Check the Labeling
The first and easiest way is to simply read the labeling and description printed directly on the extension cord or its packaging. Reputable manufacturers will clearly state whether the cord is designed for indoor, outdoor, or both usages.
Key phrases to look for include:
- Outdoor
- Outdoor rated
- For outdoor use
- All-weather
- Water resistant
If the packaging does not specify outdoor use, assume the cord is for indoor use only.
Look for ‘W’ on the Jacket
Check the actual jacket or covering of the extension cord. Outdoor extension cords will have a ‘W’ printed on the outer jacket. The ‘W’ indicates that the jacket is rated for outdoor use and is water resistant.
Cords without the ‘W’ are typically not designed to withstand outdoor elements and should only be used indoors.
Inspect the Plug Ends
Examine both plug ends of the cord closely. Outdoor extension cords will have plugs that are sealed with a waterproof rubber or plastic coating.
This waterproof coating is easy to identify visually and provides protection against moisture when plugging and unplugging the cord. Standard indoor plugs lack this extra waterproofing.
Check the Wire Gauge
Outdoor extension cords need to have a thick enough wire gauge to handle being run longer distances outdoors.
Look for a wire gauge of 12 to 14 AWG (American wire gauge). These thicker wire gauges are less prone to overheating and voltage drops over longer runs.
Indoor cords are typically 16 to 18 AWG which is too thin for extended outdoor use.
Confirm It’s GFCI Protected
For safety, outdoor extension cords should be GFCI (ground fault circuit interrupter) protected.
GFCI protection shuts off power if it detects any abnormal current flow to prevent shocks. Outdoor receptacles must be GFCI protected, so any cords plugged into them should also have GFCI.
Verify the cord is GFCI protected by checking for a GFCI button or indicator light. Newer cords may also state ‘GFCI Protected’ on the jacket.
Consider Temperature Ratings
Cords designed for outdoor use in all seasons may additionally specify a cold weather temperature rating on the jacket or packaging.
Look for cords rated down to at least -20°F as they are designed to remain flexible and not crack in frigid temperatures.
Avoid Using Indoor-Only Cords Outdoors
Regular indoor extension cords lack waterproofing protections that can lead to fires or shocks when exposed to moisture or wet ground. The thinner wire gauge of indoor cords also presents overheating and voltage drop risks over longer outdoor runs.
Only use extension cords designed and properly rated for outdoor use when working outside. Replace any damaged or worn cords.
Outdoor Extension Cord Safety Tips
When using outdoor extension cords, follow these additional safety precautions:
- Use the shortest cord length necessary and avoid running cords through standing water or burying them.
- Check that all connections are tight and secure from moisture.
- Unplug cords when not in use and store indoors when possible.
- Don’t overload cords and use proper gauge for the power draw.
- Inspect cords frequently for damage and replace if needed.
- Consider upgrading to more durable cords made for commercial outdoor use.
- Use GFCI protected receptacles and look for cords with GFCI built into the plug.
Following cord ratings and taking basic safety measures helps prevent issues when using extension cords outside. Check that any cord is clearly intended and properly rated for outdoor use before plugging it in.
Frequently Asked Questions
How can you tell at a glance if an extension cord is rated for outdoor use?
Look for the ‘W’ printed on the jacket of the cord, which indicates a waterproof and weather-resistant rating for outdoor use. Outdoor cords will also have sealed, waterproof ends on the plugs.
What is the minimum wire gauge for an extension cord used outdoors?
12 to 14 AWG is recommended for outdoor extension cords. This thicker wire gauge can safely handle the extended distances and power loads of outdoor use better than thinner 16 or 18 AWG cords.
Can you use a 3-prong extension cord outdoors?
Yes, 3-prong grounded extension cords can be used outdoors if they are properly rated and labeled for outdoor use. The third prong provides important grounding as an extra safety protection. Make sure any 3-prong cords used outside are GFCI protected as well.
How do you waterproof an extension cord for outdoor use?
You cannot easily waterproof a standard indoor extension cord for safe outdoor use. Outdoor cords are manufactured using waterproof materials on the jacket and sealed connections. For outdoor use, it is highly recommended to replace any indoor cords with extension cords designed and UL-rated for outdoor use.
Can you run an extension cord through the rain?
It is not recommended. Outdoor rated extension cords are water-resistant but not intended for permanently wet conditions or submersion in water. Avoid running cords through standing water or leaving connections exposed to heavy rain if possible. Check connections for moisture if exposed to wet conditions.
Conclusion
Checking labeling, the jacket markings, plugs, wire gauge, and GFCI protection are key ways to verify an extension cord is properly rated for outdoor use before plugging it in outside. Proper rating helps ensure safety and performance. Any evidence the cord is for indoor use only means it should be avoided for outdoor applications to prevent potential electrical hazards or damage. Following the manufacturer ratings and outdoor safety tips allows you to use outdoor extension cords confidently.