What Is Knob-and-Tube Wiring?
Knob-and-tube (K&T) wiring is an early electrical system installed in homes from the 1880s through the 1930s. It uses ceramic knobs to support wires and ceramic tubes to protect them as they pass through framing.
Many historic neighborhoods in Portland and Beaverton, including Laurelhurst, Sellwood, Irvington, Cedar Hills, and Multnomah Village, still contain homes with original knob-and-tube wiring.
While it may still “work,” that doesn’t mean it’s safe by today’s standards.
Why Knob-and-Tube Wiring Is a Problem
Knob-and-tube systems were never designed for modern electrical demand. Today’s homes use significantly more power for appliances, HVAC systems, EV chargers, and electronics.
Common Issues with Knob-and-Tube Wiring
- No grounding (increases shock risk)
• Cloth and rubber insulation that deteriorates over time
• Fire risk from overheating
• Unsafe DIY splices added over decades
• Cannot safely support modern loads
In Oregon, knob-and-tube wiring is considered obsolete and does not meet current electrical code.
Is Knob-and-Tube Wiring Legal in Oregon?
Knob-and-tube wiring is not illegal to leave in place if it is untouched and functioning properly. However:
- It cannot be extended or modified
• It must be removed or replaced during remodels
• It often fails home inspections
• Insurance companies frequently refuse coverage
Most insurers in Portland and Beaverton will require full replacement before issuing or renewing a policy.
Signs Your Home Still Has Knob-and-Tube Wiring
You may have knob-and-tube wiring if you notice:
• Two-prong outlets throughout the home
• No ground wire in outlets
• Brittle or fraying cloth insulation
• Ceramic knobs visible in the attic or basement
• Frequent breaker trips after partial upgrades
A licensed electrician can confirm with a proper inspection.
Cost to Replace Knob-and-Tube Wiring in Portland & Beaverton
The cost to remove and replace knob-and-tube wiring depends on home size, accessibility, and how much wiring remains.
Typical Price Ranges
- Partial replacement: $3,000–$6,000
• Full home rewiring: $8,000–$20,000+
Factors that affect cost:
• Square footage
• Wall and ceiling access
• Number of circuits
• Panel condition (may require an upgrade)
• Permit and inspection requirements
Smiley Electric provides transparent, upfront estimates after an in-home evaluation.
Do You Need a Panel Upgrade Too?
Many homes with knob-and-tube wiring also have:
• 60-amp or 100-amp panels
• Unsafe brands (FPE, Zinsco, Split-Bus)
• No capacity for modern appliances
In many cases, rewiring and panel upgrades go hand-in-hand, especially for EV chargers, heat pumps, or kitchen remodels.
Permits & Inspections in Portland
- Electrical permits are required for rewiring
• Inspections are handled through the City of Portland or Washington County (Beaverton)
• All work must meet NEC and Oregon Electrical Specialty Code
Smiley Electric handles permits, inspections, and coordination, so homeowners don’t have to.
Should You Replace Knob-and-Tube Wiring?
Replacement is strongly recommended if:
• You’re remodeling
• You’re selling or buying a home
• Your insurance flagged the wiring
• You experience flickering lights or warm outlets
• You want peace of mind and safety
Replacing knob-and-tube wiring increases home value, safety, and insurance eligibility.
Knob-and-Tube Replacement Experts in Portland & Beaverton
Smiley Electric specializes in:
• Knob-and-tube removal
• Whole-home rewiring
• Electrical panel upgrades
• Code compliance for older homes
We proudly serve Portland, Beaverton, Hillsboro, Tigard, Lake Oswego, and surrounding areas.
📞 Schedule a professional inspection today and get a clear, honest quote.