The calculation comes before the charger

A home charger is a continuous load, which means your service either has room for it or does not. So we add it up first: floor area, heating and cooling, range, dryer, water heater, well pump if there is one, then the charger on top. The number that falls out defines the whole job, and it is why nobody should quote this over the phone. Two houses that look identical can land on opposite sides of the line because one has a gas range.

What a Level 2 circuit really is

Two hundred forty volts on a dedicated circuit with nothing else sharing it. The breaker and the conductors are sized to the charger's continuous rating plus the headroom the code requires, so a charger has to sit on a circuit rated meaningfully above what it draws. None of that bends to fit a spare space in your panel.

Reading the panel honestly

Two empty slots is not capacity. Capacity is what the service can carry; the panel is only where the breakers live. Plenty of houses have room in the box and nothing left in the service, and the reverse turns up too.

When a subpanel answers it

If the service has capacity and the panel is just physically full, a subpanel is the clean fix and it is short work. It also leaves room for the next thing, usually a second charger or a shop circuit.

If the calculation says the service is short, a subpanel fixes nothing. That is a service change, and a service change does not run on our calendar alone: ComEd has to drop and reconnect the service and the city has to inspect it.

Hardwired or on a receptacle

Hardwired is cleaner and it is what we suggest for a unit that is staying where it is put. No plug, no receptacle to heat up, cable straight into the charger. In an unheated garage or outdoors it is also the more durable of the two.

A receptacle earns its place if you expect to swap units, or you want to take the charger with you when you move. The trade is a connection that can work loose, and on a circuit running near its rating for six hours a night that is the connection that warms up.

Getting power out to a detached garage

An attached garage is usually a short run through the adjoining wall and the labor is small. Detached is a different animal, because a feeder has to physically get out there.

Out in the newer subdivisions that feeder normally goes underground, and underground is a dig: locates called before a shovel moves, burial depth and conduit that satisfy the inspector, and your lawn open for a day. The electrical half is the easy half.

Charging through a Boone County winter

Cold costs you range and it slows the charge. A pack below freezing accepts power more slowly than a warm one, and some of what you draw overnight warms the battery instead of filling it. That is chemistry, not a fault to chase, which is why people who charged happily in October call in January.

What helps: a circuit sized correctly rather than barely, a unit mounted where you can work the connector with gloves on, and preconditioning the car on shore power rather than off the battery. An undersized circuit is at its worst in the cold.

Where the unit lands on the wall

Mounting height, which side of the car the port sits on, how far the cable genuinely reaches, and whether you still want to walk past the car with the cable hung up. We settle that standing in the garage with you, because it is the part you live with daily and it costs nothing to get right before the cable is run. Outdoors, the unit and its enclosure have to be rated for it, with a disconnect where one is called for.

The permit and what it leaves behind

A new 240 volt circuit is permitted work. We file it, meet the inspector and hand you the paperwork at the end. People skip this on a charger more than on any other job, usually because the unit arrived in a box with a plug on it and felt like an appliance.

Planning for the second car

Most households that install one charger end up with a second car inside a few years, and the cheap moment to allow for that is while the wall is already open. A larger feeder out to the garage, or space left in a subpanel, is a small addition now and a whole second job later.