Dryer Breaker Sizing Guide (Tips to Be Code Compliant)

Although dryers are an appliance that makes our lives so much easier, their tendency to cause fires in extreme situations is more than a bit frightening. This is where circuit breakers come in to mitigate this risk.

The rating of a circuit breaker is detailed in the National Electrical Code (NEC) but it is important to note that both an underrated breaker and an overrated breaker can either be hazardous or extremely frustrating. For this reason, circuit breakers must be sized correctly.

According to the NEC, a circuit breaker for a dryer should be rated at 125% of the dryers ampere rating. Using an overrated circuit breaker is dangerous as too much current can flow through the circuit before it cuts off. Using an underrated circuit breaker will result in the dryer tripping all the time.

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Sizing a Circuit Breaker According to Code

According to Section 210.20A of the NEC:

“Where a branch circuit supplies continuous loads or any combination of continuous and noncontinuous loads, the rating of the overcurrent device shall not be less than the noncontinuous load plus 125% of the continuous load.”

This section of the code specifically applies to dryers and appliances with a similar demand for power.

This NEC regulation basically means that the current need of the appliance must be paired with a circuit breaker with 125% of that amperage. For example, a dryer with a current need of 22 amperes requires a circuit breaker of at least 27.5 amperes.

Tips for Being Compliant

For the most part, a breaker size of 30 amperes should work for your dryer, but this might not always be the case.
Research the amperage of your dryer, it is likely to vary with the type of dryer.
For example: gas dryers use significant less electricity.
If A is the amperage of your dryer, multiply that by 1.25 to get B, the required minimum amperage for your circuit breaker. (A x 1.25 = B)
Time delay fuses are also required by the NEC to allow for a temporary current surge that doesn’t go above the fuse’s current rating.
As well as the dryer’s breaker being rated at 125% of the dryer’s amperage, the dryer must also be plugged in with a 4-prong, grounded wire to prevent a shock or fire.

Dryer Breaker Sizing Table

Type of Dryer	Voltage Rating	Required Circuit Breaker Size
Natural Gas Dryer	110V	15/20A
Natural Gas Dryer	120V	15/20A
Vented Electric Dryer	208V	30A
Vented Electric Dryer	240V	30A
Condensing Dryer	220V	30A
Condensing Dryer	240V	30A
Heat-Pump Dryer	220V	30A
Heat-Pump Dryer	240V	30A
Steam Dryer	110V	15A
Steam Dryer	120V	15A
Washer/Dryer Combo	220V	30A
Washer/Dryer Combo	240V	30A
LP Dryer	110V	15A
LP Dryer	120V	15A
Compact Washer/Dryer Combo	110V	15A
Compact Washer/Dryer Combo	120V	15A
Compact Electric Dryer	110V	15A
Compact Electric Dryer	120V	15A

The Importance of Circuit Breakers for Dryers

Dryers, like most heat-generating appliances, require a large amount of electrical flow to keep them operating. Because of this, dryers are at a higher risk of causing electrical fires through overloading their circuit.

illustration of circuit breaker in breaker box

This is where a circuit breaker becomes especially important. Circuit breakers monitor the current flowing through the circuit. If the current levels reach a number that is unsafe, the circuit breaker will cut off all power to that circuit.

You will be able to tell if your breaker has tripped if the switch for that particular circuit has been switched off. All devices connected to this circuit will also lose power.

To be able to tell what amperage your circuit breaker will cut the power at, consult the label on your circuit breaker. Be sure to have a higher amperage circuit breaker for your dryer because a 20-ampere circuit breaker will not allow for the required current to power your dryer.

If the circuit used for your dryer was not protected by a circuit breaker, an electrical fire may occur if too much current is running from the circuit to the dryer. Not only is this a danger to your home and its appliances, but your life would also be in danger.

Can I Use a 50 Amp Breaker for a 30 Amp Dryer

Although it may seem like any rating of breaker above what is needed would allow for safe usage of power by a dryer, this is not necessarily the case.

If the rating of a breaker is too high, when the current reaches levels that are too high for the appliance, the breaker will not cut off the power supply. It would instead take 50 amperes of current in order for the circuit breaker to cut the power.

The Danger of Using Overrated Breakers

When your dryer requires 30 amps of electricity, any current above 30 amps is likely to overheat the wires. With a breaker at 50 amps, it will take an electric flow of 50 amps for the breaker to trip and cut off power. At this point, it is likely to be too late.

When wires overheat, they are likely to melt and burn. Not only does this damage the wiring to your appliance, but it can also start fires.

Electrical fires are even more dangerous than normal fires because they cannot be put out with water because electricity is conducted through water. In fact, water makes the situation worse and will cause the fire to spread.

For this reason, electrical fires must be put out with either a fire extinguisher with a “C” on its label, baking soda, or with a blanket (to eliminate the source of oxygen).

Although damage from overheated wires is inevitable, it is possible to prevent an electrical fire from these wires.

If you are able to spot the signs of overheating wires, you can identify the breaker they are assigned to and turn it off.

The signs of burning wires include:

The smell of smoke as well as a burning smell.
Electrical appliances in a certain area flickering or not working properly.
The sight of smoke at an outlet.
Several outlets in a room not working properly.

When you’ve identified the signs and the appliance whose wires are burnt, it is important to also identify which breaker this appliance is connected to. When this breaker can be identified, it can be turned off manually.

If you are not able to turn the breaker off in time and the circuit breaker also doesn’t do its job, an electrical fire may start and cause damage to your home and possibly injure the residents.

Problems With Underrated Breakers for Dryers

While overrated breakers for dryers can be a large problem of safety, too low of amperage for a circuit breaker is a problem as well.

This is because the breaker will continuously trip if the rating is too low.

For example, let’s say your dryer uses about 30 amperes of current but your circuit breaker cuts off the power at 20 amperes of current.

This means that as soon as the current through the breaker is at 20 amperes, the breaker will trip and your dryer will cease to function. This will happen every time you try to use your dryer since it is supposed to use more than 20 amperes as it dries.

Each time you try to run your dryer, the power will be shut off and your clothes will remain wet. If you are busy and not monitoring your dryer, your clothes are likely to sit in the dryer, still wet, and may begin to smell musty if left long enough.

The first thought you may have is that the dryer is the problem and not the circuit breaker. You may check the connections and wonder why the dryer has no power even though it is plugged in correctly.

You may even wonder if your dryer is broken, which is a large setback since dryers are certainly not cheap.

Hopefully, though, before you jump to the worst conclusion, you check your breaker box and see that the breaker has tripped.

Even if you continuously turn the breaker back on after each trip, though, the cycle is likely to be halted and your clothes will still not be dry after all of this effort.

Although an underrated breaker is not much of a safety concern, it is still a source of frustration and will likely lead to laundry becoming difficult, if not impossible, to do.

Another reason why your dryer may be tripping is if you’re using it with a low voltage extension lead.

How Do I Know if My Breaker Is the Correct Size?

As mentioned above, the circuit breaker of your dryer must be at least 125% of the amperage of your dryer. That being said, in order to know the correct size of breaker for your dryer, you must know the amperage of your dryer first.

In most cases, your dryer will list its amperage as well as its voltage on a plate or sticker somewhere on the machine. It is often located at the front or back of the dryer. This information should also be somewhere in your dryer’s manual.

If this plate or sticker is nowhere to be found, if you research the make and model of your dryer, you are likely to find its amperage.

Although the internet is often a great resource, this might not work either.

The chart above details the type of dryer, its common voltages, as well as the required amperage of the circuit breaker are given above. These numbers may vary by brand, though, so it is wise to look up brand-specific information.

One way to find current precisely is to do some math. Wattage divided by voltage is equal to current (amperage), so if these values are known, you can find the exact amperage your dryer requires.

Once you have found your dryer’s amperage, you must multiply this by 1.25. The value given does not have to be followed strictly, but a value around that would be ideal.

For example, 22A x 1.25 is equal to 27.5. In this situation, though, a 30-ampere circuit breaker should be fine.

It is important, though, not to stray too far from the suggested circuit breaker rating. As gone over above, too low can result in a non-functioning dryer and too high can result in fires.

Is It Easy to Replace the Breaker for a Dryer?

Replacing the breaker for your dryer, whether your breaker is too high, too low, or not functioning properly, is a fairly simple process but one whose steps must be followed carefully for your own safety.

It is important to note that breaker replacements are not universal, so stick to the brand of your service panel to ensure that your circuit breaker can work at its best.

Moreover, I do recommend hiring a professional for anything electrical-related because of how dangerous it can be if you do it incorrectly.

The items needed for this process include:

Screwdriver
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Electrical Tester
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First, the main breaker must be shut off. The switch for this is found at the top of the service panel.

Then, the service panel must be opened for you to gain access to the wires and circuit breakers.

To ensure that there is no electricity running through the service panel, use your electrical tester to touch the screw holding in a breaker and the metal surface of the service panel. If no wattage is detected, the repair should be safe.

Next, unscrew the two screws securing the breaker and pull the red and black wires from under the screws. You can then remove the breaker.

You can then place the new breaker into the service panel. Before screwing it in, make sure that the red and black wires are under the two screws and held securely by the breaker. You can then tighten these screws.

Once you are done, you can close the service panel cover and turn the main breaker back on.