How to Use Extension Cords Safely

Extension cords come in handy when you need to plug in electronics, appliances, instruments, or tools where outlets are hard to reach. However, improper extension cord use is also one of the leading causes of home electrical fires. In fact, according to the Electrical Safety Foundation International (ESFI), roughly 3,300 home fires are caused by extension cords each year.¹

Fortunately, you can still enjoy the convenience of extension cords without putting your home and safety at risk. In this guide, we explore the dos and don’ts of extension cord use to help you avoid overloads and fire hazards.

The Dos of Extension Cord Use

Extension cords are helpful tools, but only when properly rated, certified, and used correctly. Below are some tips for using extension cords safely:

Do Inspect the Cords for Damage

Any time you’re about to use an extension cord, take a moment to inspect it for cuts, frayed wire, or broken prongs. Never use a damaged cord with exposed live wire, which is a serious fire hazard.

Just a few seconds of extra precaution can make all the difference in reducing the likelihood of a devastating electrical fire.

Do Stay Within Wattage and Amperage Limits

When using an extension cord, always make sure the device you’re plugging in fits within the cord’s wattage and amperage rating. Never plug in anything that uses more power than the cord is rated for. Going over this limit can cause the cord to overheat, melt, or even start an electrical fire.

Do Check for Safety Certifications

Before purchasing or using an extension cord, it’s important to check that it has official safety certification from trusted independent testing labs, such as:

Extension cords with these certifications have been vigorously tested to the latest quality standards and are safe to use with proper care.

Do Follow Indoor-Outdoor Use Ratings

Every extension cord is rated for either indoor use, outdoor use, or both. You should always follow the product label and only use them in the environment they are rated for:

By using indoor and outdoor extension cords only where they are rated for, you can keep the cord in good condition and reduce the risk of electrical fires.

The Don’ts of Extension Cord Use

What you do with an extension cord is just as important as what you don’t. Below are some safety risks that you should always avoid when using extension cords:

Don’t Daisy Chain Extension Cords

Daisy chaining is linking multiple extension cords or power strips together end-to-end. Daisy chaining is incredibly dangerous because it can cause electrical overload, generate excessive heat, and significantly raise the risk of an electrical fire or shock. It’s strictly against fire codes set by the National Fire Protection Association (NFPA).

Over-relying on extension cords often signals that your current electrical setup isn’t meeting your needs. It’s always better to have an electrician install additional outlets instead of daisy-chaining so you can safely access power where you need it most.

Don’t Cover Extension Cords

You should never cover extension cords by running them under carpets or rugs, or through walls, doorways, ceilings, or floors. A covered cord can easily overheat and potentially start an electrical fire. Placing furniture over it can also damage the wire or its cover, creating additional safety risks.

The only exception is dedicated cable hiders designed specifically for extension cords, which help reduce tripping hazards. Otherwise, always ensure they are visible and have room to breathe.

Don’t Staple or Pinch Extension Cords

It’s important to never nail or staple extension cords to baseboards, or run them through doors or windows where they might get pinched. This can tear the insulation and expose the live wire inside, creating a serious fire hazard.

Instead, try these alternatives to safely manage and route extension cords:

Taking these precautions helps protect your extension cord from damage and reduces the risk of electrical hazards.

Don’t Use Extension Cords for Fans or Heaters

The Electrical Safety Foundation International (ESFI) advises against using an extension cord or power strip for fans or heaters.¹ These appliances are frequently moved between rooms and often have to be maneuvered around existing furniture, so it’s understandable why an extension cord would be tempting. However, they draw a lot of power and can cause dangerous electrical overload or overheating.

If you need to power a fan or heater, it’s best to plug it directly into a wall outlet. If you don’t have enough outlets to support your heating and cooling needs, it’s always safer to have more installed by an electrician than to use extension cords improperly.

Safer Homes Start with Expert Electricians

Your home’s electrical setup does so much more than power your daily life. It directly influences the safety of you, your belongings, your home, and anyone else residing within it.

At Schafer Electric, safety is always our number one priority. Our licensed electricians help homeowners throughout the North Bay improve the safety of their electrical systems with dedicated circuits, surge protection, whole-house rewiring, and other residential services. We’ll carefully inspect your home’s current electrical setup, identify potential hazards, and recommend solutions to address them.

Never leave electrical safety up to chance. Contact us online today or call (707) 545-3300 to schedule a safety inspection with a fully licensed electrician.

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References

1. Mammone, S. (2025, February 20). Reaching to safety: Use extension cords properly. Electrical Safety Foundation International. https://www.esfi.org/reaching-to-safety-use-extension-cords-properly/