By Alexandr Godonoaga, Owner and CEO, Cob Services LLC. Naperville, IL. Illinois Electrical Contractor License #26-00032356. Published April 10, 2026. Last reviewed and updated September 5, 2026.
We get some version of this call about twice a week, and it almost always opens the same way: “My breaker keeps tripping when the microwave runs. Is that a big deal?”
Usually yes. And the fix is usually a dedicated circuit. But “you need a dedicated circuit” is advice that’s correct so often it has stopped carrying much information. So here is the version we’d give you standing at your panel: what a dedicated circuit actually is, what the code enforced in Naperville requires, what it doesn’t require but we’d still recommend, and the specific things we find in homes around DuPage County that tell us a circuit is overloaded before the breaker ever trips.
If you already know you need one and just want it installed, our dedicated circuit installation page covers the process. This post is for homeowners still working out whether they have a problem.
What a dedicated circuit actually is
A dedicated circuit is a single wire running from one breaker in your panel to one outlet or appliance, with nothing else attached to it.
That’s the whole idea. The “dedicated” part isn’t about special wire. It’s about one breaker being responsible for one thing. A standard circuit in an older Naperville home might carry six outlets, three light fixtures, and the bathroom fan on a single 15 amps. A dedicated circuit has one job, so when that appliance pulls power, nothing else in the house notices.
Three reasons the code cares
Naperville enforces the 2023 National Electrical Code, and the City requires an electrical permit before any electrical work inside city limits, performed by a state-licensed contractor who is also registered with the City. Knowing why the code asks for dedicated circuits matters, because those same reasons apply in situations the code never mentions.
Sustained load and heat. A 15-amp circuit carries 15 amps continuously without overheating. A microwave pulling 12 amps plus a coffee maker pulling 9 amps on the same circuit does not. The breaker is supposed to trip before the wire heats up, but breakers age, and old ones fail closed more often than homeowners expect. A dedicated circuit takes the arithmetic out of it.
Voltage drop. When a refrigerator compressor or an AC unit starts, it pulls a brief surge of three to five times its running amperage. On a shared circuit that surge drops the voltage across everything else on the line. It’s why your kitchen lights dim when the fridge cycles. Repeated over years, that shortens the life of motors and electronics.
Warranty language. This one catches people. LG, Samsung, GE, and Bosch all specify a dedicated circuit in their installation manuals for certain appliances. If a fridge fails and the warranty inspector finds it sharing a circuit with the dishwasher, the claim can be denied. We watched that happen twice last year, both times in homes off Ogden Avenue.
The full standard lives with the National Fire Protection Association as NFPA 70, which is the document every U.S. jurisdiction adopts in some form.
What the code requires
These are not judgment calls. Under the code Naperville enforces, each of these gets its own circuit:
- Refrigerator, 20-amp
- Dishwasher, 20-amp
- Built-in microwave, 20-amp
- Garbage disposal, 20-amp
- Electric range or cooktop, 40 or 50-amp at 240 volts
- Electric dryer, 30-amp at 240 volts
- Electric water heater, 30-amp at 240 volts
- Central air conditioning, 30 to 50-amp at 240 volts
- Sump pump, 15 or 20-amp (this one matters more in Illinois than almost anywhere else, and I’ll come back to it)
- Bathroom receptacles, at least one 20-amp circuit serving bathrooms only
- Laundry receptacles, 20-amp
- EV charger, 30 to 60-amp at 240 volts, required by the code and by every charger manufacturer
If your house was built or fully rewired after roughly 2008, most of these are probably already in place. If it went up before 1990, the kitchen circuits usually aren’t, and the laundry circuit is often shared.
What the code doesn’t require, but we’d still do
This is where the calls get more interesting. Four from this year:
A home office running three monitors, a desktop, and a space heater. No code requirement anywhere for an office. But that load sat around 14 amps on a 15-amp circuit and tripped the breaker every cold morning. We ran a 20-amp dedicated line.
A window AC unit in a finished basement bedroom. Not required. The homeowner had run it off a power strip for two summers, and the strip was discolored and warm to the touch when we arrived. Window units pull hard on startup and belong on their own circuit.
An aquarium with heaters and a pump on a timer. Niche, but the homeowner had lost fish twice after a vacuum cleaner tripped the shared breaker. Dedicated circuit, problem gone.
A garage freezer. Same reasoning as the fridge. If the breaker trips while you’re out of town, you come home to a defrosted side of beef.
The pattern we actually use: anything that runs continuously, anything you can’t afford to have shut off without warning, and anything drawing more than half a circuit’s rated amperage. None of that is in the code book. It’s still the right call.
What we find in homes around Naperville
Most of what we see is shaped by the local housing stock, so this section is specific to Naperville, Aurora, Lisle, Plainfield, and the surrounding towns.
Sump pumps sharing a circuit. This is the one that keeps me up. Plenty of homes built before the mid-90s in the older Naperville neighborhoods have the sump pump tied to basement receptacles. A kid plugs a space heater into the rec room during a storm, the breaker trips, and the sump stops. We replaced two pumps this spring that burned out trying to catch up after exactly that. If your sump shares a circuit with anything at all, fix that before you fix anything else.
Federal Pacific and Zinsco panels. A surprising number of homes north of Ogden Avenue still have them. These panels have documented problems with breakers that fail to trip. We’ll add a circuit to one if you ask, but we’ll tell you first that the panel is the larger problem. Our electrical panel upgrade page explains which brands need replacing and why.
Knob-and-tube remnants. Some 1920s houses in the historic district still have isolated knob-and-tube runs feeding upstairs bedrooms. You cannot hang modern dedicated loads off knob-and-tube. When we find it, the conversation turns toward whole-house rewiring or at minimum replacing the affected runs.
Two-refrigerator households. Common in the larger homes in south Naperville and Plainfield. Beverage fridge in the basement, main fridge upstairs, one dedicated circuit each. If an electrician tells you sharing is fine, check the manufacturer’s spec sheet before you agree.
EV charger retrofits. The fastest-growing reason we get called. A Level 2 charger in the garage needs its own 240-volt circuit, no exceptions, and it needs a permit. Details are on our EV charger installation page.
How to check your own panel in ten minutes
Open the panel door and read the labels. A breaker labeled with one word, fridge, dryer, microwave, is a dedicated circuit. A breaker labeled kitchen or upstairs, or carrying no label at all, almost certainly isn’t, no matter what’s plugged into it.
For an unlabeled panel, flip one breaker off and walk the house. Whatever loses power is on that circuit. If one appliance goes dark, it’s dedicated. If half a floor goes quiet, it’s shared.
While you’re there, put the back of your hand near the breakers. Warm breakers are running close to capacity. That’s a warning, not yet a failure, and it’s the best time to call someone.
What a dedicated circuit won’t fix
Adding a circuit solves overload on that circuit. It does nothing for a panel that’s out of slots, an undersized service coming in from the street, or deteriorating wiring inside the walls. If you’re on a 100-amp panel and you’ve added an EV, a hot tub, and central air since 1995, you may be at capacity regardless of how the circuits are arranged. Finding out requires a load calculation, which is the first thing we run on any wiring update or service call.
If you smell burning plastic, see scorch marks around an outlet, or hear buzzing from the panel, stop reading and call. Daytime, (630) 427-5923. After hours, our emergency electrical service line is staffed.
Frequently asked questions
Does a refrigerator really need its own circuit? Yes, and for two separate reasons. The code calls for it, and most major manufacturers require it in writing as a warranty condition. A shared fridge circuit is one of the most common things we correct in kitchens built before 1990.
Do I need a permit to add a dedicated circuit in Naperville? Yes. The City requires an electrical permit before any electrical work begins, and the work has to be done by a state-licensed electrical contractor registered with the City of Naperville. Permits go through the City’s Civic Access portal. We pull them for you as part of the job.
Can I add a dedicated circuit myself? Legally, in Naperville, no. Practically, adding a breaker means working inside an energized panel, and the failure modes there are severe. It’s also the kind of undocumented work that surfaces during a home inspection when you sell.
How much does a dedicated circuit cost? It depends on three things: the distance from your panel to the appliance, whether the run is through finished walls or open basement joists, and whether your panel has an open slot. A short basement run and a full panel needing a subpanel are very different jobs. We quote in writing after we look, never over the phone.
What if my panel is full? You have two options, a subpanel or a service upgrade, and which one is right comes down to your total load. A load calculation answers it in about half an hour.
How long does the installation take? Most single-circuit jobs are a half day. Runs through finished walls, or anything that turns up knob-and-tube along the way, take longer.
The short version
Add a dedicated circuit when the code requires it (kitchen appliances, dryer, water heater, AC, EV charger, sump pump), when your appliance manufacturer requires it for warranty coverage, when a load draws more than half the circuit’s amperage continuously, when you can’t afford an unexpected shutoff, or when the breaker is already tripping.
You don’t need one when a circuit trips because of a one-time overload, like a hair dryer plugged in alongside a space heater. That’s a habit to change, not wiring to replace.
If you’re in Naperville, Aurora, Lisle, Plainfield, Bolingbrook, Downers Grove, Hinsdale, Burr Ridge, La Grange, or elsewhere in DuPage or Will County and you’d like someone to look at the panel before recommending anything, request a service visit or call (630) 427-5923. We’ll run a load calculation, walk you through what’s safe to add, pull the permit, and quote in writing before any work starts.
About the author. Alexandr Godonoaga is the owner of Cob Services LLC and holds Illinois Electrical Contractor License #26-00032356. He has worked on residential and commercial electrical systems in Naperville and the western suburbs for over a decade. Cob Services is licensed, bonded, insured, and registered with the City of Naperville.
Cob Services LLC 2020 Calamos Ct Suite 200, Naperville, IL 60563 (630) 427-5923 Monday through Friday, 9:00 AM to 5:00 PM