How To Prevent A Space Heater From Blowing A Fuse (5-Step Guide)

If you continuously struggle with space heaters blowing fuses in your home and you’re looking to find out why, and stop it from happening again, you’re in the right place!

In this proHVACinfo guide, we’ll be learning about:

  • What you need to know about space heater fuses (these are essential safety devices)
  • How to prevent a space heater from blowing a fuse (follow these simple, but effective steps)
  • And much more!
proHVACinfo | How to Prevent Space Heater from Blowing Fuse

What You Need To Know About Space Heater Fuses

Unlike in other countries North American space heaters don’t actually feature a fuse in their plug, and modern homes are not even fitted with fuses any more.

So, when we refer to “blowing a fuse”, we’re actually talking about tripping the breaker of the circuit your space heater is attached to.

Your home’s electrical system is built up of a number of circuits, each featuring its own breaker, designed to trip under certain conditions to prevent electrical fires.

So, why do space heaters blow fuses or trip breakers? While there are dozens of potential reasons why, these are the usual suspects when it comes to space heaters:

Current Overload

Time and time again, excess current is found to be the primary cause of space heaters blowing fuses.

The circuit can only handle so much current, so, if the breaker’s maximum is exceeded, the circuit will be broken as it trips in order to prevent an accidental fire.

This can occur when industrial tools that require more power than domestic tools are plugged in, for example.

For your reference, household circuits are rated in amps, which is short for Amperes. Amps are a standard measure of electrical current.

Typical household circuits are rated for either 15, 20, 30, or 40 amps.

The majority of outlets in your home will be on a 20 amp circuit. With that in mind, consider the following – you start with 20 amps and plug in an iron that draws 12.5 amps, you then turn on your space heater, which also draws 12.5 amps – you’re now pulling 25 amps on a circuit designed for 20 – a recipe for blown fuses.

You can work out how many devices it’s safe to use on the same circuit by looking for the amp rating on the electrical info sticker on the appliance, but any case, it’s always safest to run as little load on each circuit as possible.

Excessive Appliances On A Single Circuit

Another frequent cause of blown fuses is the use of too many devices, even small ones, on a single circuit.

Again, excessive numbers of appliances will draw excessive current, and this will cause the breaker to trip as a failsafe.

Underrated Breaker

It could be the case that the breaker installed is simply underrated.

You may need to replace it with a larger breaker that is capable of handling more power.

This should really be taken care of by a licensed electrician, but it’s often the case with older homes as there were usually fewer electrical items in use back when the house was built.

An easy way to tell if this is the case is to feel the breaker switch when it’s operating under normal load – if it feels warm, there’s a good chance it is not an appropriate size.

No GCFI Plug Installed

In the event that the fuse breaks or breaker trips are being caused by ground faults, and there is no ground fault circuit interrupter plug on your space heater, the circuit breaker is the last line of defense, and will trip to prevent potential shocks or fires.

How To Prevent A Space Heater From Blowing A Fuse

Next, we’ll learn the steps you need to take in order to prevent frequent blown fuses or tripped breakers.

Step 1: Isolate The Space Heater

The first thing you should do is establish the cause of the trips.

If you have multiple devices plugged into the same circuit as the space heater, there’s a good chance that it’s simply overloaded.

Regardless of whether you’re even using the other appliances, if they have a standby mode, they are using electricity. 

So, ensure that your space heater is the only appliance that gets plugged into the outlet you plan to use it on.

Step 2: Inspect The Power Cord

An important point to note, is that no matter the condition of the space heater, be it 15 years old or brand new, it should never be plugged into an extension cord, even if it’s the only device.

Extension cords simply aren’t able to stand up to the rigors of supplying power to a space heater, which leads to overheating and fire.

Before plugging your space heater directly into the outlet, check the power cord for damage. Any kinks or breaks in the insulation could be causing shorts, which will often be the cause of fuses blowing.

If you find any damage to the cord, stop using the heater immediately and have it rewired.

Step 3: Switch To A Lower Power Setting

Many space heaters come with 2 power settings, 1500w and 750w. If you’re using the 1500w setting and you frequently trip the breaker, try using the 750w setting.

If it provides enough heat and doesn’t blow fuses – problem solved! Not only will you be preventing frequent breaker trips, but you’ll also be spending less on energy, too.

Step 4: Upgrade Your Space Heater

It’s a sad fact that electronic appliances are simply not designed to last forever, especially space heaters.

If you’re having a lot of issues with blown fuses and tripped breakers, and your heater is more than 5 years old, it could be time to think about replacing it with a new one.

This is especially true for anybody who uses their space heaters regularly.

The easiest way to detect whether the fault is with your heater, rather than the wiring is if it blows fuses no matter which outlet you plug it into.

Check out our reviews of the best bathroom and basement space heaters to learn more about the best units on the market.

Step 5: Hire A Professional

At proHVACinfo, we like to provide our readers with the knowledge to take on jobs themselves, but when it comes to some things, we will always tell you to seek professional help.

When it comes to electricity, the risks are too great to just have a go and hope for the best.

If after trying all of the tips in this guide, you still haven’t had any luck in preventing blown fuses or tripped breakers, call a licensed electrician to inspect your home’s wiring.

Final Thoughts On How To Prevent A Space Heater From Blowing A Fuse

With electrical safety, room for error is almost nil. While it might be tempting to reach for the extension cord in order to run your space heater closer to your favorite chair, this could be a disastrous move.

Learning how to avoid blown fuses shouldn’t just be for avoiding the minor inconvenience of trips to the garage to reset the breaker, it should be about how to run appliances like space heaters more safely.

Stephen Marks

Stephen Marks

Stephen is an HVAC and home-repair enthusiast. He's here to answer any of your questions about HVAC!

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Stephen Marks

Stephen Marks

Stephen is an HVAC and home-repair enthusiast. He's here to answer any of your questions about HVAC!

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