienced DIYer can safely install an inverter in about 2 hours, rushing through the job or ignoring safety measures can lead to hazards and damage.

Here are some important precautions to take:

Turn Off the Battery Disconnect Switch Before Making Any Connections

Working on powered electrical systems can lead to nasty shocks or short circuits. So always turn off the battery disconnect switch before starting the inverter cabling work.

Use the Correct Size Wire

Undersized cables lead to voltage drop across long cable runs resulting in power waste and reduced efficiency.

Refer to the inverter manual for recommended battery cable and ampacity based on wattage.

Strip the Ends of The Wires Properly

Improper wire stripping or frayed strands can cause loose faulty connections.

Use the right size wire stripper. Strip just enough insulation without nicking the inner core.

Connect the Wires to The Correct Terminals.

Mixing up wires leads to reverse polarity that can destroy the inverter upon power up.

Always double-check check you have connected positive to positive and negative to negative terminals before switching on.

Tighten the Connections Securely

Loose electrical connections can draw arcing leading to terminal meltdown and fire hazards.

Tighten cables at the battery, inverter, and breaker box terminals securely using the torque wrench for good contact.

Double-check All of Your Connections Before Turning on the Power

It takes very little time to inspect all wiring but saves you from potentially damaging miss-wired connections.

So take a minute to trace all cables end-to-end before you re-energize the system.

By taking basic safety precautions, you can safely install an inverter to power your RV. Position it properly, size the cabling appropriately, ensure solid connections, and take due diligence while wiring.

Investing in a good quality inverter coupled with proper installation provides you with reliable off-grid power for all your RVing adventures!

Frequently Asked Questions with Answers

How do I size the inverter for my RV?

Size your inverter 25-30% more than the total wattage of devices you need to run simultaneously. Adding up appliance wattage and multiplying by 125% gives you the right inverter size. Also, factor in power surge needs.

What gauge wire should be used for the inverter?

For an inverter less than 5000 watts, use 6 AWG wires. For a high capacity 10000 watts inverter, upgrade to thicker 4 AWG wires. Refer inverter manual.

Can an inverter drain an RV battery?

Yes, running devices via an inverter draws current from the batteries. Frequently monitoring battery voltage and recharging ensures it does not drain completely.

Is it okay to connect the inverter directly to the battery?

While simpler, it overloads risks by bypassing fuses/breakers. The recommended method is to install a fuse box near the battery and connect the inverter via breakers too.

How far can an inverter be from the battery bank?

Within 5 feet is best to minimize voltage drop. Up to 10 feet is fine too by using thicker wires like 4 AWG to reduce power loss across longer distances.

End Notes

Installing an inverter to power AC appliances in an RV encourages off-grid camping adventures without foregoing modern conveniences.

This guide covers a step-by-step breakdown of materials needed, safety tips, and a wiring diagram to connect an aftermarket inverter to the existing RV electrical system.

While seemingly complex, taking due precautions and following technical recommendations at each stage makes the job quite manageable even for a first-timer.

So go ahead and set up your inverter safely. Let us know if you have any questions in the comments section below. And happy travels living off-the-grid!

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