I worked at a coffee shop for four years, and the cramped kitchen housed outlets that supplied energy to the oven and panini press. Turns out, those outlets were on a branched circuit with a lower power rating than the combined appliances. We paid the price when the fuse blew during a morning rush.
Not all large appliances are plugged into outlets with dedicated circuits, so it can be difficult to find dedicated circuit outlets without tearing open walls and looking at the electrical wiring. In the article below, we’ve given an easy, non-invasive way to find out if an outlet is on a dedicated circuit.
Large appliances such as ovens and dryers, as well as important equipment like sump pumps and alarm systems, require a dedicated circuit. The easiest way to determine if an outlet is on a dedicated circuit is to test the outlets. To do so, flip individual breakers and see what outlets turn off.
What Does the Outlet Serve?
Knowing what an outlet serves is a great hint as to whether or not it is on a dedicated circuit, as some appliances are required to have their own due to the amount of electricity they require to function.
Large appliances are more likely to be connected to an outlet on a dedicated circuit because their power requirements may exceed the capabilities of a branch circuit.
Power ratings can be found on large appliances themselves or in their manuals. The rating of a circuit must be greater than that of the appliance.
However, it cannot be generalized that all large appliances are plugged into outlets on a dedicated circuit. For example, a gas dryer and a washer can typically share a 240 V outlet and a 20 A circuit.
On the other hand, an electric dryer needs its own 240 V outlet and its own circuit, typically a higher-rated circuit than normal.
The following kitchen appliances also commonly require outlets on dedicated circuits:
- Garbage disposals
- Electric ranges
The following appliances may also pull so much power that they require an outlet on a dedicated circuit:
- Water heaters
- Chest freezers
- Air conditioning units
- Garage door openers
- Hot tubs/saunas
You may consider using an outlet on a dedicated circuit for these appliances to avoid the possibility of overloading the circuit and tripping the circuit breaker. And while some electricians consider it best practice to do so, it is not always required.
There are also some appliances and devices that need a dedicated circuit as a matter of safety and protection. You can be sure that the items discussed below are using an outlet on a dedicated circuit.
Septic systems require not only one but two outlets, each on a dedicated circuit. One is for the septic pump, and one is for the high-level alarm system.
If the pump trips the breaker and the alarm is on the same circuit, the alarm will not go off.
This requirement is specifically included in state codes, such as Tennessee’s “Regulations to Govern Subsurface Sewage Disposal Systems”, found in Rule 1200-1-6-.14.
Although not stated in building codes, plumbers almost universally recommend installing sump pumps with an outlet on a dedicated circuit.
On a branched circuit, something else could flip the breaker and prevent your sump pump from moving water away from your basement.
The International Residential Code (IRC) also requires that outlets installed to charge electric vehicles be connected to a dedicated circuit in Section E3702.13.
Be sure to check your local electrical codes to make sure you comply with any additional guidelines.
Look at the Fusebox/Circuit Breaker Labels
Instead of focusing on the items using the outlets, you can go to the fusebox/circuit breaker to find more information on whether the outlet is a dedicated circuit.
Your electrical panel or fuse box should have labeled circuits for your convenience and safety. If a circuit is labeled with one appliance, it most likely is a dedicated circuit.
Often, circuit breakers and fuse boxes will be labeled according to what they serve. Any fuse/breaker labeled for a specific appliance is likely to serve only one outlet.
However, don’t simply rely on circuit breaker labels to determine if an outlet is on a dedicated circuit. Circuits may be incorrectly labeled and in some cases are not labeled at all despite NFPA 70 requirements.
Since electrical work can be done by homeowners, you can’t always trust that previous owners know all NFPA regulations, and depending on how old the building and electrical system is, NFPA regulations may have changed since the original installation.
Test the Outlets
You can get an idea of whether an outlet is on a dedicated circuit based on what it serves, but the most surefire way to know is to test the outlet yourself.
1. Turn on All the Lights and Hardwired Appliances
To begin this test, switch on all the lights and hardwired appliances.
For example, if you are trying to figure out if an outlet in your kitchen is on a dedicated circuit, turn on all lights, the range hood, and oven.
It’s important to turn on these large appliances because they may share a circuit with an outlet that would otherwise appear to have its own circuit.
2. Plug an Appliance Into Every Outlet
Next, find a suitable appliance to plug into every outlet.
Make sure to use small items so as not to overload any of the circuits. Since you are testing to see if an outlet is on a dedicated circuit, overloading any one of the circuits and causing the breaker to flip will impede this process.
Something like a small table lamp or a nightlight with a manual on/off switch are good options for simple small appliances. The light emitted from them also easily indicates whether or not the circuit is on.
You may be tempted to use Christmas lights as they also can readily show if an outlet is providing electricity, but be warned that some, especially non-LED types, may cause the breaker to flip.
Turn all the appliances on.
3. Remove Fuses or Flip Breakers One at a Time
This next step is easier with more than one pair of hands, so enlist your friends and family to help you. One person can flip the breakers while the other helps record what outlets stop supplying electricity.
Turn off each circuit one at a time and see what appliances, lights, etc., went off. In a fuse box, this requires that you remove the fuse. In a breaker panel, manually flip a breaker to turn off one circuit.
Keep a record of which ones turn off so that you can return to the information later as well. It may be useful to create a diagram or map of the circuits for future reference.
Turn all the circuits back on before testing the next one.