5 Key Differences Between Outdoor and Indoor Extension Cords

Outdoor cords have thicker, weather-resistant insulation. Indoor cords lack this and will crack or fail when exposed to moisture, UV light, or temperature swings.

Look for a “W” or “WA” marking on the cord jacket. This indicates it is rated for outdoor use. If the marking is absent, the cord is for indoor use only.

Outdoor cords are built to handle rain, snow, and direct sunlight. Indoor cords are not designed for these conditions and pose a safety risk if used outside.

The gauge (thickness) of outdoor cords is often heavier to handle longer runs and higher power demands. Indoor cords may use lighter gauges for shorter distances.

Using an indoor cord outdoors voids its safety certifications and can lead to electrical shock or fire. Always match the cord to the environment.