Putting an EV charger in a detached garage: what the run really costs

Drive any back road in Calvert County and you will see the layout: a house on an acre or three, and the garage or pole barn sitting thirty, fifty, sometimes a hundred feet away from it. When somebody with that setup asks what a Level 2 charger costs, the honest answer is that the standard numbers do not apply. The charger itself is the cheap part. Getting a 240V circuit across the yard is the job.

Here is how we price a detached garage install, what actually drives the number, and a few things about digging in this county that are worth knowing before anyone puts a shovel in the ground.

Distance is the whole ballgame

A Level 2 charger usually wants a 40 or 50 amp circuit at 240 volts. In an attached garage, that circuit might be ten feet of wire from the panel to the wall. Across a yard, every foot costs money twice: once for the wire itself and once for the labor and trench that carry it.

There is a second cost most people miss, and that is voltage drop. Push current through a long wire and some of the power turns into heat along the way. Electricians size up the conductor on long runs to keep that loss small, which means a 100 foot run does not simply cost ten times what a 10 foot run costs in wire. It often needs a heavier gauge of copper on top of the extra length, and copper has not been cheap for years. This is why two quotes for the same charger can be thousands of dollars apart when one garage touches the house and the other sits at the end of the driveway.

One circuit or a subpanel

There are two ways to feed a detached garage. The cheaper way is a single dedicated circuit that serves the charger and nothing else. That is fine if the charger is truly all the building will ever need.

The way we usually recommend is a larger feeder with a small subpanel mounted in the garage. It adds a few hundred dollars to the job, but the garage becomes its own electrical hub. Lights, a door opener, an air compressor, a freezer, or a second charger down the road all come off that subpanel without anyone trenching the yard a second time. If you are already paying to open a trench, dig once and be done. The trench is the expensive part, so the subpanel is cheap insurance.

Overhead or underground

Nearly every job we quote goes underground. Under the 2023 National Electrical Code, which Maryland uses statewide, wire in PVC conduit needs 18 inches of cover and direct burial cable needs 24 inches. Conduit costs a little more in materials, but it protects the wire and leaves you the option of pulling a heavier conductor through later without opening the ground again. On a long run we consider that money well spent.

Before any digging, Miss Utility gets called. That is Maryland’s 811 service, it is free, and it marks the public utilities crossing your property. What it does not mark is your own private lines: the wire to a well pump, the line feeding a septic pump, landscape lighting, an invisible dog fence. Those private lines are everywhere in this county because so many homes here run on wells and septic, so we ask about all of them before the trencher shows up.

What the numbers look like

Those ranges assume the panel at the house has capacity to spare. If it does not, a service upgrade comes first and adds its own cost, and that question gets answered before anything else. Our FAQ covers how we check a panel and what an upgrade runs.

The spread inside each row mostly comes down to digging conditions and wire size. Sandy soil near the water trenches fast. A yard full of mature oak roots slows everything down, and a paved driveway or sidewalk in the path means either cutting it or boring under it. Boring costs more per foot but saves the concrete.

The local wrinkles

Waterfront properties around Solomons and Drum Point are where we see detached garages most often, sometimes with the parking pad closer to the dock than the house. The wire route matters more than the panel on those jobs, so we walk the property before quoting anything.

One sequencing point that catches people who hire the wrong crew: the county electrical permit covers the whole run, and the inspector needs to see the trench at depth before it gets backfilled. Fill the trench early and you may be digging it back up for the inspection. We schedule the backfill around the inspection, and the permit process itself is laid out on our how it works page.

The rebate still applies

Maryland’s residential charger rebate pays half your installed cost up to $700, and installed cost includes the trench, the feeder, the subpanel, and the labor. A detached garage job clears that cap easily, so you get the full $700 back. The current funding cycle opened July 1 and it is first come, first served, so file once the job is done rather than sitting on the paperwork. We wrote up the whole program in our rebate guide.

How to get a real number

A detached garage quote over the phone is a guess, and we do not sell guesses. We look at your panel, walk the route from the house to the garage, measure it, and ask about the private lines in between. Then you get a number that holds up, usually within a day. If the job makes sense, most installs happen within days of the permit clearing.