What Is a Dedicated Circuit (Super Simple Explanation)

Some appliances, like electric dryers, should be on dedicated circuits as a matter of safety. It’s all well and good to know this, but responsible homeownership means understanding it so that you can make sure that appliances that need a dedicated circuit always have one.

Happily, dedicated circuits are easy to understand!

A dedicated circuit is one that only supplies electricity to one outlet (used for one appliance), one switch, or one hardwired appliance. They exist to ensure safety in the home. They are controlled by dedicated circuit breakers or fuses.

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Defining a Dedicated Circuit

Electricity is supplied to a distribution board in your house. As the name suggests, this then distributes the current throughout the house. It does this via different circuits.

Circuits can run between the board and outlets, switches, and junction boxes for hardwired appliances and devices.

A dedicated circuit is one that supplies electricity to only one switch, hardwired appliance, or outlet. If it leads to an outlet, that outlet can only be used for one appliance or device.

Man switching the switch in an electrical panel

Why Dedicated Circuits Are Necessary

The National Electrical Codes require certain appliances to be placed on dedicated circuits. Beyond this, there are some electrical devices that just logically require their own circuits.

So, whether it’s code-required or plain sensible, here are the reasons why dedicated circuits are required.

High-Power Appliances Can Overload Shared Circuits

Circuits supply a set amount of electricity. It does not depend on what is attached to the circuit. This means that circuits can be overloaded.

We’ve all, at one point, had that one strip plug that was packed with plugs and gave us warnings every time we used too many of the attached appliances at once. Likely, the circuit tripped once or twice.

Thank goodness it did. Otherwise, pushing the limits of our electrical infrastructure would have ended in disaster.

However, a constantly tripping circuit suffers undue stress and is a fire hazard as the wires overheat and may spark right before the breaker flips or the fuse blows.

When you have a high-power appliance on a circuit, then even adding one more device might take the circuit to the point of tripping. The power draw is so high that the demand easily overtakes the supply of electricity.

Not all circuits are rated the same, so this can determine if an appliance requires a dedicated circuit.

For example, if you have a 15 A circuit and a 20 A circuit, a 15 A washer will have to be on a dedicated 15 A circuit, but it can share the 20 A circuit with a couple of lights or other low-power devices.

The following appliances may require a dedicated circuit, depending on the size of the circuit:

Gas dryers
Microwaves
Water heaters
Heaters
Air Conditioners
Garbage disposal
Airfryers/deep fryers
Ovens
Water and sump pumps

However, there are other appliances that will almost always be too large to share any circuit. A really good example is an electric dryer, which has an average current requirement of 30 A.

Security Equipment Must Always Be Functional

Security and alarm systems should be on a dedicated circuit. If they are on a circuit that keeps tripping, the security company will be constantly notified of a power outage.

This could become a nuisance to them and a waste of resources, especially if they keep sending someone over to check your property.

Home security systems have a built-in battery to keep the alarm running during an outage. However, the battery only lasts so long. If you are out or asleep, and the alarm trips due to an overloaded circuit, the battery may die, and your home will no longer be protected.

Smoke alarms, it should be noted, are better to have wired into your lighting circuit. Some states even require the smoke alarm to be wired through a home’s permanent primary wiring. It is best to check your local legislation.

Many electricians and fire inspectors notice home smoke alarms on their own circuit have been turned off at the breaker.

This was either by accident (you wouldn’t notice because the circuit is not supplying something that you use regularly) or because the alarm was making an annoying sound, and they wanted to shut it off.

Having the smoke alarm wired into your lighting circuit will prevent this, and you will be reassured your smoke alarm will always be on and working.

Protection Appliances Cannot Risk Being Tripping

According to the National Electrical Codes, any appliance that is important in protecting your home needs to be on a dedicated circuit. This ensures that another appliance does not trip the power supply to your critical appliance.

Sump pumps, for example, need to be on a dedicated circuit so that everything will always be functional. If there is a heavy storm and the sump pump trips, your basement and house are at risk of flooding.

Another essential appliance you may want on a dedicated circuit is your fire alarm.

Again, as with your security system, when the power to the fire alarm trips, it sends a signal to emergency services.

If the fire alarm fails to work during a fire because you were running your dodgy space heater on the same circuit (also a likely culprit for the fire starter), emergency response will be unable to be notified, and no one will come to assist.

Other appliances could include your furnace and water heater. If your furnace and water heater trip, they will be unable to keep your house and bath water heated. No one wants a cold house and definitely not a cold shower.

Modern refrigerators and freezers, although use little electricity, are a good idea to have on a dedicated circuit. This can protect your food and beverages from spoiling due to your freezer or fridge tripping from an overloaded circuit.

What Does a Dedicated Breaker Mean?

A dedicated breaker is the switch for the dedicated circuit that can be found on your distribution board.

It serves to cut off the electrical supply to the only appliance on that circuit in the case of power overload or other potentially risky situations.

Often, the breakers are labeled with the name of the appliance on the dedicated circuit, which can be an indication of which circuits are serving only one appliance. However, there are more reliable methods to determine if a circuit is dedicated or shared.