Why Does Running Power to a Detached Garage Feel So Complicated?

I’ve run into this same dilemma with clients who want to convert garages or sheds into studios or workshops. The “how much is too much” question comes up every time. I think you nailed it with this:

I didn’t want to go crazy and end up with a panel that looks like it belongs in a factory...

There’s definitely a balance. In my experience, most people don’t regret going a little bigger, but I have seen setups where it was just overkill - like a 100-amp subpanel for a space that never saw more than a few power tools and a mini fridge. That’s money and space you could use elsewhere.

A practical rule of thumb I’ve picked up: add up the wattage of everything you know you’ll use, then tack on 25-30% for “future stuff.” For most detached garages or sheds, a 60-amp subpanel is more than enough unless you’re planning to run heavy machinery or charge an EV. If you’re just thinking about an electric mower, some lights, and maybe a heater, you probably won’t need more than that.

Wire gauge is trickier since it depends on both the amperage and the distance from your main panel. Longer runs need thicker wire to prevent voltage drop. There are calculators online, but I usually recommend at least #6 copper for a 60-amp panel if you’re running more than 50 feet.

I’ve seen people regret not planning for 240V, especially as more tools and appliances go electric. But I’ve never heard anyone say, “I wish I’d put in a smaller conduit.” The extra cost is usually minimal compared to the hassle of digging again.

That said, I wouldn’t stress about “future-proofing” for every possible scenario. Unless you’re planning to open a woodworking business out there, you probably don’t need industrial capacity. Just leave yourself some wiggle room - space in the panel for extra breakers, maybe an extra conduit if you’re really unsure.

It’s easy to overthink it, but as long as you’re not going way beyond your realistic needs, a little extra capacity is usually a good investment.

If you’re just thinking about an electric mower, some lights, and maybe a heater, you probably won’t need more than that.

I get the logic behind “just leave yourself some wiggle room,” but I’ve actually seen a few clients go overboard with future-proofing and end up with a space that feels more like a utility closet than a creative studio. Sometimes less is more, especially if you want the vibe to be inviting and not dominated by panels and conduit. Have you ever had someone regret not going bigger, or is it usually just a case of overestimating what they’ll actually use? I always wonder if we’re too quick to assume we’ll need all that extra capacity.

I’ve actually seen both sides of this. One guy I worked with insisted on a 100A subpanel “just in case,” and now it’s mostly empty space and a lot of conduit he wishes he’d hidden better. On the flip side, I’ve only had one person regret not going bigger, and that was after they bought a welder on a whim. Most folks end up using way less than they thought. It’s easy to get caught up in the “what ifs,” but honestly, unless you’re planning to open a machine shop, you’re probably fine keeping it simple.

Totally relate to the “what if” spiral - been there, done that, bought the oversized panel. It’s wild how easy it is to overthink garage power. Unless you’re planning to host a laser light show, simple usually wins. Less is more... and way less conduit to hide later.

I swear, every time I start a project in my 1920s place, I end up knee-deep in “what if” scenarios. Last time I ran power to the garage, I convinced myself I’d need enough juice for a full-blown workshop... and now I’ve got outlets everywhere but still just use it for the lawnmower and some Christmas lights. Hiding conduit in old brick? Not fun. Sometimes I think the ghosts of previous owners are laughing at me for overthinking it.