A detached garage almost always costs more to equip than an attached one, because the power has to travel: the quote is dominated by the distance between your main panel and the garage, the trenching or conduit that distance needs, and whether the garage gets its own subpanel. The charger itself is usually the smaller part of the bill. Exact totals vary widely by site, so the useful question is what drives the price and what to ask for in an itemised quote.
Key Takeaways
- Distance and trenching, not the charger, dominate a detached-garage quote.
- A subpanel costs more now but can serve a second charger or workshop later.
- Matching charger current to the circuit can avoid heavier cable and panel work.
- Ask for an itemised quote with the load calculation shown.
What Drives the Price
In an attached garage the panel is often a few metres from the charger. In a detached garage the circuit may run 15–30 metres or more, crossing a yard or driveway. That one change adds cable, conduit, digging and reinstatement on top of the usual circuit work. The U.S. DOE makes the same point about charging installations generally: labour and site work, not hardware, are what push totals up. For context on the general picture, see why EV charger installation is expensive and how much a home EV charger costs.
| Cost driver | Why it matters | What to ask |
|---|---|---|
| Distance panel to garage | More cable and conduit, more labour, possible voltage-drop upsizing | Is the run measured and itemised? |
| Trenching and reinstatement | Digging under lawn is cheaper than cutting concrete or paving | What surface will be crossed, and who restores it? |
| Subpanel in the garage | Adds a panel, breakers and a heavier feeder cable, but serves future loads too | Is a subpanel included, and what capacity? |
| Panel capacity at the house | A full main panel can add upgrade work before the garage run starts | Did the quote include a load calculation? |
| Permits and inspection | Buried circuits and subpanels are inspected in most areas | Are permit fees in the quote? |
Two Ways to Power a Detached Garage
The first option is a single dedicated circuit run from the main panel straight to the charger. It is the simpler quote when the garage needs nothing else. The second is a subpanel in the garage, fed by one larger cable, with the charger and any lights or outlets on their own breakers. A subpanel costs more on day one, but it avoids a second trench if you later add a second charger or workshop loads. Your electrician will size both the feeder and the charger circuit with the continuous-load rule: breaker at 125% of charger current, so a 40 A charger sits on a 50 A breaker.
Ways to Keep the Cost Down
- Shorten the run. Mount the charger on the garage wall nearest the house, or on the side the cable reaches first. See where to install a home EV charger.
- Match the charger to the circuit. A 32 A setting instead of 48 A can mean a lighter feeder cable and no panel upgrade, while still adding 10–20 miles of range per hour at Level 2.
- Combine the digging. If other yard work is planned, sharing the trench spreads the most annoying cost.
- Use an existing supply. If the garage already has a subpanel with spare capacity, the job may shrink to a short circuit run.
An adjustable charger helps whichever route you choose. The EVDANCE EV-ACT5006T 48A Level 2 wall charger is set to its circuit at installation, so it can run at a lower current on a modest feeder today and be turned up if the supply is upgraded later. If the garage already has a suitable 240 V outlet, a plug-in portable such as the EV-ACS4005T 40A NACS portable charger may avoid new wiring altogether.
Frequently Asked Questions
Is trenching always needed for a detached garage?
Usually the supply is buried in conduit, but some sites allow an overhead run or an existing duct. Your electrician will follow local code for depth and protection.
Can I use the garage’s existing wiring?
Only if it has the capacity. Lighting circuits are not enough for a charger; a load calculation on the existing feeder gives the answer.
Does a detached garage need its own electrical service?
Rarely. Most are fed from the house panel by a single circuit or a subpanel. A separate service is the exception, for very long runs or unusual loads.
Related Reading
- Why Is EV Charger Installation Expensive?
- How Much Does a Home EV Charger Cost?
- How Is an EV Charger Wired?
- Where Should You Install a Home EV Charger?
