Can a Space Heater Be Plugged into an Extension Cord? 

As the temperature drops during the cold months of winter, you are bound to feel the need to crank up the heat in your home. Space heaters offer a more portable and cost-effective solution than traditional heating systems. However, if you decide to install one, you must be cautious about where you plug it in.

Space heaters tend to draw a high amount of electricity and are likely to overheat an extension cord and cause an electrical issues. It’s recommended that you only plug your space heater into a wall outlet, but if you need to use a strip, pick one with a built in switch and fuse to add safety.

Many fires have been started by an overloaded extension cord overheating when a high-power appliance like a space heater is plugged into it. This article will explore the potential hazards of using an extension cord or a power strip for a space heater. We will also highlight the safety precautions you need to take if you decide to use an extension cord anyway.     

Can an Extension Cord Safely be Used for a Space Heater?  

Heating surface of oil heater is on foreground and home space is on background

Extension cords are widely used to bring power to many electrical devices. However, plugging your space heater into one exposes your home to unnecessary danger. This is mainly because space heaters draw more power than most extension cords can handle.  

A medium-sized space heater can draw up to 1,500 watts and 12.5 amps or more. Most extension cords have an average rating of 10A to 15A. This means that even if your extension cord is seemingly able to handle the high amounts of current needed to power a space heater, any power fluctuations could overload it. 

The heat generated by the high current could melt the insulation and ignite the cable leading to a fire outbreak. Such occurrences have contributed mainly to space heaters accounting for up to 16% of the total home fires in the US, according to the National Fire Protection Association (NFP).    

The Dangers of Using an Extension Cord for a Space Heater 

Plugging space heaters into extension cords has many downsides besides the cords’ inability to handle high current. Such a connection can expose you and your household to numerous hazards.

Since space heaters use a lot of electricity, and their heating elements can achieve temperatures of up to 600 degrees F, accidents can be fatal. Some of the dangers that you may face if you plug your space heater into an extension cord include: 

Tripping Hazard

Extension cords are generally long. They are also not hidden in the walls like permanent wiring installations since they should be visibly placed for safety reasons. If they are in a high-traffic area, they become a trip hazard. This is more dangerous if you have kids or pets.

Tripping over an extension cord connected to a space heater may cause you to fall and hurt yourself. It may also tip the heater over and damage it or trigger a fire if it falls on combustible objects. Even if the heater automatically turns off after tipping over, it will take time to cool and could still cause a fire.

Risk of Increased Current

Space heaters typically have power cords that are long enough to be used without relying on an extension cord. Adding an extension cord to the connection increases the current’s distance from the wall outlet to the heater. The longer distance also increases the resistance to current flow, and this causes a voltage drop. 

An average space heater draws approximately 1500W of power. Power equals voltage multiplied by current. As such, a voltage drop will increase the current to compensate for the power needs of the heater. When the extension cord is forced to deliver higher currents, it may overheat and cause a fire.

Risk of Electric Shock

Using an extension cord increases the connection length from the wall outlet to the space heater. In addition, the large surface area increases the risk of electrocution, especially if there is a chance of water or snow coming into contact with the extension cord.      

Reduced Efficiency of the Space Heater 

Space heaters rely on having a steady supply of strong power. As mentioned earlier, introducing the long extension cord between the wall plug and the space heater increases resistance to the current flow. 

To compensate, more power will have to be drawn so that the required amount reaches the space heater. In addition to the fire risk, the increased power supply will raise your electricity bill in the long run.  

Safest Types of Extension Cords for Space Heaters 

Plugging your space heater into an extension cord is not advisable because of all the safety concerns highlighted above. However, in some instances, you may not have a choice.

For example, the wall outlet may be too far from where you need to position your space heater, and using an extension cord to bridge the gap may be the only viable option. 

If you must use an extension cord to deliver power to your space heater, you must mitigate the risks of using a heavy-duty extension cord. Such cords are made of thick cables that can handle large amounts of electrical current without overheating. 

The thicker the cable, the better. A 14-gauge heavy-duty extension cord should safely power your average space heater pulling around 15 amps. 10–12-gauge cords may work as well.   

Safety Measures to Take when using Heavy-Duty Extension Cords on Space Heaters

A 14-gauge extension cord may be relatively safe for a space heater, but some risks are still involved. To mitigate these risks and improve your safety, there are several measures that you can take. These include: 

Identify Anomalies

You need to observe the extension cord connection carefully to identify any red flags as they appear. These include frequent tripping when the space heater is running or heating the extension cord.

These are signs of overloading. When the circuit is overloaded, the breaker trips to prevent electrical fires. 

A thick cable stays cool since it has a large diameter for the current to travel through. So heating could mean that the manufacturer cut corners by using a lot of insulation and thin copper wires to make the extension cord look thick.

Reduce Your Space Heater’s Power Usage

With modern space heaters, you can regulate power usage. Depending on the situation, you can switch between 750 and 1500 watts. When your heater is plugged into an extension cord, you should maintain the heater’s power usage at 750 watts.

A regular extension cord can handle 75 watts safely, so the margin of safety when using a heavy-duty extension cord will be large enough to accommodate power surges.        

Do Not Cover the Extension Cord

Transmitting large amounts of power may cause the extension cord to heat up. This is why extension cords should be left exposed and not run under a carpet or rug. Covering them prevents the heat from escaping increasing the chances of overheating and fire.   

Keep the Extension Cord Short

Despite their thickness, heavy-duty extension cords will still cause some resistance to the flow of current. As such, you should keep the cord short to avoid high resistance, which results in increased current and fire risk.   

Prioritize Extension Cords with Grounded Plugs

Grounded plugs have three prongs. Grounding provides additional protection from electrocution in case the space heater malfunctions. You should note, however, that a grounding extension cord is only helpful if your space heater has a grounding prong.  

Can I Use a Power Strip for my Space Heater? 

Every winter, fire chiefs warn about the dangers of plugging space heaters into power strips. This is because such connections often result in fires erupting.

Like extension cords, power strips cannot safely transmit the large amounts of current required to power a space heater. So using a power strip for your space heater is arguably more dangerous than using a regular extension cord.   

A power strip delivers the minimum power requirements of a space heater. Plugging in other devices in addition to the heater further increases the risk of the cable overheating, a fuse melting, or fire erupting. If you have to use a power strip, get the thickest one you can find. 

Other Safety Tips for Owning a Space Heater

Household electric convector for space heating

Space heaters have a reputation for being fire hazards. According to a Consumer Product Safety Commission report, they are responsible for more than 1,000 home fires annually.

This, however, does not mean that you should not add some warmth to your home during the cold season. Instead, it should only caution you against being reckless when using a space heater. 

In addition to plugging in your heater directly to a wall outlet instead of an extension cord or power strip, there are other safety tips that you should follow to avoid injury or worse when using the unit. These include: 

Never Leave Your Space Heater Unattended

Space heaters may not have an open flame like candles, but they have heating elements whose temperatures can rise to 600-degree F. This makes them a severe fire hazard. Do not leave the heater unattended, especially when you have children or pets around. 

Remember the Three-Foot Rule

There should be no objects within three feet of your space heater. The clearance helps reduce the risk of fire. 

Choose a Reliable Model

When shopping for a space heater, consider a reputable brand whose products have been approved by an independent testing laboratory. 

Be Mindful of Placement

The safest place to place a space heater is on the ground. The ground should be flat and smooth. Avoid placing it on the carpet, shelf, or near flammable material.  

Final Thoughts

Using a space heater to warm your home during the cold season is reasonable. But, sadly, many people put their lives and property at risk each time they use a space heater. This is because they plug their heaters into extension cords or power strips. 

While circumstances may force you to use an extension cord, you must be careful to use a heavy-duty extension cord with the correct gauge and follow the safety precautions highlighted above.

Ultimately, it is essential to note that extension cords are intended to be used as temporary wiring solutions. Therefore, you should find a way to plug your space heater directly into the wall outlet as soon as possible.