Can Knob and Tube Wiring Affect Homeowners Insurance in California?

Yes, knob and tube wiring can affect homeowners insurance in California. An insurance company may ask about the wiring during a new application or renewal, request an electrical inspection, require certain electrical work, or decide the property does not meet its underwriting requirements. The exact response depends on the insurer and the condition of the home.

At TNT Electric Co., we work on older electrical systems throughout Citrus Heights and the Greater Sacramento area, including knob and tube rewiring. If an insurer has raised a question about your wiring, start by finding out exactly what it wants documented or corrected before assuming you need a particular repair.

Why Knob and Tube Wiring Gets an Insurer’s Attention

Knob and tube wiring is an older wiring method found primarily in homes built before modern grounded electrical systems became standard.

The system uses individual conductors supported by porcelain knobs and protected by porcelain tubes where wires pass through framing. Unlike modern residential cable, traditional knob and tube wiring does not include an equipment grounding conductor.

Age is another issue. Even if the original installation was properly completed, the wiring has often been in the house for many decades. During that time, insulation can deteriorate, connections can be altered, circuits can be extended, and previous renovations can introduce conditions that were not part of the original installation.

Insurance underwriting looks at property risk. Older electrical systems can become part of that evaluation because insurers want to understand the likelihood and potential severity of an electrical loss.

That does not mean every California insurance company treats knob and tube wiring the same way.

Knob and Tube Wiring Insurance in California Depends on the Carrier

There is no single statewide rule saying that every California home with knob and tube wiring is automatically uninsurable.

Insurance companies establish their own underwriting requirements within California insurance regulations. One carrier may consider the home after receiving an electrical inspection. Another may want active knob and tube circuits replaced before issuing or renewing a policy. A different insurer may simply choose not to write that particular property.

That distinction matters if you are shopping for coverage.

The California Department of Insurance advises homeowners to compare insurers because companies do not necessarily write every property or area of the state. If standard coverage becomes difficult to obtain, the department also explains the role of the California FAIR Plan and supplemental coverage options.

An electrician cannot tell you what an insurance company will cover or how it will price a policy. Those questions need to go directly to the insurer, broker, or licensed insurance agent.

We can determine what electrical system is actually present and what condition it is in.

Finding Knob and Tube Does Not Automatically Tell You Its Condition

Seeing porcelain knobs in an attic or crawlspace tells you that knob and tube wiring exists or existed in the home. It does not tell you whether those conductors are still energized.

Some older homes contain abandoned knob and tube wiring alongside newer electrical circuits. In other houses, portions of the original system remain active while remodeled areas have newer wiring.

That is an important distinction for both the electrical evaluation and any conversation with an insurer.

A licensed electrician can trace circuits and determine which wiring is still serving lights, receptacles, or other loads. The inspection may also reveal later alterations that need attention.

Old wiring should not be evaluated from age alone. Its condition, configuration, modifications, grounding, circuit loading, and interaction with newer electrical work all matter.

What an Insurance Company May Ask You to Provide

If an insurer questions the electrical system, read the notice carefully before scheduling work.

The company may be asking for information rather than immediately requiring a complete rewire. For example, it may want confirmation of the wiring type, an electrician’s evaluation, photographs, permit records for previous work, or documentation showing that outdated wiring has been replaced.

If replacement is required, ask what documentation the insurer expects when the project is complete.

Keep the request in writing if possible. That gives both you and the electrician a clearer target.

A vague statement such as “the insurance company has a problem with the electricity” does not tell us enough. A notice stating that the carrier needs confirmation that active knob and tube wiring has been removed is much more specific.

Does Knob and Tube Wiring Always Require a Whole-House Rewire?

The electrical system needs to be evaluated before determining the scope.

A house may have knob and tube throughout most of the structure. Another may have modern wiring in renovated areas but a few older circuits remaining in bedrooms or lighting locations.

The physical layout matters too. Attic access, crawlspace access, plaster walls, previous remodeling, circuit locations, and the existing electrical panel all affect how a rewire needs to be approached.

Our whole-house rewiring service covers homes where the existing wiring requires a broader update. We also evaluate the existing system first so the scope reflects what is actually in the house rather than assuming every older property needs identical work.

If your insurer has specifically required all active knob and tube wiring to be replaced, a limited repair to one circuit may not satisfy that requirement. Confirm the carrier’s conditions before deciding how far the project needs to go.

Why Replacing One Outlet Does Not Remove the Insurance Issue

Homeowners sometimes discover knob and tube wiring after an inspector sees two-prong outlets and assume replacing those receptacles will solve the problem.

The outlet is only the visible end of the circuit.

Installing a modern-looking three-prong receptacle does not add a grounding conductor to older wiring. It also does not replace the conductors running through the walls or attic.

The underlying circuit matters.

Similarly, replacing an electrical panel does not automatically replace old branch wiring throughout the house. A newer panel and knob and tube circuits can exist in the same property.

This is why an insurance request involving an “electrical system” needs clarification. The carrier may be concerned about the panel, the branch wiring, or both.

TNT Electric recently covered this distinction from the panel side in our article on what to do when a homeowners insurer flags an electrical panel. Knob and tube wiring is a separate part of the electrical system and should be evaluated separately.

What If You Are Buying a House With Knob and Tube Wiring?

Insurance questions are worth addressing before the transaction reaches the last few days before closing.

If an inspection identifies knob and tube wiring, contact your insurance professional and ask whether it affects the policy you plan to purchase. Do not assume the seller’s existing coverage means a new carrier will accept the property under the same conditions.

You should also determine how much of the home’s electrical system still uses knob and tube.

A small amount of abandoned wiring is a different situation from active circuits throughout the house. An electrical evaluation gives you better information for planning the project and discussing the property with your insurer.

If replacement will be required, knowing that before closing also gives you time to understand the scope rather than discovering an insurance condition after you have already moved in.

What to Do If Your Insurer Flags Knob and Tube Wiring

Start with the insurance notice.

Find out whether the company is requesting an inspection, documentation, partial correction, complete replacement of active knob and tube wiring, or something else. Ask for the requirement and deadline in writing.

Then have the electrical system evaluated.

An electrician should determine where active knob and tube wiring remains, what circuits it serves, how it has been modified over time, and what replacement work would be necessary. If the insurer has supplied specific documentation requirements, share those before the work begins.

Once the required electrical work is complete, keep your invoices, permit or inspection records when applicable, photographs, and any other documentation your insurance company requested.

Do not assume that completing electrical work automatically changes your insurance premium or guarantees that a particular carrier will issue a policy. The insurer makes that decision.

Get the Wiring Identified Before Planning the Rewire

Knob and tube wiring can affect homeowners insurance in California, but the outcome varies by insurance company and property. The useful first step is finding out what wiring is still active and exactly what the carrier requires.

If your Citrus Heights or Sacramento-area home has knob and tube wiring, TNT Electric Co. can inspect the electrical system and explain what would be involved in replacing the remaining outdated circuits.

If an insurer has already sent you a notice, have it available when you contact us. That keeps the electrical evaluation focused on the actual condition the insurance company has identified rather than guessing at what it might want.