Difference between indoor and outdoor extension cords?

Indoor and outdoor extension cords have separate uses and should never be used interchangeably.

Using the right cords meant for outdoors and indoors is critical for safety.

So, how can you tell the difference between indoor and outdoor extension cords?


Indoor cords lack the protective insulation that outdoor extension cords have.

Outdoor cords are designed to withstand moisture, sun damage, and temperature changes.

Cords for indoor use are not designed to endure the elements.


Indoor appliances generally require less amperage while outdoor devices often require more.

Thus, outdoor extension cords typically have a higher amperage rating than indoor extension cords.

Physical Features

On the packaging of a new outdoor cord or on the cord itself, check for the letter ‘W’.

This letter designates that the extension cord is safe for use outdoors.

Many indoor-use extension cords only have two prongs. While all outdoor extension cords will have three prongs.

Outdoor extension cords are often brightly colored in orange rubber, plastic, or vinyl.

This is intentional so as to increase visibility and avoid tripping or mowing over.

Extension Cord Safety

When your cords are not in use, safely store them off the ground either rolled or coiled up as they were when first purchased.

Hang them in a high, dry space protected from sunlight and away from water.

Both indoor and outdoor extensions cords are meant as a temporary supply of power. They are not a permanent solution. Substituting permanent wiring with extensions cords can be extremely dangerous.

If you’re shopping for new cords, purchase only the ones with inspection labels from UL, CSA, or another accredited source. These certifications verify quality and safety.

If you don’t already have ground fault circuit interrupters (GFCIs) protecting the outlets around the exterior of your home, consider purchasing a GFCI extension or adapter to make outdoor use of extension cords more safe.

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