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How to Run Extension Cord From Inside to Outside? (4 Steps)

Written by Edwin Jones / Fact checked by Andrew Wright

how to run extension cord from inside to outside

Do you need to use an electrical device outside, but your outdoor outlet is full? Perhaps, you’ve thought of using an extension cord that starts inside your home and reaches outside.

It’s a great idea, but how are you supposed to do it while keeping your house closed?

Worry not! I made this article to show you how to run extension cord from inside to outside without leaving your residence unsecured.

Ways to Run Extension Cord From Inside to Outside

Running extension cord outside might be the best way to use appliances outdoors. However, to prevent intruders from entering your property, you need to secure all of its openings.

At the same time, you should have heavy-duty electric extension cords for outdoors that connect to a GFCI outlet for additional safety.

With that in mind, here are some methods you can use to run power outside your house.

1. Run Extension Cord Through Door


Once you’ve found an indoor outlet for your cable, you can run the wire through the door to the outside of your home. This way, there’ll be no need for an outlet on the external walls of your residence.

However, you might need to purchase an ultra thin flat extension cord outdoor model. Otherwise, regular extension cables might be too big to go under the door.

2. Run Extension Cord Through the Window


Running an extension cord through the window might be the best way to power your device outside. Using the proper tools, you can ensure better insulation, meaning no unwanted draft or heat will come into your house.

What’s exciting about this technique is that you do not need to spend too much on buying expensive tools. If you are interested in trying it, here are the tools and guide.

What to Prepare

  • Large diameter pool noodle
  • Marker
  • Cutting knife for cutting the pool noodle
  • Drill and drill bit for making a hole
  • Tape measure

Step 1. Measure the Window and Cut the Pool Noodle


  • To start the process, you first need to measure the width of your window’s opening from both sides of its frames.
  • Then, measure the same distance on your pool noodle and mark it.
  • Using the mark you’ve made, cut your pool noodle

Step 2. Make a Hole and Slit

  • Now, determine the thickness of your extension cord and drill a hole on your pool noodle; the hole should fit the cord snugly.


  • Next, you can create a slit on the side of the pool noodle up to the hole you drilled. This slit will allow your extension cord to get into the hole you made.


Step 3. Create more slits on the pool noodle

  • Measure the insides of your window frame (the track where it slides up and down) and note down the number.


  • Then, make a horizontal slit on both ends of the noodle with the same measurement you got. The cut should be perpendicular with the hole in the previous step.


Step 4. Install it to the Window

  • After making your pool noodle ready, you can install it in your window.

Insert the cord into the hole of your pool noodle. The slits on the noodle should fit the tracks of the window slide frame.


  • At this point, you can close the window.


  • The same trick above can be used when running an extension cord from generator into the house. It is helpful, especially when you haven’t installed a wall socket connected to a transfer switch.
  • You can use a device called a security window alarm. It will make noise when the window is moved, alerting you to thieves who want to steal your belongings.
  • You should not bury an extension cord as it should be for temporary use only. It may be a hazard if you run an extension cord underground or through a wall as you won’t know what is happening to the cable.



How Do You Run an Extension Cord Through a Window?

It is easy to run an extension cord through the window. All you need to do is to use a flat extension cord, or you can use the second DIY method above.

How Do You Run a Power Cord from an Outside Wall?

When installing a power cord on outside walls, you must have a conduit and install it above the ground. This tool can protect the cord from harsh elements outside, such as direct heat from sunlight and animal bites.

Why Should You Not Use an Indoor Extension Cord in Your Backyard?

Using an indoor extension cord outside is not a good idea. Here are some reasons why.

  • Indoor extension cords often have thinner insulation than outdoor-rated ones. As a result, they may be unable to withstand extreme temperatures outside.
  • An indoor cable often has a thinner wire diameter than an outside cord, which means it can only handle a limited amount of electricity.
  • It also has a shorter length, which is insufficient for operation outside.
  • You run the risk of fire when using an indoor extension cord for outdoor use. Since it often doesn’t have a grounding function, it is easily damaged when exposed to water.


Using the guide and tools above, you will know how to run extension cord from inside to outside without causing damage to your house. This idea is useful when your external outlet is full, or somehow it is not working.

That said, an extension cord is not for permanent application, so the tricks I shared should be reserved for temporary or emergency situations only.

If you frequently run an extension cord outside your house, you should consider putting an additional circuit outdoors. Calling a professional for advice and assistance is also an excellent option.

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