If you own a pre-1950s home in San Francisco, Oakland, Berkeley, or anywhere on the Peninsula, there's a good chance some of your wiring is still knob and tube. It's also the single most common reason homeowners insurance carriers refuse, non-renew, or cancel a policy in the Bay Area.
What is knob and tube wiring?
Knob and tube (K&T) is the original residential wiring method used from roughly 1880 to the 1940s. Hot and neutral wires run separately through ceramic knobs and protective tubes. It was safe when installed, but it has no ground conductor, insulation degrades, and decades of DIY modifications often leave it spliced into modern circuits in unsafe ways.
Why insurance carriers won't cover it
Carriers see active knob and tube as a fire-risk and liability concern for three main reasons:
- No equipment ground — modern appliances and electronics have nowhere to fault to.
- Insulation contact — blown-in attic insulation traps heat against bare conductors.
- Overloaded circuits — original 15A circuits are routinely pushed past their limit.
Most major California insurers (State Farm, Allstate, Farmers, Travelers, CSAA) either decline new policies or require full removal at renewal. A few specialty carriers will write a policy, but you'll pay a steep premium.
How a rewire resolves the issue
A licensed electrician removes or permanently de-energizes every active K&T run and replaces it with modern grounded NM-B (Romex) or conduit, pulls permits, and coordinates the final inspection with your local building department. In most Bay Area homes we pair the rewire with a 200A panel upgrade so you get a clean, code-compliant electrical system end-to-end.
What your insurance company needs from us
After final inspection we provide a signed letter on company letterhead with our CA license number (CA Lic. #1141155), the scope of work, and explicit confirmation that no active knob and tube remains. That letter is what carriers ask for to bind or reinstate coverage.
Frequently asked questions
- Will my homeowners insurance cover knob and tube wiring?
- Most major carriers in California will not write or renew a policy on a home with active knob and tube wiring. A few specialty insurers will, but premiums are significantly higher and coverage is often limited.
- Do I have to replace all of the knob and tube to get insured?
- Usually yes. Insurers generally require a licensed electrician's letter confirming that all active knob and tube has been removed or de-energized and replaced with modern Romex or conduit.
- How much does it cost to rewire a Bay Area home?
- Whole-home rewires in San Francisco and the Peninsula typically range from $12,000 to $35,000+ depending on size, access, finishes, and whether a panel upgrade is included. We provide flat-rate written quotes after an on-site assessment.
- Can you provide the documentation my insurance company needs?
- Yes. After we complete the rewire and pass final inspection, we provide a signed letter on company letterhead with our CA license number, scope of work, and confirmation that no active knob and tube remains.
Get a free rewire estimate
We've rewired hundreds of Bay Area homes — Victorians in the Mission, Craftsmans in Berkeley, mid-century ranchers on the Peninsula. Tell us about your home and your insurance situation and we'll come out, assess the scope, and send a flat-rate written quote.
Request a free estimate or call us directly at (415) 488-3112.