Many people ask this question because their microwave ovens are not as large as their refrigerators. As such, they do not understand why the microwave requires a dedicated circuit.
Do Microwaves Need A Dedicated Circuit?
Microwaves require a dedicated 20A circuit. Apparently, the requirements of a microwave are similar to those of any other heavy-duty appliance such as a refrigerator. You should also include AFCI protection.
Though, GFCIs are not necessary in this case because the outlets that microwaves use are normally positioned behind the appliance, which means that they are protected from water.
Why Does Microwave Require Dedicated Circuit?
1). Electrical Requirement
From what Spruce has said, it isn’t enough to place your microwave on a dedicated circuit. You should place the appliance on a 120/125V circuit with 12/2 NM wire. You also need a ground for additional safety. They attribute this requirement to the fact that microwaves are powerful devices that use an estimated 1500 watts.
Some microwaves are smaller and they do not draw as much power. However, the larger models use a lot of electricity and that makes them dangerous.
2). To Prevent Overheat & Fire
Every circuit has a breaker that combats overloading by tripping in the event of a power spike or surge. Spikes and surges can happen in situations where a particular appliance is drawing more power than the circuit can handle.
For example, on the one hand, modern fridges do not use as much power as their older counterparts. They are far more energy-efficient.
On the other hand, a refrigerator can multiply its energy consumption by four times or more whenever it starts. If that fridge is forced to share its circuit with other heavy-duty items, it will overwhelm the circuit whenever it starts up, causing the breaker to trip.
Microwaves pose a similar threat.
On their own, they already use too much power. But if you wired your home properly, a dedicated circuit can carry the weight of a microwave’s energy requirements.
If you connect other devices to that same circuit, for instance, coffee makers and dishwashers, you are more likely to overload the circuit, especially if all these appliances are running at the same time.
This will cause nuisance tripping. That is to say, the breaker will trip whenever you turn the microwave on. But that is the best-case scenario. The breaker is designed to protect you from the consequences of an overloaded circuit.
If the breaker fails to respond, the spike will cause the wires in the circuit to overheat. This will lead to a fire.
Some people will argue that their microwaves are far too small to make a dedicated circuit a necessity. But it is better to be safe than sorry. Rather than risking an electrical fire, you are better off attaching your microwave to a dedicated circuit.
3). To Limit The Number Of Outlets
It is worth noting that any circuit in your home can act as a dedicated circuit if the microwave is the only appliance connected to it. People think that a dedicated circuit can only have one outlet but that isn’t true.
Yes, it is safer to limit the number of outlets to one because it prevents other people from accidentally plugging more appliances into the circuit when your microwave is running.
But if you connect your microwave to any random circuit in your home, and you unplug all the other appliances, that circuit can safely carry your microwave’s load because it is technically dedicated.
The goal is to prevent the microwave from sharing a circuit with other items.
What Watt Microwave Need a Dedicated Circuit?
You should place every device with a rating of 1,000 watts or more on a dedicated circuit. This is especially true for appliances that you use continuously. Microwaves among the appliances need dedicated circuits.
Battery Equivalents has categorized microwaves accordingly: compact (500-800 watts), medium (800-1800 watts), and large (1200-1300 watts). You can safely conclude that medium and large microwaves require dedicated circuits.
Small or even older microwaves, the types that are not fixed in place, can get by without dedicated circuits because they don’t consume as much power.
NEC Code For Microwave Receptacle
NEC doesn’t specifically address microwaves. However, it has regulations and clauses that are expected to influence your decisions. For instance:
- The power that a device on a circuit consumes cannot exceed 80 percent of the rating of that branch circuit. For instance, if you have a 20A circuit, the connected device should use 16 amps or less.
- If you have a piece of equipment that is fastened in place, the equipment’s rating should be 50 percent or less of the amp rating of the breaker. For instance, if you have a 20A circuit, the appliance (if it is fastened in place) should use 10 amps or less.
What does this tell you? You have two considerations to keep in mind:
1). If you have one of those large microwaves that are built into your kitchen (in other words, fastened in place), that microwave’s amperage cannot exceed 50 percent of the branch circuit’s rating. For example, if you have a 15A circuit, the microwave can only use 7.5 amps or less.
2). If you have a portable countertop microwave that isn’t fastened in place, it can use up to 80 percent of the branch circuit’s rating.
As you can see, the power requirements of your microwave are going to influence your decisions.
You can’t place an in-built 14A microwave on a 15A circuit. That would break NEC rules.
You have two other factors to consider where microwaves and their circuit breakers are concerned:
1). Check The Local Rules
At the end of the day, the local building codes in your area supersede the regulations of the NEC. Local rules are typically informed by the NEC. Many of them agree with the NEC.
But local authorities have the option of setting regulations that differ from the NEC. Before you install your microwave, check the local codes to find out what they have to say about the issue.
2). Check The Manual
The manual is just as important. Many manufacturers will specify the size of the circuit breaker their microwave needs. They will also tell you whether or not you need a dedicated circuit. Listen to the manual. The manufacturer knows what they are doing.
They built the microwave, which means that they know the safest way to operate it.
What Size Circuit Breaker Do I Need for a Microwave?
The size and power requirements of the microwave will determine the size of the breaker. Basically, a 15 or 20A circuit is enough to run a microwave with 1000W. To run a 1500W microwave, you will need a 30A circuit breaker.
Let’s see a simple calculation:
20A can support a maximum of 2400W. The safe maximum is 1920W. Thus, 20A can easily support 1000W.
30A can support a maximum of 3600W. The safe maximum is 2880W. Thus, 30A can support microwave with up to 2880W
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- An average 1000W microwave requires 14A. A microwave can make do with a 15 or 20A circuit breaker.
- Microwaves are not continuous loads, which means that they can survive on 15 amps.
- No one uses their microwave for more than a few minutes. This makes them less of a danger than refrigerators which are always on. This is also the reason why some people can safely operate their microwaves on general (non-Dedicated) circuits without tripping the breaker or starting any fires.
- Some microwaves use as little as 10 amps, which is why they can get by with a 15A circuit breaker.
The amperage rating of the outlet should match the rating of the breaker. This will prevent premature tripping on the part of the circuit breaker.
Talking about a volt, even though American power supplies are 110/120V, they are more than capable of providing 220/240V if the need arises. That being said, 120V is more than adequate for a small appliance like a microwave.
Can a Microwave Be Plugged into Any Outlet?
You can plug a microwave into any outlet. The appliance doesn’t require a special receptacle. It doesn’t need GFCI protection either. Though, AFCI protection is recommended. Unless your local codes have made this demand, you can add as many outlets as you want to your microwave’s circuit.
A single outlet makes more sense because you are less likely to overwhelm the circuit, especially if you have other people in the house that are unaware of your desire to keep the other outlets free while the microwave is running.
But you can apply tape to all those other outlets. You can also label them. This will keep people from using them when the microwave is running.
Any circuit can act as a dedicated circuit if it doesn’t have any other items connected to it.