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6 Reasons Why Electric Heater Plugs Get Hot

Electric heater plugs are likely to get slightly warm, especially when such appliances operate for several hours continuously. However, these plugs shouldn’t get hot to the extent that you can’t touch them. Thus, you need to know why electric heater plugs get hot and address the problem.   

Here are 6 reasons why electric heater plugs get hot:

  1. Defective plug 
  2. Bad receptacle
  3. Unsuitable wires
  4. Improper circuit
  5. Extension cord
  6. Arcs and shorts

Some of these problems call for extensive inspections of the electrical circuit and wiring in your house or a room. Hence, you may need to consult an electrician if you can’t detect the problem. Keep reading to understand the reasons why electric heater plugs get hot and solve the issue.

1. Defective Plug

Ideally, electric heater manufacturers should provide a UL-certified plug rated for the voltage and amperage requirements. However, some electric heaters don’t come with a plug. Often, these units are larger and require a 240V outlet, so your standard 120V receptacle won’t work.

If your electric heater has a plug provided by the manufacturer, it is unlikely to be incompatible with the appliance. Still, there is a possibility of the plug being defective. So, check whether the manufacturer has recalled any of its products or related components that may include yours.

Additionally, some affordable electric heaters may not have high-quality plugs. These plugs may not be defective straight out of the factory. However, glitches can cause electrical transmission issues in due course. Hence, you must check if the plug is UL-certified and visibly in impeccable condition.

If you have used an aftermarket plug, you should verify whether or not it is rated for the voltage and amperage requirements of the electric heater. Furthermore, inspect an aftermarket plug to be sure that it doesn’t have any structural damage, such as deformed prongs or pins.

Here are a few defects that can make an electric heater plug get hot:

  • The plug’s connection at the outlet is loose due to a poor fitting or worn out receptacle.
  • The heater’s plug has high resistance due to rusted, corroded, or deformed prongs.
  • The wires in the plug are loose, frayed, damaged, or unsuitable for the electric heater.

The fundamental reason for electric heater plugs getting hot is the same for all these defects. If a plug or receptacle and the wires involved pose higher resistance, more electrical energy will get converted to thermal energy. Thus, the plug won’t just get warm but turn hot to the touch.  

A loose connection increases resistance, and so does rust or corrosion. Likewise, frayed wires inside a plug won’t transmit electricity as flawlessly as they should. Besides, loose connections or frayed wires cause electricity loss, a waste that heats up the components, like the plug.

Your electric heater will continue to draw or demand the required amps. If a loose connection or anything else leads to loss of electricity, the amp draw will spike, which can further increase the heating up of the plug and other components, including the receptacle.

If you have a defective plug, select one of the following remedies based on the flaw:

  • Use steel wool to clean the plug’s prongs and remove any rust you may find.
  • Disassemble the plug to check if the wires inside are frayed, loose, or damaged.
  • Cut off the broken parts of the wires and fit them snugly into the three terminals.
  • Tighten the terminals inside the plug and ensure the pins are properly aligned.
  • Check if the plug is rated per the volt and amp requirements of the electric heater. 
  • Get a new plug if the current one is beyond repair or incompatible with the appliance.

In the United States, the appropriate standard for plugs is UL 498 or UL 60320. Ensure your plug is certified accordingly. You will also need to match the wattage or amp draw of your electric heater, but if the plug is alright, you have to inspect the receptacle.

2. Bad Receptacle

Like the plug’s prongs or pins, the receptacle’s metal contacts are also vulnerable to the same issues. However, a bad receptacle is easier to infer if the plug isn’t defective. 

You can use the plug on another wall outlet to check if it gets equally or nearly as hot. If the plug doesn’t get hot, the previous receptacle has a problem. Some issues are rectifiable, but a very old wall outlet may be past its prime. Nonetheless, you can inspect the receptacle’s condition.   

Here are a few typical issues with residential power receptacles or wall outlets:

  • The metal contacts inside the socket are misaligned or loose.
  • The contacts are rusted, corroded, or structurally damaged.
  • The wires at the terminals of the socket are loose or frayed.
  • The wires are fitted to the tiny holes at the back of the socket.

An alignment or fitting problem should be evident when you insert and remove the plug. You’ll find that the plug won’t have a snug fit. So, it may hang loose. The plug will also come off easily, without much effort or wiggling. 

Contemporary plugs have holes in the prongs, while the receptacles have bumps to grip those pins. Some receptacles have springs inside to grip a plug without the holes in the pins. So, if these bumps or springs don’t work as they should, your electric heater plug may be loose.

A loosely fitted plug increases the resistance due to less contact with the metal conductors. This spike in resistance generates heat. In effect, your plug can get hot, and so can the receptacle. In contrast to this fitting issue, the other problems require a closer inspection. 

For instance, the wires fitted to the terminals at the back of the wall outlet or receptacle may be loose and frayed. The fraying or loosening can happen due to years of use or a lot sooner when you use appliances like an electric heater that draws a lot of amps.

A common practice exacerbates this wiring problem. Many people fit the wires into the tiny holes at the back of a receptacle. Such an installation works fine for appliances that don’t draw as much electricity as an electric heater. However, this practice can cause the plug and socket to heat.

A high amperage draw leads to greater expansion and contraction of the wires. Since the wires make very little contact when they are fitted into the holes, the expansion and contraction loosen the connections. In some cases, the wires may lose much of the contact with the terminals.

Therefore, an increase in resistance causes the heating problem. An appropriate counter to this phenomenon is wrapping the wires, at least the live one, around the terminal screw. This tactic increases the surface area in contact. Additionally, the wire is fastened much stronger due to the screw.

That said, don’t let the wire’s insulation get under the small securing plate. Strip away enough shielding or insulation to have only the wire under the screw. You can inspect a socket for these problems after turning off its circuit breaker, or consult an electrician if you aren’t comfortable.

Here’s a standard approach to inspecting a receptacle if your electric heater plug gets hot:

  1. Turn off the circuit at the breaker or fuse before accessing the particular receptacle.
  2. If you’re unsure about the specific breaker, use a tester to check if the outlet has power.
  3. Take the receptacle off the wall and inspect the socket for visible signs of damage.
  4. Check the metal contacts, wires, terminals, screws, mounting plate, and bumps.
  5. Receptacles without bumps to grip the holes of a plug’s prongs may have springs.
  6. Clean the rust and corrosion from the metal contacts with emery paper or steel wool.
  7. Ensure all the wires are comprehensively and snugly fitted to the different terminals.
  8. You may find loose or frayed wires at the terminals due to years of use, heat, and wear. 
  9. Cut off any frayed parts of the wire and wrap them around the terminals properly.
  10. Strip sufficient shielding or insulation for the wires to make full contact with the terminals.
  11. Also, you will be able to tighten the screws properly if there’s no insulation underneath.
  12. If you’re rewiring, ensure the live wire is installed on the terminals with the brass screws.

Don’t put the live wire into the tiny hole at the back of the socket for appliances like an electric heater. If you are replacing an old receptacle, ensure the new one is UL-certified, as cited above. The alternative federal specification is W-C 596F or W-C596G.

3. Unsuitable Wires

Your electric heater plug interacts with two sets of wires. One set is in the power cable, while the other is in your house or room, connected to the wall outlet. Both these sets of wires should be rated for substantially higher than the maximum amperage your electric heater requires. 

Let me use the example of a 120V electric heater rated for 1,500 W. This unit will draw around 12.5A in high heat mode. The actual amp reading may be slightly lower or higher. Suppose the real time current consumption is ~13A. Your wires should be compatible with this amperage.

Now, in theory, a 14 AWG wire should transmit 13A without overheating. However, if the wire is of poor quality, the net current transmission can drop to lower than 10A. And I’m talking about power transmission, not the maximum amperage of the different gauges for chassis wiring.

If the net current transmission is insufficient, your electric heater will draw more electricity. So, the wires, circuit, receptacle, and plug will get hotter. As the entire system gets hotter, there is an immediate impact on resistance, as it spikes as well. Thus, you have an overheating issue.

Therefore, using 12 AWG wires may be better. Generally, 12 AWG wires are fine for the power cable and plug of an eclectic heater rated for 2,500 W and a bit more. However, these larger electric heaters run on 240V

Nonetheless, using a better gauge wire than the minimum you need is always safer, especially if electric heater plugs get hot. So, you can get 10 AWG wires if you don’t want resistance issues.  

4. Improper Circuit

Like the wires, your electrical circuit plays a vital role in a plug getting too hot. 

Generally, homes have 120V circuits with 15A or 20A breakers. So, a breaker won’t trip until all the energy consumption in a particular circuit is more than the capacity. In effect, the unsuitable wires can keep drawing in more electricity with a lot more resistance until the breaker trips.

Terminal voltages of any electrical circuit don’t remain static all the time. Your 120V circuit may read 110V, and that could be the long term average. At 110V, your electric heater will draw a bit more current than in a circuit that is steady at 120V (I’m excluding the 240V models here). 

In other words, electric heaters are likely to draw more electricity at lower terminal voltages and with wires having greater resistance. Hence, there’ll be more heat generated at the receptacle or the plug. The wires’ overheating is shielded by insulation, so you won’t get to know or feel it.

Large space or electric heaters demand a dedicated circuit. If you don’t have one, the appliance may not work efficiently. The inefficiency compels the unit to draw more electricity, which leads to greater resistance and more heat. As a result, your electric heater plug gets too hot.

These circuit or wiring issues are somewhat complicated if you aren’t familiar with your electrical setup. Ideally, you should consult an electrician if you think the circuit, wires, and breaker aren’t suitable for your electric heater.    

5. Extension Cord

You shouldn’t use an electric heater with an extension cord. If you must, use an extension cord that is rated for the requisite amps. The extension cord or power strip should also be grounded. So, get an extension cord or power strip with 3 prongs, and the max amps draw of the heater.

6. Arcs and Shorts

Last but not least, arcs or shorts can cause your electric heater plug to get hot.

Arcing may not be an issue if you have arc fault circuit interrupter (AFCI) receptacles. However, even AFCI and AFDD outlets may not detect all arcing issues. Also, a short in the wiring, outlet, plug, or electric heater may cause unusual heating.

Many people unplug electric heaters by holding the cables, not the plug. This action may affect the wires inside the plug. If a live wire finds a medium or quicker path for transmission, you may have an arcing issue or a short to deal with, although the two aren’t the same.


  • Jake Alexander

    Jake is a freelance writer from Pennsylvania who enjoys writing about science and sports. When he's not writing for Temperature Master, he can be found watching the NFL or playing basketball with his friends.

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