Power for the new space

The building is the visible part of the project. The electrical question underneath it is simpler and harder: how does power get from your existing service to a structure that did not exist, in a size that will not embarrass you later. A detached shop wired for two lights and an outlet becomes a regret the day the welder or the table saw arrives.

Feeder and sub-panel come first

For a detached structure, the backbone is a feeder from your main service to a sub-panel in the new building. We size both against what the space will actually run: shop tools with big startup draws, an ADU's kitchen and laundry and heat, or a garage that might charge a car someday. Trenching depth, conduit, and routing get settled before anyone pours or builds over the path.

What each kind of space needs

• ADUs: a full dwelling's electrical, from kitchen small-appliance circuits to smoke detector interconnects, plus the metering question your city will have opinions about.
• Shops: 240V tool circuits, dust collection, compressor, bright even lighting, and outlets every few feet because a shop never has enough.
• Garages: openers, freezer or fridge circuits, EV charging rough-in even if the car is still hypothetical.
• Additions: circuits, lighting, and heating tied cleanly into the existing panel, with a capacity check first.

Sized for next year, not just move-in

The cheapest time to add capacity is while the trench is open and the walls are studs. A sub-panel with a few spare spaces, one wire gauge up on the feeder, an empty conduit under the slab: these cost little now and save you a second project later. We will lay out the trade-offs and let you decide with real numbers in front of you.

Permits follow the structure

ADUs and additions involve building and electrical permits, and detached structures have their own rules that vary between Pierce, King and Snohomish County jurisdictions. We handle the electrical permit and inspections for our scope and coordinate timing with your builder so cover inspections never hold up framing or insulation. The details live in our detached garage and shop guide and the ADU planning guide.

Questions to settle before the trench is dug

• Is the feeder sized for what this building will run in five years, or only on opening day?
• How many spare spaces will the sub-panel carry?
• How will the ADU be metered, and has the city already weighed in?
• Does the detached building get its own grounding electrode system, and is it in the price?

What a thin bid leaves out

Watch for a number with no trench depth or route in it, no mention of spare conduit while the ground is open, and no capacity check on the service that must feed it all. If an existing outbuilding currently runs on an extension cord through a window, tell every bidder so; that is a symptom to cure, not a baseline to extend.

Protecting the investment once it is buried

Keep a drawing of where the feeder runs and plant nothing woody over it, learn where the structure's disconnect sits before you ever need it, and keep both panel directories honest as the space picks up new equipment. The general guides on preparing for an electrical estimate and comparing bids past the bottom line hold for outbuildings just as they do for houses.

Bring us in while the project is still on paper. Tell us what you're building and what will live in it, or call (206) 718-3047. Site plans and a photo of your existing panel make the first conversation concrete.