Electrical
EV charger install questions to answer before you quote the job
Before quoting a home EV charger, get a photo of the open panel door showing the main breaker and open spaces, ask how far the parking spot is from the panel, and ask which charger they bought and whether it goes inside or out. Those answers tell you if it's an easy afternoon or a load calculation, a long run and a possible service upgrade.
Someone just brought home an EV and wants a price on a charger. They expect a number on the phone, the way they'd get one for a ceiling fan. Don't guess. This job can be an easy afternoon with a short run in the garage, or a load calculation, a long trench and a service upgrade. Five minutes of the right questions tells you which.
Start with the panel
Ask for a photo of the panel with the door open. You want to see the main breaker, the labels if there are any, and whether there are open spaces for a two-pole breaker. A second photo of the sticker inside the door and one of the meter outside help too.
Safety first: Be specific when you ask. You want the panel door opened, not the inner cover removed. Tell the customer not to unscrew anything or touch the breakers, and to just take the picture and close it.
The photo answers the biggest question on the job: will it fit? Plenty of older homes still have a hundred amp service, and a lot of Level 2 chargers want a 40 to 60 amp circuit. Add an electric range, a dryer, a heat pump or a hot tub, and that hundred amps gets crowded fast. The photo also shows you panel brands and conditions you'd rather know about before you're standing in front of it. If something in the picture worries you, panel warning signs covers what to look for.
If the panel is tight: calc, manage or upgrade
A crowded panel doesn't automatically mean a service upgrade. There are usually three paths, and the photo plus a few questions tell you which to price:
- Load calculation. Run the numbers on the existing service. Sometimes there's more room than the breaker count suggests.
- Turn the charger down or manage the load. Many chargers let the installer set a lower maximum current, and load management devices can share capacity with other big loads. A lower setting often still charges the car overnight.
- Service or panel upgrade. When the calculation doesn't work and managing the load isn't enough. That's a different quote, a different timeline, and usually the utility gets involved. More on pricing it is in how to quote a panel upgrade.
Tell the customer up front that you'll know which path after you see the panel. It keeps the first number from turning into a fight.
Sizing the circuit to the charger
EV charging is treated as a continuous load, so the circuit has to be sized to at least 125 percent of the charger's continuous current. The charger's install manual gives the rating and the breaker it expects. Check your local code and which code edition your area has adopted.
Example numbers
A charger set to draw 48 amps continuous needs a 60 amp circuit (48 x 1.25 = 60). The same charger dialed down to 32 amps fits on a 40 amp circuit (32 x 1.25 = 40). On a crowded hundred amp service, that difference can decide whether you're doing a simple install or quoting an upgrade.
How far is the car from the panel?
Next question: where does the car park, and where's the panel? Twenty feet along a garage wall and eighty feet across the driveway are completely different days. Distance drives wire size, material cost, labor and whether you're drilling, fishing, surface mounting or digging.
Ask for a photo of the spot where the charger will go, and ask what's between it and the panel: a finished basement ceiling, an attic, a crawlspace, a concrete driveway, a patio. A panel on the far side of the house from the garage changes the job more than almost anything else on this list.
Which charger, and does it go inside or out?
| Question | Why it matters |
|---|---|
| Which charger did you buy, or are you buying? | Its specs set the circuit size, and some models have adjustable current settings |
| Hardwired or plug-in? | Hardwired needs a disconnect plan per the manual and local code; plug-in needs a heavy-duty 240-volt receptacle |
| Inside the garage or outside? | Outdoor installs need rated equipment and fittings, and the location affects protection requirements |
| One EV or two coming? | A second car later may change what you'd install now |
If they chose a plug-in unit, use a receptacle rated for the continuous load, not the cheapest one on the shelf. Plenty of electricians prefer to hardwire when the charger allows it. Also ask whether they're applying for a utility rebate, because some programs have rules about equipment and installation you'll want to know before you quote.
Mention the permit on the call
Most EV charger installs will need a permit and an inspection. Requirements vary by city and county, so check yours. Say it on the phone so the customer isn't surprised by the fee or the inspection visit, and so they understand why your quote is higher than the handyman who told them "no permit needed." Building the inspection into your calendar is covered in scheduling permits and inspections.
Your five-minute intake list
Keep this by the phone or saved on it:
- Panel photo, door open, plus the door sticker and the meter.
- What big electric appliances are in the house? Range, dryer, water heater, heat pump, hot tub.
- Where does the car park, and how far is that from the panel? Photo of the spot.
- What's in between? Finished walls, attic, crawlspace, concrete.
- Which charger, hardwired or plug-in, inside or outside, and any rebate program.
- Heads up on the permit and the inspection visit.
Five minutes on the phone, and you show up with the right wire, the right breaker and a price that holds.
Common questions
What if the customer hasn't bought a charger yet?
Ask what car they have and how far they drive on a typical day. Many drivers do fine with a charger set well below its maximum, which can avoid a bigger circuit or a service upgrade. Suggest they check whether their utility offers a rebate before buying, since some programs only cover certain models or require specific installation steps.
Can a customer just use a regular outlet instead?
Many EVs come with a cord that plugs into a standard 120-volt outlet, and for short daily commutes that can be enough. It charges slowly, though, and the outlet should be on a circuit in good shape without other heavy loads. If they plan to rely on it, it's worth having an electrician check that circuit first.
Does a charger in a detached garage change the job?
Usually a lot. You may be looking at a feeder to a subpanel, a trench or an overhead run, and extra permit and inspection steps. Ask whether the garage already has power, how big that feed is, and what's between the house and the garage, like a driveway, patio or landscaping.
Why do some plug-in chargers keep tripping the breaker?
Newer code editions require GFCI protection on many 240-volt receptacles in garages and outdoors, and some chargers have their own ground fault protection that can conflict with a GFCI breaker. The fix depends on the charger and your local code, which is one reason many electricians prefer to hardwire when the charger allows it.