If you’re adding a garage workshop, backyard shed, or accessory dwelling unit (ADU) in the Portland metro area, you may need a subpanel installation. Subpanels are smaller breaker boxes that branch off from your home’s main electrical panel—simplifying wiring, increasing safety, and improving system efficiency.
At Smiley Electric, your trusted Beaverton electrician, we specialize in code-compliant subpanel installations for garages, ADUs, shops, and outdoor structures across Portland and beyond.
Here’s everything you need to know before starting your project.
What Is a Subpanel?
A subpanel is a smaller breaker box fed from your home’s main service panel. Instead of running every circuit back to the main panel, a subpanel lets you power multiple circuits in a detached or remote area using a single feeder line.
Common uses for subpanels in Portland-area homes:
- 60 A garage subpanel for lighting and power tools
- 100 A ADU subpanel for kitchens, laundry, and HVAC
- 125 A shop subpanel for welders, compressors, and woodworking tools
When you search “electrician near me for subpanel installation Beaverton”, this is exactly the type of project Smiley Electric handles every week.
When to Add a Subpanel
Homeowners in Beaverton, Portland, and Hillsboro often need a subpanel when:
- Detached structures (garages, shops, or sheds) are too far to run circuits individually
- ADUs or remodels need a separate power distribution point
- High-demand equipment like EV chargers, hot tubs, or shop tools require dedicated capacity
- Full main panels leave no room for additional breakers
Hiring a licensed electrical contractor in Portland ensures your system remains safe, expandable, and inspection-ready.
Sizing Your Subpanel
Proper subpanel sizing determines both safety and flexibility.
Subpanel Size | Ideal Use Case |
60 A | Small sheds or detached garages (basic lighting & outlets) |
100 A | ADUs, shops, or garages with major appliances |
125–200 A | High-demand workshops or partial home additions |
💡 Pro Tip: In many Beaverton homes, we recommend a 100 A subpanel even if you only need 40 A today. This prepares your property for EV chargers, HVAC upgrades, or new tools down the line.
Feeder Wire Types & Conduit
Selecting the right feeder wire ensures your subpanel is both safe and Oregon code compliant:
Amperage | Copper | Aluminum |
60 A | #6 AWG | — |
100 A | #3 AWG | #1 AWG |
200 A | — | 2/0 AWG |
For underground feeders to detached structures, wiring must be buried 18–24 inches deep.
Choosing Smiley Electric means your installation will pass inspection the first time.
Grounding & Bonding Basics
Subpanels must be wired differently from main panels:
- Neutrals and grounds must remain isolated in subpanels.
- No bonding screw in the subpanel (bonding occurs only in the main panel).
- Detached structures—garages, shops, and ADUs—require ground rods near the subpanel.
⚠️ Many DIY setups fail here, leading to shock or fire hazards. That’s why hiring a licensed Beaverton electrician is essential.
🚫 Common Mistakes We See
- Shared neutrals without handle ties
- Neutrals and grounds improperly bonded
- Undersized feeder wire for breaker rating
- Missing permits or failed inspections
These errors can void homeowner insurance or cause electrical fires.
If you’re searching “licensed electrician near me Beaverton for subpanel work”—look no further than Smiley Electric.
✅ Permit & Inspection Checklist (Oregon)
When you hire an electrical contractor in Portland or Beaverton, inspectors typically check for:
- Correct breaker size in main panel
- Proper feeder wire gauge
- Neutral/ground isolation in subpanel
- Ground rods for detached buildings
- Clear labeling of circuits
- NEC 110.26 clearances (30” wide × 36” deep × 6.5’ high)
Smiley Electric handles permits, scheduling, and inspection prep so you don’t have to.
Why Choose Smiley Electric?
✅ Local expertise — Deep knowledge of Portland-metro code requirements
✅ Licensed & insured — Your safety is always our top priority
✅ Future-proof designs — We size subpanels for tomorrow’s needs, not just today’s
Whether you’re installing a garage subpanel in Hillsboro, an ADU subpanel in Beaverton, or a shop subpanel in Portland, our team ensures your project is safe, reliable, and built to last.