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How to Make a 30 Amp Generator Extension Cord: 4 Steps

Written by Philip Lopez / Fact checked by Paul Lemaire

how to make a 30 amp generator extension cord

It’s important that you know how to make a 30 amp generator extension cord because it will allow you to run your lights, TV, and other devices during a power outage. It’s impossible to hook all your electronics directly into the generator outlet, so you need an extension.

It’s easy to make a DIY extension cord because all you need is a few electrical parts, such as male and female plugs, a service cord, and a screwdriver. Simply, wire the cord ends to the plug, and you’re done!

To get you started, here are the items to prepare and the instructions.

Table of Contents

What to Prepare


  • Male twist lock plug
  • Female twist lock plug
  • 10/4 portable service cord, 10 feet or according to preference
  • Screwdriver
  • Razor knife
  • Wire stripper

Step-By-Step Instructions

Now that you have gathered the tools, it’s time to make a 240 volt 30 amp generator extension cord.

Step 1: Prepare The Female Plug and Cable


To make a 30 amp cable, let’s start with the female plug. This plug is a 2 or 3 prong receptacle that allows your RV appliances to hook in for operation when using the generator.

  • Use a screwdriver to loosen the screws that hold the plug cover and remove it.
  • Take out the little spacers on the base and insert the cable in the middle.
  • Hold the top end of the cable and cut about two inches of the insulation with a razor knife to reveal the wires.
  • Remove the paper for each conductor, then strip 0.5 inch off each wire end. You don’t want to strip the conductor too short or long because it might cause a bad circuit connection.

Step 2: Wire The Female Plug


On the bare female plug, you’ll see markings to help with the 30 amp generator plug wiring process. The letter G indicates the color green, while the W is for the white or neutral wire. The X and Y markings are for hot conductors.

  • Twist each wire to ensure that everything fits into the terminal.
  • Insert each wire into its designated terminal. Remember the markings.
  • Tighten the screws with a screwdriver to make the connection secure.

Step 3: Secure The Female Plug

Now that all the wires are tightened to their place, it’s time to put all the pieces together. Remember the base or the retainer that you slide down onto the cable? We’ll bring that back into its position.

  • Slide the base back up to the plug. Find that notch and press it in place.
  • Tighten all the screws to keep the plug together.
  • Give a little tug to test the tightness of the connection. If it’s a little loose, retighten the screws.

Step 4: Connect The Male Plug


Once the female plug is done, it’s time to connect the male end of the 30 amp RV extension cord. It’s basically the same process as the female plug.

  • Loosen the screws to disassemble the male plug.
  • Remove the spacers and slide the retainer onto the other end of the cable.
  • Cut and remove the insulation, revealing the wires.
  • Insert the wires into the terminals where they belong.
  • Tighten the screws and put the plug components back together.

Tips for Choosing And Using Extension Cords

  • Pick a slightly longer cord to avoid the need of using multiple extension cords, which can affect power and safety.
  • Use a thicker cord if you’re looking for more power. Keep in mind that a higher AWG number doesn’t mean a thicker cord. When wiring a 30 amp generator plug, use at least 10 AWG.
  • Make sure that the cord has weatherproof insulation for protection from moisture and other harsh elements outside. It should remain flexible even when used in winter.
  • Never ignore a ground prong because it helps protect the appliances from electrical damage.
  • While in use, never bend or crush the cable as it may cause an electric shock.



What are the ways to determine the capacity of an extension cord?

The thickness and length of the cord are great determinants of capacity. A thicker generator power cable means more capacity to carry power. The cord’s thickness is expressed in AWG.

The lower the AWG number, the higher the electrical rating. Between 10 and 12, the former has a higher capacity.

The cord’s length is inversely proportional to its load. The longer the cord, the lower its capacity due to high resistance.

How long can a 30 amp generator extension cord be?

You can easily find a 10 or 30 feet generator extension cord. If you want to use a portable generator extension cord for recreation, you can use a short cord to supply more power.

For emergency backup, a generator cord to house setup needs about 20 feet or more to keep the gas emissions out.

You can go as far as 50 ft or even more as long as you use a thicker wire gauge. More specifically, you can run the length of a 4 prong 30 amp generator extension cord up to 65 feet if you have a 10 gauge wire.

How many watts can a 30-amp generator cord handle?

Remember the wattage formula, which is volts multiplied by amps. If you run a 30 amp extension cord on 120 volts, expect a maximum wattage of 3,600. Using 240 volts generates a higher wattage capacity of 7,200.

Can I use a 50 amp generator cord on a 30 amp generator?

Yes, you can use a 50 amp cord on a 30 amp generator as long as your unit offers a 50 amp outlet. If your generator only has a 30 amp outlet, you’ll need to use a generator extension cord 30 amp model.

Also read: What size generator for a 30 amp RV


I hope that you know how to make a 30 amp generator extension cord at this point. It’s easy if you know the right gauge and length of the wire. Remember, it’s better to go thicker and longer than to be thin and short.

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