Most EV charger installs are pretty routine: run a 240V circuit from the main panel to the garage wall, hang the charger, done. But when that garage isn't attached to your house, the job changes entirely. Now you're not just pulling wire — you're getting power from one building to another, and that introduces a whole category of decisions that most homeowners don't know they need to make.

If you've got a detached garage and you want a Level 2 charger out there, here's what's actually involved.

Why Detached Garages Are a Different Animal

An attached garage shares a wall with your house. The electrician can usually access the panel, run conduit through the attic or along the interior wall, and reach the garage without going outside. The whole job might take half a day.

A detached garage requires getting power across open space — a driveway, a yard, a walkway. The two ways to do that are underground conduit or an overhead run. Each has trade-offs, and which one makes sense depends on your property, your local code, and your budget.

Option 1: Underground Conduit (The Clean, Permanent Solution)

This is the preferred approach in most cases, and it's what most electricians will recommend. The basic process: dig a trench between your house and the garage, lay conduit in it, pull wire through, and backfill.

The specifics matter here. Residential electrical code (and most local amendments) requires:

Trench depth of 12 to 18 inches for conduit, depending on jurisdiction and whether the conduit is Schedule 40 PVC or rigid metal
Schedule 40 PVC is the standard choice — it's durable, corrosion-resistant, and cheap
A 240V feed sized for your charger: typically a 60A circuit minimum, wired with 6 AWG copper (or 4 AWG if you want headroom)
Ground fault protection, usually handled at the sub-panel in the detached structure

One thing that catches people off guard: most jurisdictions require a sub-panel in the detached garage, not just a direct circuit. The idea is that any separate structure with power needs its own disconnect. That sub-panel is usually a 60A or 100A unit mounted inside the garage.

Cost range: $1,500 to $4,000

The spread is mostly driven by distance. A 30-foot run from a house with a panel near the back wall is very different from a 150-foot run across a yard. Every 100 feet of additional trench adds roughly $200 to $400 in labor and materials — trenching is slow work, especially if you hit tree roots, hardscape, or rocky soil.

If your property is mostly lawn and the run is under 75 feet, budget closer to $1,500–$2,000. If you're crossing a driveway (which usually requires saw-cutting asphalt or concrete) or the garage is far from the house, you're looking at the higher end.

Option 2: Overhead Run (Cheaper, But With Strings Attached)

An overhead run means running conduit along the exterior of the house, up a wall, and then across to the garage via a cable span. It avoids digging entirely.

Where this is allowed, it can cut the cost significantly. But there are real constraints:

The span cannot be over a driving area unless it's a minimum of 18 feet above grade (12 feet over pedestrian areas)
The wire used for the span must be rated for outdoor/overhead use — typically a type XHHW or USE-2 in conduit, or a purpose-made service entrance cable
Conduit must be NEMA 3R rated (suitable for rain exposure) where it's mounted outdoors
Many jurisdictions don't allow overhead spans for dwelling-to-dwelling or dwelling-to-accessory structure wiring over a certain length, or at all

Check with your local building department before assuming overhead is an option. In some areas it's perfectly fine; in others you'll be told to dig.

Cost range: $800 to $2,500 — but only if code allows it in your area.

If Your Garage Already Has Power

This is the scenario that changes everything. If there's already a 100A sub-panel in the detached garage, adding an EV charger circuit is nearly the same job as an attached garage install. The electrician just needs to confirm the panel has available capacity, run a new 240V circuit to a convenient spot on the wall, and mount the charger.

Cost in this case: $500 to $1,500. Substantially less, because the hard work — getting power to the building — is already done.

If you're not sure whether your garage has a sub-panel, look for a breaker box mounted on the wall. Even older garages with just a light and a couple of outlets often have a small panel hidden behind a shelf or in a corner.

Permit Requirements

You will need a permit for this job. Full stop. Running a new circuit to a detached structure almost always triggers a permit requirement, and the underground work typically requires an inspection before you backfill the trench. Don't skip it — besides the legal exposure, you don't want to dig the trench up later because the inspector couldn't see the work.

A licensed electrician will either pull the permit for you or tell you how to get one. If a contractor offers to do the job without a permit, find someone else.

A Few Practical Decisions Worth Making Now

Upsize the conduit. If you're trenching, the marginal cost of running 2-inch Schedule 40 PVC instead of 1-inch is almost nothing. Do it anyway. If you want to add a second EV charger, run a generator circuit, or add a dedicated circuit for a workshop tool later, you'll be able to pull additional wire without digging again.

Think about sub-panel size. A 60A sub-panel is the minimum that makes sense. A 100A panel costs maybe $150 more to install while you're already doing the work, and it gives you room to add circuits later without replacing the panel.

Plan the charger location carefully. Once the conduit is buried, the interior termination point is more or less fixed. Think about where your car parks, which side the charge port is on, and where on the garage wall makes sense before the electrician commits to a landing point.

Talk to your electrician about the run before they start. A good electrician will walk the route with you, identify any obstacles (irrigation lines, existing conduit, hardscape), and give you a realistic bid. If someone quotes you over the phone without seeing the property, the number may not hold.

Getting power to a detached garage is one of the bigger EV infrastructure projects a homeowner can tackle, but it's straightforward work for an experienced electrician. The key is understanding your two main options, knowing your local code, and making the future-proof decisions — oversized conduit, right-sized sub-panel — while the trench is already open.

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