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What Gauge Extension Cord Do I Need For An RV?

Written by Philip Lopez / Fact checked by Paul Lemaire

what gauge extension cord do i need for an rv

You need an extension cord to your RV because it runs on a power that’s similar to the power you obtain from your home’s outlets. Now the question is, what gauge extension cord do I need for an RV? That depends on how much amp power your RV uses.

If your RV needs to get 15 amps of power, use a 14-gauge extension cord. A 12-gauge extension cord is ideal for 20 amps, while 10-gauge is perfect for 30 amps. The 8-gauge and 6-gauge cords are suitable for 40 amps and 50 amps, respectively.

Let’s discuss gauge extension cords in more detail below.

Table of Contents

What Is Wire Gauge Thickness


Wire gauge thickness is one of the factors in determining an extension cord’s compatibility to your appliances and devices. It affects the wire’s current and heating capacity. Meanwhile, the extension cord length determines the cord’s load and power output capacity.

Extension cords have this American wire gauge (AWG) rating to measure electrical wire. Generally, the higher the AWG number, the thinner and lower capacity the cord.

Wire Gauge Wire Size For 15 Amp And 20 Amp RVs

Not all extension cords are made the same because it all boils down to the amperage required, the amount of voltage drop you can take, and the temperature rise permitted.

So, let’s begin with the 15-amp and 20-amp circuits. They operate on a power that’s almost the same as the power you use for household appliances, like stereos and TVs.

For camper vans that need to use 15 amp power, I recommend securing a 14-gauge extension cord that’s 0-50 feet long. You can also run a 12-gauge wire on a 15-amp circuit up to 70 feet. If you want to use a 10-gauge wire, make sure it runs up to 115 feet and nothing more than that to prevent voltage drop.

A 20-amp power needs a 12-gauge extension cord that runs up to 50 feet. You can also use a 10-gauge wire to run up to 85 feet on a 20 amp RV.

The 30-Amp Circuit: The Most Common RV Power

Thirty amps are probably the most common RV size and power in the RV world. Extension cords for this power are scaled for 30 Amps at 125 volts.

You’ll have no issues running a 10-gauge extension cord on a 30-amp circuit because it will have less voltage drop. You can run the 10-gauge wire as far as 150 feet. Ten-gauge extension cords are known to be strong and durable enough to endure heavy-duty use outdoors, making them perfect for safely powering your tools.

With a few precautions, you can actually use an 8-gauge wire to your 30-amp circuit. Make sure that your circuit breaker and device connections accept the 8-gauge wire. Many devices meant for 30-amp connections also accept 8-gauge wires at their contacts besides the #10 cable.

You don’t want to hook a cheaper 14-gauge extension cord in your 30-amp rig with a series of dog-bone adapters because you’ll increase the voltage drop and the risk of overheating.

40 And 50 Amps: The Big Boys

The 40 and 50-amp circuits are the big boys in the camping world because they can supply 240 volts of power to big appliances, like an electric range. They’re typically found at campgrounds, together with the 30-amp electrical systems.

For a 40-amp RV, you’ll need an 8-gauge extension cord, which is thicker than its 10-gauge counterparts. A 6-gauge is compatible with a 50-amp circuit and breaker, even up to 55.

Deciding The Right Length Of Extension Cords

Besides the gauge wire thickness, you’ll need to consider the extension cord length when choosing the right extension cord. The length affects the extension cord’s capacity to power the RV.

In general, power travels farther as the extension cord gets longer. A greater length reduces the total amps entering the machine, hence straining both the machine and the outlet. For efficiency, look for the shortest extension cord to reach the machine quickly.

The extension cord shouldn’t be as long as the power cord either. As you know, extension cords have more resistance when they get longer, hence less power to reach your device. When your device is starved with power, it can decrease its lifespan as it works double-time to draw electricity.

According to Electrical Safety Foundation International (ESFI), a 25-50 feet extension cord is ideal for 1-13 amps (16 gauge), 14-15 amps (14 gauge), 16-120 amps (12-10 gauge). A 20-amp RV can run a 10-gauge extension cord up to 100 feet, while a 15-amp RV can run a 10-gauge extension cord up to 150 feet.

Extension Cord Storage And Safety Tips


Extension cords offer power for appliances and equipment with cables that are far away from the electrical outlet. To avoid fire hazards and electrical shocks, here are some safety tips you can follow.

  • Store Properly

To properly wrap an extension cord, hold it in one hand and extend the cord up to arm’s length. Next, bring the wire back around to the holding hand to make large loops and reduce cord damage. Wrap something around the extension cord to hang it safely.

  • Never Overload Your Extension Cord

Each extension cord contains a maximum amperage rating or an electrical current limit for safety. Check the appliance you want to connect and select an extension cord with a higher amp rating than your appliance. If you like to link multiple equipment, add all the amp requirements to prevent an overload.

If the extension cord doesn’t provide an amp rating, determine its wire gauge to compute its current capacity. The higher the gauge, the lower the wire’s capacity. A 10-12 gauge extension cord is excellent for heavy-duty equipment, like air compressors and chainsaws. A 14-gauge cord is perfect for medium-duty applications, like power drills. A 16-gauge cord is ideal for light-duty appliances, like portable fans and Christmas lights.

  • Use The Right Prongs

Extension cords either have two or three prongs. If your plug has two slots, don’t use three-prong plugs. Never remove the ground pin to lift it forcefully because it can cause electrical shock.

A three-prong cord seems to be better than the two-prong model because it consists of a particular section for the ground wire. If you have to buy a new extension cord, upgrade your RV with a three-prong version for improved electrical safety.


Now that I’ve answered your question – what gauge extension cord do I need for an RV, you know what to choose next time.

Use a 14-gauge extension cord for 15 amps, 12 gauge-gauge for 20 amps, 10-gauge for 30 amps, 8-gauge for 40 amps, and 6-gauge for 50 amps. Don’t forget to consider the cord length because it affects the load and output capacity.

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Read more: Tips to make a 30 amp generator extension cord.

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