Want to Power Up Your Detached Garage? Here's How an Electrician Can Do It

Ben Kissam
Written by Ben Kissam
Updated February 9, 2022
Home garage with door open at night
Photo: Thomas Barwick / Stone / Getty Images


  • For the majority of DIYers, outsourcing electrical work is the safest option.

  • You’ll likely need to dig a trench from your home to the garage (or hire someone to do it).

  • Always call 811 before digging in your yard.

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Picture this—your detached garage, currently home to a bunch of power tools and storage boxes, suddenly has lights. You turn that additional living space into a home office or an entertainment center, or even a workspace for your home improvement projects.

Sounds pretty great, but getting electricity to a detached garage does require lots of know-how and hard work. It’s the type of job best left to a local electrician, but what’s the process look like? This guide explains how an electrician runs power to a detached garage.

1. They Will Determine Your Electrical Needs to Select a Breaker Box

Closeup of an electrician wiring circuit braker unit
Photo: grigvovan / Adobe Stock

How much electricity do you need in your detached garage? This is the first question an electrician is going to ask, as it’s going to impact the size of the breaker box they install in the garage. It’s questions like this that make this project one of several home improvement projects you should hire an electrician for.

One formula electricians use is to multiply three by the square footage of the area receiving electricity to determine total wattage. If you plan to run a refrigerator or several power appliances in a work area, a 100-amp box is likely where you’ll start.

Hiring an electrician to install a new breaker box costs between $200 and $2,000.

2. They Will Advise You to Call Your Local Utility Locating Service

Red utility flag on a yard
Photo: videotrinkets / Adobe Stock

Before beginning the project, you or your electrician will need to call to make sure no buried gas lines or electric cables are already present beneath your yard. Failure to do so could result in serious injury, not to mention expensive repairs, fines, or disrupted utility services to your home.

811 is the national call-before-you-dig hotline to call. Never skip this step before your pro starts this project.

3.They Will Dig a 12-Inch Trench From Your Home to the Detached Garage

Electric pipe line buried in trench
Photo: lufeethebear / Adobe Stock

Electricians rarely do the excavating themselves, but you’ll likely need to dig (or hire someone to dig) a foot-deep trench that runs from your home to the point of installation in your detached garage.

Digging a trench usually costs between $800 for 100 linear feet of digging, although this price can change depending on the difficulty of the terrain. You can hire a local excavation company to do this job.

Keep in mind this is just part of your budget. Powering up your outdoor living space will likely cost between $1,000 and $2,500 on average.

In this trench, your electrician will bury a UF-B cable, which is a waterproof cable that transports electricity to your garage.

4. They Will Install a Pipe for Any Exposed Areas

Electrician holding protective electric pipe
Photo: Tomasz Zajda / Adobe Stock

In many cases, especially for homes with a foundation that is just slightly outward away from the home, an electrician will need to install a pipe that runs from the insertion point of your home into the ground. Otherwise, you’ll have an exposed UF-B cable above the ground.

Conduit pipes are a popular option here, as they can be heated up and bent to fit sleekly along the existing contours of your home. Once this is in place, the electrician can run the UF-B cable from the new breaker box to the existing panel inside your home.

6. They Will Suggest You Lay Sand Down in the Trench (as a Warning for Future Digging)

Sand covering trench in a yard
Photo: Stephen / Adobe Stock

Your electrician or a local electrical company also won’t contribute to this part, but it will be a required step to complete this job. A local trench digging or excavation company can tackle this job, or maybe even a handyman if they have experience.

Using a bag of sand to fill in the base of the trench you've dug serves as a warning for future diggers—possibly even the next homeowners of your current residence—that electric cables lay below it.

It’s also a good idea to put down red electrical tape on top of the sand, then cover it with dirt.

7. They Will Wire Your New Electrical Box, Then Test It

Hand testing a home electrical box
Photo: The Toidi / Adobe Stock

Your home’s electricity must be turned off before starting any wiring, which should always be tackled by a professional electrician.

Finally, your electrician will connect your detached garage to the main power source. This job involves identifying and wiring together electrical cables and should only be tackled by someone with a true understanding of what they’re doing. Any other situation could pose a serious safety hazard.

Once completed, turn your power back on and, well, let there be light! (Or a cold fridge, or whatever it is that you needed electricity for in your detached garage.)

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