Space heaters are one of the staple must-have appliances of any home or office building to fend of the frigid claws of the bitter cold months.

Not only are these portable units capable of warming up select spaces in both indoor and outdoor areas, but these devices also come in a variety of shapes and sizes which are tailored exquisitely to individual preference.

With the jagged peaks in electricity bills getting higher and steeper with each passing year due to elevated living costs worldwide, space heaters have provided an almost economical advantage in reducing the overall heating costs of a house or common building.

However, this does not mean you will be immune to a hike in your electricity bill.

It simply means that using a space heater rather than a centralized, built-in heating system will see a long-term reduction in your overall heating bills.

Since most space heaters are powered by electricity, they come equipped with a miscellany of electrical-based features and components, including fuses.

But what exactly are fuses? Why do spaces heaters need them, and why are they crucial to the operation of any electrical appliance for that matter?

What Are Fuses in Space Heaters Meant For?

A fuse generally functions as a safety device that serves as a barrier of protection against an overflow of electrical current in electrical appliances and devices.

Space heaters are among the top electrical devices to overheat easily, especially when used for a prolonged period of time or are not installed or maintained correctly.

An overheated space heater is dangerous because it can double up as both a safety and fire hazard or in some severe cases, even explode unexpectedly in bits of plastic and metal.

Fuses in space heaters usually come with a rated current of 8 to 15 Amperes (A), and a rated voltage of 120 to 240 Volts (V).

The thermal cut-off for these fuses usually occurs through both radial and axial leads.

In the event that a burst of electrical current surges through your space heater, the fuse will melt and this will immediately stop the electrical current from continuously flowing through your device.

This is vital since an overcurrent can inflict severe breakage and damage to the other sensitive internal components of your heater such as the heating elements and thermostat, or even ceramic plates in the case of ceramic-based electrical heaters.

What Causes a Fuse to Blow Out in a Space Heater?

The electrical grid that supplies every home or occupied building in various parts of the globe is protected by a series of either fuses or circuit breakers.

If your space heater blows fuses in your home, stop using it immediately. Continuing to overload your wires will generate excess heat, which will in turn melt the plastic and ignite your wires.

The same principle is applicable to most modern-day devices such as space heaters, which often utilize fuses rather than circuit breakers.

The fuse that is nestled safely within the plastic confines of your space heater is most likely the screw-in type – meaning, it either consists of ceramic or glass cylinders which come screwed-into complementary sockets.

The main cause of a fuse melting is an over-surge of electricity coursing through the space heater, as discussed earlier.

This often occurs when the space heater is plugged into a power strip rather than a direct electrical socket, or when a natural event such as a lightning storm occurs when the space heater remains plugged in.

Either way, such incidents may cause a fuse to blow out immediately, and prevent your space heater from functioning altogether.

How Can You Prevent Your Space Heater Fuse from Blowing Out?

There are numerous precautions you should take into account to prevent the fuse in your space heater from blowing out prematurely. These safety measures include:

1. Stop Overloading Your Circuits

A circuit overload is one of the root causes for a fuse melting or blowing out in a space heater. In most cases, the circuit cannot handle the amount of current circulating through the grid.

For example, if you are using a space heater with a power output of 3000 Watts, you will need to ensure that the circuit can handle the amount of power consumed by your heater.

Simply put, the circuit load must not exceed the amount of power the circuit can cope with.

If you are unsure about how much power the electrical circuit in a specific room in your home can handle, you may consult an experienced electrician to help you determine the exact maximum amount of power that can be transfused through the grid.

You must also try to avoid using the ‘daisy chain’ method of wiring if possible. This method of wiring utilizes a looping sequence that is the same across multiple outlets.

Although this sounds and looks economical space-wise in terms of wiring, it can present an enormous strain on the overall electrical payload and double as a terrible fire hazard if performed incorrectly.

Therefore, it is highly inadvisable to utilize this method, no matter how much wiring space you intend to save.

Overloading a circuit with multiple space heaters or an ill-fitted space heater in terms of power is also a major no-no because this can cause your circuit to trip, the fuse in your space heater to melt, or in worse cases, can even turn your precious humble abode into a fiery statistic on the news.

2. Check Your Wiring

Stay on your toes and always monitor both the internal wiring of your home as well as the external wiring of your space heater for any defects or damages on a monthly basis.

Ensure the wiring is properly done.

Look out for any signs of fraying or even breaks in the protective rubber casing tubing the wiring.

If you notice any oddities, immediately contact your electrician and do not plug in your space heater until the problem has been resolved.

Faulty wiring can result in an upsurge or sporadic bursts of current which can damage any connected electrical devices, including your space heater.

In the case of your heating unit, the fuse will most likely melt in an effort to preserve the other components of the heater from further damage.

Sometimes, continuous exposure to an overcurrent will elicit more damage in the sub-units of the heater even though the fuse has melted.

Therefore, it is always recommended that you stay alert and keep your eyes peeled for any noticeable abnormalities in the wiring of your home, as well as the wiring of your space heater.

If your heater is brand new but has a damaged cord, then it might be the result of a manufacturing defect and the entire unit will need to be returned to the store for either evaluation or repair, or maybe even total replacement.

3. Check Your Amperage Limit

A 120V space heater, in general, uses anywhere between 8 to 13 Amps tops. Due to the variability in type, size, design, and model found in space heaters, it is vital that you take note of the maximum amperage limit of your device.

The maximum amperage limit can be discovered using the simple formula of:

Both the wattage (W) and voltage (V) of your space heater can be found stamped on a label located either at the back or the side of your device.

If the information is not located there, then you may browse through the owner’s guidance manual of your space heater to discover the exact power of your space heater in terms of Watts (W) and Volts (V).

Once you have determined the Wattage and Voltage of your space heater, you can calculate the Amperage of your unit.

For example, a 1500 W heater with 120V will have a rated amperage of 12.5 Amps.

This means that the fuse inside your space heater will melt if exposed to a current that exceeds 12.5 Amps as a protective measure to safeguard your device from further malfunction.

4. Avoid Extension Strips

Extension strips should not be favored over direct electrical sockets when it comes to plugging in your space heater.

Avoid using a extension strip to save space heater from blowing fuse

Since space heaters use an average of 1500 Watts to operate (larger units will, in fact, demand more power than this), using a heating device of this power range would require its own circuit to run.

Extension strips prompt the usage of multiple electrical devices plugged into a single strip which is then fed back to a single outlet.

Each device adds its own ‘load’ to the circuit and burdens the grid looping to it. With more and more devices connected to the strip and adding on to the ‘load’, the overall ‘payload’ of electricity becomes too immense and this can cause an overcurrent, which will then trigger the fuse in your space heater to blow out.

It is recommended that your device contributes to a maximum of 80% of the circuit load capacity at any given time.

This means that a circuit loop of 20A should not have an exceeded current usage value of 16A. As calculated earlier, a 1500W space heater usually has an amperage of 12.5A.

Therefore, you cannot plug in two 1500W space heaters into the same extension strip that leads back to a single socket with a rating of 20A and expect the fuses in both of these space heaters to hold.

5. Unplug Unused Electrical Devices and Appliances

All unused electrical devices and appliances still have a certain amount of electrical current circulating through them, especially when they remain plugged in.

The same goes for electrical space heaters. Even while not actively in use, a space heater that is plugged into an electrical socket will still have a small fraction of current streaming through the device.

Now, imagine plugging in multiple devices including your coffee maker, your refrigerator and your space heater into a single electrical outlet, with all the devices and appliances turned off.

Each device and appliance will contribute to an existing payload of electricity that loops through the electrical grid of your home.

Even though the amount of electricity running through the devices and appliances is minuscule as compared to when they are fully turned on, there is still a current surging through them continuously.

This continuous exposure to electricity will eventually lead to the fuse in your space heater to heat up, and possibly melt or char over time.

Thus, it is best to unplug any of your space heaters when you have no intention to actively use them.

6. Check Your Fuse

Servicing and maintaining your heater plays a large role in ensuring all components of the heater are preserved in terms of functionality and integrity.

This also includes the fuse located inside your space heater. Once every three months, it is recommended that you manually disassemble your space heater for routine cleaning and maintenance.

Fuses can be checked quite easily using a multimeter.

Once you unscrew or remove all the screws, clips or fasteners that hold the exterior plastic casing of your space heater to its internal housing, do not forget to take a peek at the fuse as well.

Look out for any signs of discoloration, melting or even charring.

A blackened or broken fuse will need to be replaced with a new fuse with the exact same specifications as the old fuse.

Make sure the new fuse also carries the same Amperage (A) rating as the old fuse, since a misuse of fuses could result in too much electricity flowing through the heater the next time it is turned on, and this, in turn, might cause the other internal sub-units of your heater to sustain damage or breakage.

If you are unsure over which fuse to attain to replace your older, charred fuse, simply take the melted fuse to the store and request the aid of the store assistant to help you find a new suitable fuse that is an identical match for your damaged fuse.

In the event you are unsure about how to replace the fuse yourself, you may request the assistance of a professional heater serviceman to do it for you.

7. Give Your Space Heater a Break

Running your space heater for a prolonged period of time without any downtime in between is not exactly the brightest idea.

All electrical devices heat up tremendously if they are left switched on for hours upon hours without any rest. Your space heater is no different.

When you leave your space heater running continuously, the internal core temperature of the device will skyrocket and most likely exceed the threshold temperature stipulated by its manufacturing guidelines, as outlined in your owner’s manual which comes attached with your space heater upon purchase.

The excessive heat will eventually cripple some of the internal mechanisms of your heater – your thermostat is most likely the first to blow in this case, followed shortly by the fuse, which will try to melt to shut down the heater in an effort to prevent it from overheating any further.

Therefore, it is best you do not use your space heater for more than eight hours continuously at any length of time or day.

Always monitor your space heater – if it starts fuming or downright smoking, immediately switch it off and unplug it from the electrical socket.

An overheated space heater is a dangerous space heater.

Not only is it a potential fire hazard, but it can also pose as a safety risk, especially if you have pets or small children that might accidentally brush a paw or a curious finger against the burning exterior of the heater.

If you truly wish to preserve the fuse in your space heater, you must allow your device to rest from time to time.


Thus, by following the precautionary measures outlined above, you can prolong the longevity of the fuse in your space heater.

Remember, if the amperage of your space heater exceeds the rated amperage of your electrical socket on the wall, do not plug in your device!

Not only will this result in a short circuit and a fuse blowing out, but it can also start a fire or turn your space heater into a major shock hazard.

Always go the extra mile in ensuring the safety of you and your loved ones at all times.