By Alexandr Godonoaga, Owner & Lead Electrician, Cob Services LLC — Illinois License #26-00032356, ICC-Certified, ComEd-Approved EVSP
I quoted three EV charger jobs last week. I walked away from one of them. The customer didn’t love hearing it, and I felt bad about saying it, but the truth is the truth: their garage wasn’t ready.
Not “ready with some upgrades.” Not “ready if we get creative.” Just not ready. Not at a price that made sense for what they were trying to do.
Most blog posts about EV charger installs tell you the same upbeat story: pick a charger, pick an installer, you’ll be charging by tonight. That story is true for maybe 60% of the homes I look at in Naperville. The other 40% have something going on that needs fixing first, or budgeting around, before a Level 2 charger makes sense. Nobody writes that post because nobody wants to talk a customer out of a sale. I’d rather tell you on day one than have you upset with me on day three, so here’s what I actually see.
If any of the things below describe your garage, your home, or your panel, take a breath before you order a Tesla Wall Connector off Amazon. There’s a good chance the install is going to be more involved — and more expensive — than the $800 quote on the brochure.
Your panel is 100 amps and full
This is the single most common reason I have to slow a job down. It’s also the one customers push back on hardest, because the panel “looks fine.”
Most of Naperville’s housing stock built before 2000 came with 100-amp service. That was plenty for the 1980s. It is not plenty for a modern home with a heat pump, a tankless water heater, an induction range, central AC, and a couple of teenagers running hair dryers at 7 a.m. Add a 48-amp Tesla Wall Connector to that load (which under NEC 625.41 has to be calculated as a continuous load at 125%, so 60 amps of headroom) and the math just doesn’t work.
I run a load calc on every quote. About a third of the time on older homes, the calc comes out at or over the 80% service capacity threshold before the EV charger is even added. That means a panel upgrade has to come first. From 100A to 200A in Naperville runs about $2,500 to $4,000 depending on what ComEd needs to do at the meter. Not a small line item.
The trap: a lot of homes have a 100-amp panel with empty breaker slots. People see empty slots and assume there’s room. There usually isn’t. Empty slots tell you nothing about whether the service feeding the panel can handle another 60 amps of continuous load. The slot count and the load capacity are two different things.
We have a self-assessment guide for whether your Naperville panel can handle an EV charger over on the blog — it walks through the rough calc you can do yourself before calling anyone.
Your garage is detached, and the run is long
Attached garage with the panel right on the other side of the wall? Easiest install I do. 3 hours, charger live by lunch.
Detached garage 80 feet from the house, panel in the basement on the opposite side? Different conversation entirely.
Two things change. First, you’re either trenching for an underground conduit run or going overhead, both of which add real cost. A trench for a long run usually adds $1,200 to $2,500 to the job depending on how much concrete and landscaping is in the way. Second, voltage drop starts to bite. The NEC’s recommended limit for branch circuits is 3% drop. On a 48-amp Level 2 charger, you can stay under that limit on #6 copper out to roughly 150 feet. Past that, you have to upsize to #4 copper, which is more expensive wire and a harder pull through conduit.
If you have a detached garage that already has power running to it — even just for lights and an outlet or two — that existing feeder is almost never sized for an EV charger. A typical detached-garage subpanel was designed for maybe 30 amps total. An EV charger by itself wants 60. The existing feed has to be upgraded to the garage, which means new wire from the main panel, possibly a new subpanel in the garage, and sometimes a new conduit path.
I’m not saying don’t do it. I install EV chargers in detached garages every month. I’m saying budget for the real number, not the brochure number. The real number on a detached-garage install in Naperville is usually $2,500 to $4,500.
Your garage is uninsulated, and you live in Naperville
This one catches people off guard. The charger itself can handle the cold — every Level 2 unit I install is rated to operate well below zero. The wiring isn’t the problem either. The problem is what cold does to everything around the install.
A few things I’ve watched go wrong in unheated Naperville garages over the past few winters:
GFCI breakers tripping at 5 a.m. on the coldest mornings. NEC 625.54 requires GFCI protection on EV charging outlets. GFCIs in cold, damp environments throw nuisance trips. Customer wakes up, car didn’t charge, has to call me.
Romex run through cold attic spaces or against exterior walls degrades faster than wire run in conditioned space. Not a year-one problem. A 10-year problem.
And then there’s the human side: nobody wants to plug in a charging cable when it’s -8°F. The cable is stiff, the connector is icy, and after a few weeks of that you start “forgetting” to plug in. The car doesn’t precondition properly the next morning, range tanks, you get frustrated with the car.
If your garage is uninsulated, I’m not going to tell you to insulate it before installing a charger. That’s not my call. What I will tell you is: pick a hardwired Level 2 charger with a holster mounted at a reasonable height, run the wire in conduit (not Romex) on the cold side of any wall, and plan for a slightly longer install timeline because cold-weather installs take more care.
This is the opposite of the standard sales pitch but it’s reality on a -10°F January morning in Will County.
Your house was built before 1995 and still has its original wiring
Pre-1995 Naperville homes often have aluminum branch wiring, undersized neutrals, or in older cases, cloth-insulated wiring still running through walls. None of that necessarily prevents an EV charger install. The new run from your panel to the garage will be modern copper regardless. But it tells me something about the house, and I want to know it before I quote.
What I’m looking for: signs that the panel itself is overdue for replacement, not just an upgrade. Federal Pacific panels, Zinsco panels, certain old Pushmatic panels — these are documented fire risks even without an EV charger added. Adding 60 amps of continuous load to a panel that should have been replaced 15 years ago is the wrong move. We’d replace the panel as part of the project.
If your home is 30+ years old and the panel still has the original brand and breakers from when it was built, mention it when you call. It changes the quote.
You have solar, a battery, and a generator
This is the modern Naperville garage I see more of every year. Solar on the roof, a Powerwall or Enphase battery in the garage, a Generac on a transfer switch outside. The customer wants the EV charger to “just work” with all of it.
It can. But the install isn’t standard.
The charger has to be wired downstream of the right point in the system so that:
When utility power is out, the charger either pauses or runs at a reduced rate that doesn’t drain your battery in 90 minutes When the generator is running, the charger doesn’t try to pull 48 amps from a generator that can only deliver 30 When the battery is exporting and solar is producing, the charger ideally prioritizes solar before pulling from the grid
This works with the right charger (the Wallbox Pulsar Plus, ChargePoint Home Flex with energy management, or a Tesla Wall Connector paired with a Powerwall Gateway will all handle versions of it). It does not work with the cheapest Amazon unit and a normal install. A customer who buys a $400 charger and expects it to coordinate with their inverter and generator is going to be disappointed.
The install on a fully integrated home like this isn’t $800. It’s usually $1,800 to $3,200, plus whatever the charger itself cost, because of the load management programming and the additional documentation required for the ComEd EV rebate if the customer is going for it.
Your “garage” is actually a carport, a driveway pole, or a parking pad
Outdoor installs are perfectly legal under NEC 625, but they require a few things customers don’t always think about:
A weatherproof, NEMA 3R or 4-rated EVSE — most home Level 2 chargers are rated for outdoor use, but some aren’t. Check before you buy.
A pedestal mount if there’s no wall to attach to. Pedestals add $300–$600 to the install.
A conduit path that’s protected from lawn mowers, snowblowers, and kids on bikes. PVC conduit underground, transitioning to galvanized or rigid metal where it comes up out of the ground.
GFCI protection that won’t nuisance-trip in heavy rain or snow. This means a quality breaker, not the bargain-bin one.
If your “garage” is really a parking pad off your driveway, it’s still doable. It just isn’t the same job as bolting a charger to drywall in an attached garage.
So when does it make sense to wait?
Sometimes the right answer is “fix the underlying issue first, then come back.”
Panel upgrades are a good example. If your panel is at capacity, doing the upgrade as a standalone project can be cheaper than rolling it into the EV install — different permit category, different inspection, sometimes cleaner timing all around. We have a separate post on when to upgrade your electrical panel in Naperville that walks through the warning signs.
Detached garages without any existing power are another. Rather than running a single dedicated EV circuit out there as a one-off, it can make more sense to install a real subpanel — lights, outlets, maybe a 240V circuit for shop tools — and add the EV circuit to that subpanel later. More work up front, less work down the road.
Mid-remodel is the cheapest possible time to add an EV circuit. While walls are open, fishing wire is trivial. After drywall goes back up, every additional run costs more.
And if you don’t actually own an EV yet but you’re “thinking about getting one in the next year or two”? It’s fine to wait. The federal Section 30C tax credit for residential charging expires June 30, 2026, which is a real deadline if you’re going to install in 2026. But if you’re planning for 2027, none of the equipment is going anywhere, and Level 2 hardware prices have been dropping. There’s no urgency to install a charger you won’t use for 18 months.
What a good site walk should tell you
Any installer worth hiring should do a free site walk before quoting. What I’m looking at when I come out:
Where the car parks and where the charger needs to mount. Cable lengths matter. A 25-foot cable on a 48A charger reaches most parking spots. An 18-foot cable doesn’t always.
Your panel — make, model, age, current breaker layout, and a load calc. I take photos and run the numbers in my truck before I quote.
The path from the panel to the install location. How many walls, what’s behind them, where the studs are, where the existing receptacles and switches are.
Whether the garage is conditioned or not, and what the run distance actually is.
Your service entrance — meter, mast, weather head — in case ComEd has to be involved for a meter pull.
Any solar, battery, or generator equipment that’s already in place.
If an installer quotes you over the phone with no site walk, you’re either getting a lowball that will go up on install day or a high-side bid built to cover unknowns. Neither is what you want.
If you want a realistic look at whether your specific Naperville garage is ready — before you spend a dollar — I do free site walks across Naperville, Aurora, Plainfield, Lisle, Bolingbrook, Downers Grove, and the rest of DuPage and Will County. The EV charger installation page has the request form, or call (630) 427-5923. Same crew on every install, same lead electrician from quote through final inspection.
Quick FAQ
Can I just plug a Level 1 charger into a regular outlet and skip all this?
For some drivers, yes. A standard 120V outlet adds about 4 miles of range per hour. If you drive less than 30 miles a day and have 10+ hours overnight, Level 1 is sometimes enough. For most modern EVs and most commute patterns, it isn’t.
How do I know if my panel is 100 amps or 200 amps?
Look at the main breaker at the top of your panel. The number stamped on it (100, 125, 150, 200) is your service size. If it says 100 and the panel is more than 20 years old, plan for a possible upgrade as part of any EV install.
What’s the actual code rule on continuous load sizing?
NEC Article 625 classifies EV charging as a continuous load. Branch circuits and breakers must be sized at 125% of the EVSE’s maximum draw. A 48-amp Tesla Wall Connector requires a 60-amp breaker and #6 copper minimum. A 40-amp charger requires a 50-amp breaker. The full code text is available through NFPA’s free public access to NFPA 70.
Will my homeowners insurance care about an EV charger install?
Most won’t, as long as it’s permitted and inspected. Some carriers have started asking about charger location and brand. Worth a quick call to your agent before install, especially if your charger goes outdoors or in a detached structure.
Can I install the charger myself and have it inspected?
In Illinois, EV charger installs over 30 amps require a permit pulled by a licensed electrical contractor in Naperville. DIY installs typically don’t pass inspection and won’t qualify for ComEd rebates or federal tax credits.
Alexandr Godonoaga is the owner and lead electrician at Cob Services LLC, an Illinois-licensed (#26-00032356), ICC-certified, ComEd-approved EVSP serving Naperville and the western suburbs. He has personally led EV charger installations across DuPage and Will County since 2021. Call (630) 427-5923 for a free site walk.