Can a Microwave be on the Same Circuit as Other Appliances?

Remodeling a kitchen can be difficult right from the design phase, to the tiling, and even to safety concerns. But among the most difficult parts of remodeling or building, a kitchen is the wiring: if you get it wrong, your appliances may not work or they may overload. With that in mind, can you put your microwave on the same circuit as your other appliances (stove, refrigerator, etc.)?

A microwave should typically be on a separate circuit from the rest of a kitchen’s appliances. If one’s appliances have unusually small power requirements, one might be able to place them on the same circuit, but otherwise, it can cause fires or trip the circuit breaker.

The specifics about why you probably shouldn’t use a microwave on the same circuit as other appliances will be explained in the rest of this article. Read on to find out if and why you shouldn’t.

Why Can’t a Microwave (Usually) be on the Same Circuit as Other Appliances?

The reason a microwave can’t be on the same circuit as other appliances is relatively simple: appliances draw large amounts of power, and a typical home electrical circuit only has so much power to offer. In a home that receives the typical 120 volts of electricity, a 15 amp circuit (which is also typical; some homes have 20 amp circuits though) can safely allow for the use of 1800 watts of power. When the same circuit has an appliance that is run continuously for over 3 hours (such as a refrigerator), this safe limit is reduced by 20%, to 1440 watts.

Now, a 20-amp 120-volt circuit can handle around 2,400 watts, or 1,920 watts if there is an always-on appliance connected. This does give you some leeway compared to a 15-amp circuit, although that power can get pulled pretty fast if you’ve got power-hungry appliances like a microwave connected. Most kitchens built more recently, say within the past 20 years or so, have 120-volt outlets, which gives you a lot more power. You could probably get away with an efficient microwave and refrigerator plugged into the same outlet. Most of the time though, you’re still going to want to get separate outlets/circuits for each appliance.

If you have a weird circuit, you can calculate the capacity by simply multiplying the number of volts your house is getting (typically an average of 120) by the number of amps of your circuit. This principle is known as Ohm’s Law, which put simply, is just amperage or amps (A) times volts (V) is equal to watts (W). If you have any two numbers in this equation, you can work forwards or backward to find the number you’re looking for.

Energy Demands of Common Kitchen Appliances (in Watts)

Dishwasher: 1,200-1,500

Coffee Machine: 1,000

Blender: 500

Electric Kettle: 1,200

Refrigerator Average Watts: 300-800 W

Garbage Disposal: 450

Oven-Electric: 1200

Toaster: 850

Microwave: 1,000

As you can see, the needs of just one fridge can require all of the power from a single circuit. It is for this reason that most people give the fridge itself its own circuit. This also helps to prevent the fridge from letting your food go bad during a brownout, in which less than the optimal 120 volts is reaching your home from the power company.

And of course, all of these power needs can vary widely. A typical microwave oven can use anywhere from 600 to 1,500 watts, depending on its cooking power, size, age, and more. And of course, there are dozens of different appliances that a typical person might be using in their kitchen at any given time, including mixers, blenders, pressure cookers, toaster ovens, electric griddles, waffle-makers, and more. Any of these can take more or less power than average.

It is for these reasons that a microwave should most likely get its own circuit or at least one without other large appliances on it. In fact, if your microwave is built in (such as an above-the-range microwave), then it will need its own circuit as per The National Electric Code. This will ensure the safe and efficient operation of both your microwave and other appliances.

The risks of overloading a circuit include shorts (a minor inconvenience), fires (a major inconvenience), and over the long term, damage to the wires and appliances you use after multiple shorts. It really is worth it to wire your kitchen the right way and avoid the kind of repairs that might be required if you don’t.

Ways to Get Around Using a Separate Circuit

Now, while it is certainly not recommended (and can definitely be unsafe if the breaker fails to trip before a fire starts instead), there are ways to avoid using a separate circuit for your microwave and other appliances. Some of these methods include:

  • Unplug your fridge from the wall when you use your microwave. Be careful to remember to plug your fridge back in afterward, as you don’t want your food to go bad! Now, using a fridge in combination with your microwave is particularly unrecommended, because if your fridge can’t pull enough power, your food will start to spoil early. And of course, if your fridge decides to turn on (your fridge turns on periodically throughout the day in order to maintain temperature) right at the same time as you’re using the defrost feature on your microwave, it may cause a short.
  • If your microwave is on a shared circuit, just don’t use multiple appliances at the same time. Now, if you calculate that your minor appliances won’t draw enough power to be a problem, then you can use them at will, but most of the time you probably won’t want to bother to do so. And of course, a minor short once-in-a-blue moon is usually not the end of the world.
  • Some small countertop microwaves don’t draw that much power. If your microwave is particularly energy-saver friendly, then perhaps you can get away with using it in conjunction with other appliances on the same circuit.

Can You Use a Microwave on a Power Strip?

Using a microwave on a power strip/surge protector is generally a bad idea. Even when a power strip is supposedly rated for 15 amps, the fact is that something as power-hungry as a microwave will draw right up to the limit of what the power strip can give. If a microwave overloads a power strip, then it can cause the plastic of the strip to melt or even an electrical fire! You should always plug a microwave into a grounded outlet that has the proper amperage.

Now, if you do happen to have a really high-quality power strip/surge protector that is rated for the kind of power draw a microwave has, just make sure not to plug other appliances into it. The same voltage limits discussed early still apply to a surge protector, and you don’t want to overload it.

However, the fact of the matter is that even if your power strip says it is powerful enough, it still is a lot less safe than using a wall outlet. In fact, insurance companies probably will be a lot more resistant to paying for damages caused by an electrical fire if it originated as a result of you using a microwave or other large appliance that is plugged into a power strip.

In the same vein, you should also avoid using an extension cord to plug your microwave into. Not only is there a decent chance that it won’t be getting the power it needs (and thus will cook your food more slowly), but there is also a chance of electrical fire. Once again, this won’t look good when it comes to insurance purposes. It is much better to just use a dedicated circuit and outlet for your microwave, as most of the time, it draws the most power out of almost any kitchen appliance you could get.

Can You Put Your Microwave on Top of the Fridge?

While it is still important to make sure your fridge and your microwave are on separate circuits, most of the time, it is ok to put your microwave on top of the fridge. However, there are some considerations that are good to keep in mind.

  • A mini fridge still uses a decent amount of power, so it is still not recommended to plug both a mini-fridge and a microwave into an outlet, although if they are both relatively power-efficient you may be fine.
  • Most microwaves vent heat out of the top and back, meaning that most of the heat will still vent away properly if the microwave is on top of the refrigerator. However, if the microwave was designed to be used in an enclosure originally, then it may be possible that it vents heat downward as well as upward and backward. This can cause damage to the top of your fridge if it is the case.
  • There is still residual heat produced by a microwave, that can interfere with your fridge’s ability to vent hot air properly. This extra heat may cause your refrigerator’s condenser to turn on more often, meaning a higher electricity bill. This can cause unnecessary wear and tear on your fridge.
  • Make sure that the top of the fridge is flat, and that it has enough space for your microwave. You don’t want your microwave to fall down as a result of faulty footing!

What to do if You Only Have One Kitchen Outlet for both Your Refrigerator and Your Microwave?

It is possible to have two circuits connected to the same outlet, as long as those two circuits don’t overload the outlet rating. Most outlets, however, draw power from the same circuit, and thus the two plug-ins are sharing the same circuit. This is bad news if you are trying to use large appliances such as a microwave and fridge on that outlet simultaneously.

However, it is possible, with the right know-how or with the help of an electrician, to separate the connection between the top and bottom half of an outlet, and then use some additional wiring to create another circuit. This can be somewhat complicated, so don’t hesitate to get an electrician to come to do it, as they are required to make sure that their work is up to code, and they don’t want to be held liable in the case that the wiring is faulty and causes excessive shorts or a fire.

International Considerations

Different countries have different standard setups for their electrical grid. Some countries typically have different voltages running to residential properties than our standard 120-volt setup. The amperage of an up-to-code circuit can also differ. If you are trying to use an appliance like a microwave that was made in or made for America, then you may have to check to see if the outlets where you are traveling or moving to are compatible, not to mention that you may need a converter in order to use it at all in the first place. If your appliance draws more power than an outlet can provide, it can cause all sorts of problems with the appliance itself, not to mention that it will trip the breaker.

Conclusion

Overall, the best and safest way to operate a microwave is with it plugged in directly (not with an extension cord or power strip) to a dedicated kitchen outlet, without any other appliances connected to the same electrical circuit. Microwaves just draw so much power that almost any other setup is inadvisable.

And although you can probably get away with using a smaller microwave on the same outlet as another smaller kitchen appliance, you don’t want to use both at the same time. Fridges and microwaves are also required to have their own circuit per U.S. electrical code. Using separate outlets and circuits will ensure not only that these appliances function at their highest capacity, but reduces the risk of fire or the annoyance of your circuit breaker going off every so often.