When Extension Cords Overheat: Causes, Fixes, And Safety Tips

There are extension cords everywhere: in the garage, powering equipment, in the living room, powering the television, and in the backyard to hold evening get-togethers. They are a popular solution when an outlet is a bit out of reach.  

However, as convenient as these cords are, they present a hidden hazard of overheating. Due to negligence, thousands of fires in homes and workplaces are triggered by overheated extension cords every year.  

That is because a warm extension cord might appear harmless, but it could be an indication of more serious issues with electricity. Speaking of which, as a DIY enthusiast, homeowner or office manager, there are several reasons why you need to know what leads to overheating and how to prevent it. 

Now then, let’s take a closer look at the underlying causes, possible solutions to the problem of overheating, and effective safety measures so that you can stay safe at your home and in the workplace. 

The Reason Why Extension Cords Overheat 

An understanding of overheating in the first place is essential before proceeding to learn how to fix it and prevent it. In this context, an extension cord may overheat due to a number of factors or combinations of them. 

1. Excessive Load on the Cord Capacity 

Each extension cord has an amperage or watt limit. When you connect devices that draw more power than this limit, the cord has to bear a stronger electric current than it was designed to support. This overloading leads to rapid heating of the internal wires.   

With the heat buildup, this may cause insulation around the conductors to deteriorate, possibly causing a short circuit with consequent arcing, or even fire. For example, if you use a heavy power-demanding appliance such as a space heater (1215 amps) with a light-duty cord rated at 10 amps. Such a mismatch is a disaster waiting to occur. 

2. Employment of Inferior or Underrated Extension Cords  

Low-grade or poor-quality extension cords might sound like a bargain at the time. However, they are usually improperly insulated, poorly wired with copper, or with unacceptably low safety standards. 

Such cords are normally crafted using inferior materials that are not suitable for regular or high-demand use. Consequently, they get superheated easily when connected to even slightly demanding gadgets.  

Furthermore, these cords are more susceptible to wear and tear, making them more likely to be damaged internally. This damage might not be easily apparent on the outside. That is why such underrated cords are prone to overheating when put under repeated or constant burden, which can cause a dangerous fire hazard. 

3. Twisting or Wrapping the Cord 

Extension cords are constructed in such a way that they release heat in the air as electric current flows through them. That heat is trapped when a cord is coiled, bundled, or stashed under rugs, mats, or furniture.  

In other words, the wiring and insulation material experience an inability to cool down, and heat accumulates, which further increases resistance within the core. It usually causes the outer jacket to feel warm or hot.  

Even worse, trapped heat can soften or melt the insulation on the cord, particularly at high current loads. For this reason, cords should always be completely uncoiled and exposed to ensure enough airflow and heat dissipation.  

4. Long-Distance Runs  

The longer an extension cord, the more electrical resistance it provides. This resistance brings with it a loss of voltage- i.e., the longer electricity has to travel, the more energy is lost as heat along the way. 

Later, this heat generation may be considerable in case you are operating a device that utilizes a large amount of current through a long cord. Furthermore, long cords usually come in connection with small-gauge wire, which further exacerbates the issue.  

An excessively long or improperly sized cord cannot distribute the power effectively, causing overheating and possible breakdown of equipment. To prevent this, select the short heavy duty extension cord, properly rated to fit your application. 

5. Physical Damage or Wear  

Any sort of physical wear may severely undermine the integrity of an extension cord. Cords can crack the outer insulation, be cut by sharp objects, or be frayed by bending and flexing over time.  

Such flaws can reveal the inner wires or cause loosening of connections within the plug. Also, bad cords can create resistance at points of weakness, and this may cause overheating to occur locally, arcing, or electric shock.  

That said, under certain circumstances, these cords can even continue to work, but the probability of a fire or short circuit is much higher. Therefore, check your cords before using them, and do not use a damaged extension cord, no matter how slight the defect. 

How to Know Your Extension Cord is Overheating 

It is important to understand the symptoms of excessive heat to avoid fire, equipment damage, or electrical shock. What to look out for: 

1. Warm or Hot Cord Surface 

An extension cord feels slightly warm during usage; it is normal. Nevertheless, when it gets too hot to handle, particularly along the length or in the plug ends, it is an indication of overloading or internal resistance. Eventually, too much heat may deteriorate insulation, bend connectors, or even cause the fire to break out. 

2. Smoky Odor or Scorching Marks