If your home still has knob and tube wiring, your homeowners insurance could be at risk, even if you have never had an electrical problem. Across California, insurers are sending non-renewal notices to owners of older homes once an inspector spots the telltale ceramic knobs and tubes in the attic or basement. For homeowners in Pasadena and across the San Gabriel Valley, where entire neighborhoods of Craftsman bungalows and 1920s-era homes were built before modern wiring standards existed, this is quickly becoming a real financial concern, not just an electrical one.
This guide explains what knob and tube wiring is, why insurance companies have turned against it, what California law requires when a policy is not renewed, and what your realistic options are if your home is affected.
What Knob and Tube Wiring Actually Is
Knob and tube wiring was the standard residential wiring method in the United States from roughly the 1880s through the 1940s, and it shows up in plenty of homes built into the early 1950s. The system uses porcelain knobs to anchor individual wires as they run along framing members, and porcelain tubes to protect the wires where they pass through joists and studs. Unlike modern cable, the hot and neutral conductors run separately, spaced apart, rather than bundled together in a single sheathed cable.
The copper conductor itself is not the problem. In fact, older knob and tube wire is often a larger gauge than what is used today. The real issues are age-related: the original rubber and cloth insulation becomes brittle and cracks over decades, the system has no grounding conductor at all, and prior owners frequently spliced into it using methods that would never pass an inspection today.
Why California Insurers Have Turned Against It
Homeowners across California, and the Bay Area in particular, have reported receiving cancellation or non-renewal notices specifically citing outdated knob and tube systems, according to ABC7 News reporting on the trend. Insurance brokers quoted in that coverage put it bluntly: once knob and tube wiring shows up on an application or an inspection report, many carriers decline the policy outright rather than negotiate terms.
Part of this is a broader pattern. California’s insurance market has already tightened significantly because of wildfire exposure, and carriers are looking harder at every risk factor on a property, not just its wildfire zone. An electrical system with no grounding path and degrading insulation is an easy one to flag. Progressive’s own consumer guidance on faulty wiring notes that knob and tube wiring in good condition is not inherently dangerous, but that many insurers will still decline to write a policy or will charge a substantially higher premium because of the perceived fire risk.
In practice, this means a home can have wiring that has functioned without incident for decades, and still lose its coverage the moment an inspector documents it. The insurer is not necessarily reacting to a specific incident. It is reacting to the category of risk.
What California Law Requires When You Are Non-Renewed
If your policy is being non-renewed, California Insurance Code Section 678 requires your insurer to mail written notice at least 60 days, but no more than 120 days, before the policy’s expiration date, and that notice must state the specific reason for the non-renewal. You are entitled to know exactly why the insurer is walking away from the risk, and the notice must include contact information for the insurer’s representatives.
The California Department of Insurance is the state agency responsible for enforcing these notice requirements and for reviewing complaints when homeowners believe a non-renewal was handled improperly. If you receive a notice with less time than the law requires, or if the stated reason seems inaccurate, the department is the right place to raise it. Knowing this timeline matters because it defines how much runway you actually have to either replace the wiring or shop for a new policy before your current coverage lapses.
How to Tell If Your Pasadena or San Gabriel Valley Home Is Affected
Knob and tube wiring is usually easiest to spot in an unfinished attic or basement, where the ceramic knobs and tubes are visible along exposed framing. A few practical signs to check for:
- Two-prong outlets throughout the home, especially in original, unremodeled rooms
- Cloth-covered wiring visible at the electrical panel or in an attic
- A home built before 1950, particularly in older Pasadena neighborhoods like Bungalow Heaven, Oak Knoll, or Madison Heights, where entire blocks share the same original construction era
- A fuse box, or a panel that was clearly upgraded at some point while leaving older branch circuits untouched
Homeowners sometimes assume that a prior owner’s kitchen remodel or a panel swap means the wiring is current throughout the house. In practice, it is common for only the circuits directly involved in a renovation to get rewired, while original knob and tube runs stay in place feeding bedrooms, hallways, and closets that were never touched.
Why a Partial Fix Rarely Satisfies an Insurer
As our electrician Razmik puts it, “Homeowners often want to just patch the one section an inspector flagged, but insurers are looking at the whole system, not one outlet. If knob and tube is still live anywhere in the house, most carriers treat the risk the same as if nothing had been touched.”
This is one of the more frustrating realities for homeowners trying to satisfy an insurance requirement on a budget. Replacing a single visible run in the attic does not remove the underlying wiring feeding the rest of the house, and an inspector who returns for a follow-up will typically still find active knob and tube elsewhere.
What Replacement Actually Involves and Costs
A full rewire replacing knob and tube with modern grounded copper wiring is a significant project, and the price depends heavily on how accessible the wiring is. Homes with open attics and basements are considerably cheaper to rewire than homes with finished plaster ceilings and no crawl space, since the electrician has to “fish” new wire through closed walls rather than working from open framing.
Costs nationally tend to fall in the range of roughly $10 to $20 per square foot for a full rewire, though older homes with lath-and-plaster walls, multiple stories, or difficult access can push toward the higher end of that range or beyond. Most projects also involve a panel evaluation, since a home still running on knob and tube circuits often has an outdated panel that cannot support modern amperage needs alongside the new wiring.
The table below breaks down the typical project phases and what tends to drive cost up or down at each stage.
It is worth budgeting for drywall and plaster repair as a separate line item, since most of the cost variability in an older home comes down to how much of the house has finished walls with no attic or basement access.
The Buying and Selling Angle Most Guides Skip
Knob and tube wiring does not just threaten your existing policy. It can also complicate a home sale. Buyers in Pasadena’s older neighborhoods increasingly ask about wiring type before making an offer, since their own future insurability depends on it. It is common for a home inspection to flag active knob and tube, at which point a buyer’s lender may require a plan for replacement before approving financing, and the buyer’s own agent may push for a credit or a pre-closing addendum requiring the wiring be addressed.
Sellers who get ahead of this, either by replacing the wiring before listing or by having a clear, documented plan and quote in hand, tend to have a much smoother path through escrow than sellers who are caught off guard by an inspection report.
What to Do If You Find Knob and Tube in Your Home
The first step is a proper inspection by a licensed electrician, not a guess based on outlet types alone. A licensed electrician can confirm how much of the home is actually still on the original system, since many older homes have a mix of upgraded and original circuits. From there, you can get a written quote for full replacement, or discuss whether a phased approach makes sense for your budget and timeline.
If you already have a non-renewal notice in hand, it is worth contacting your insurer directly to ask whether a documented plan for replacement, or a partial rewire completed within a set window, would allow reinstatement. Some carriers will work with homeowners who show clear progress rather than simply denying every application from an affected property.
“A lot of Pasadena homeowners are surprised to learn their beautiful 1920s bungalow still has the original wiring behind the walls. It’s not always obvious until an inspector opens up the attic access.”
– Razmik, Red Electricians
Electrical fires connected to distribution and lighting equipment remain one of the leading causes of home fire property damage nationally, and NFPA’s home electrical fires research is a useful reference point for understanding why insurers treat aging wiring systems as a meaningful risk factor rather than a cosmetic concern.
Grounding, GFCI Substitution, and What Modern Code Actually Requires
One detail that surprises a lot of homeowners is that a full rewire is not always the only path to a code-compliant fix for individual circuits. In some cases, a licensed electrician can install GFCI protection as a code-recognized substitute for a missing ground at specific outlets, buying time or addressing a specific problem area without a whole-house rewire. This is not a substitute for addressing active knob and tube wiring broadly, but it illustrates why a licensed electrician’s assessment matters more than a blanket “replace everything now” approach. Every home is different, and the right scope of work depends on what your electrician actually finds circuit by circuit.
If You Are Already Struggling to Find Coverage
Homeowners who are non-renewed specifically because of knob and tube wiring sometimes assume their only option is the California FAIR Plan, the state’s insurer of last resort for properties that cannot find coverage on the standard market. The FAIR Plan can be a temporary bridge, but it typically offers more limited coverage and higher costs than a standard policy, and it is worth treating as a stopgap rather than a long-term plan.
A more durable path for most homeowners is addressing the wiring itself, then shopping the improved property to admitted carriers who were previously unwilling to write a policy. Once a licensed electrician documents that the knob and tube has been fully replaced, many insurers that declined the original application will reconsider, since the underlying risk factor they were reacting to no longer exists. Keeping the electrician’s invoice, permit, and final inspection sign-off on hand makes this conversation much easier when you go back to an agent or a new carrier.
Why Pasadena’s Housing Stock Makes This a Local Issue, Not Just a State One
Pasadena’s identity as a city is tied closely to its historic housing stock. Neighborhoods like Bungalow Heaven were specifically built out in the 1900s to 1920s Craftsman era, and much of that construction predates any grounding requirement in residential wiring. That means the insurance risk being discussed here is not a rare edge case for a handful of unlucky homeowners. It is a structural feature of the city’s oldest and often most desirable neighborhoods, which is exactly why local homeowners benefit from understanding this issue before it shows up as a surprise on an insurance renewal or a real estate inspection report.
Renovation activity across these neighborhoods has been steady for years, but a kitchen or bathroom remodel does not automatically touch the wiring in a bedroom down the hall. It is common for an electrician responding to an unrelated wiring repair call for a flickering light to discover knob and tube still active in parts of the house the homeowner assumed had already been modernized decades ago.
Protecting Your Coverage Starts With an Accurate Assessment
Whether you are trying to keep your current policy, prepare for a sale, or simply want peace of mind about a home you have lived in for years, the starting point is the same: get a licensed electrician to document exactly what is in your walls. Guessing based on outlet style or a partial view of the attic can lead to either unnecessary spending or a false sense of security, neither of which serves you well when an insurance renewal or a real estate transaction is on the line.
Red Electricians provides knob and tube wiring assessments and full replacement services for homeowners throughout Pasadena and the surrounding San Gabriel Valley. If your home also has older aluminum branch circuits alongside the knob and tube system, our aluminum wire replacement service addresses that separately. If you are dealing with an insurance notice, a home sale, or simply want to know what is behind your walls, our licensed electricians can walk you through exactly what your home needs and what it will take to get there.
