Knob and tube wiring

An early type of electrical wiring found in some pre-1950 homes. Insurers often decline to cover homes with active knob and tube, so it usually needs to come out before closing.

Property condition · Updated September 2026

In a room, this word explains itself where it appears.

Every term like this one lights up in the step you're on.

Free to set up. No credit card.

Part 1 of 4

Why a seller cares

Active knob-and-tube in a pre-1950 home can stop a buyer's insurance, and no insurance means no loan. It is one of the few inspection findings that can end a financed sale rather than reprice it.

Part 2 of 4

A simple example

The inspector finds active knob-and-tube in the attic of your 1928 home. The buyer's insurer declines to write a policy until it is replaced.

Knob and tube wiring: a simple example
What is foundWhat tends to follow
Active knob-and-tubeA rewire before closing, or a buyer who cannot get insurance
Old wiring left in place but disconnectedUsually fine, with an electrician's letter
Rewired years ago with permitsA selling point, and a question answered before it is asked

Knob-and-tube is an insurance problem before it is an electrical one.

Part 3 of 4

What people get wrong

That it is only a concern if it looks damaged. Insurers decline it on sight, damaged or not.

Part 4 of 4 · where to read next

Where it appears in the sale

What a definition is, and what it isn't

Keighbor is a software company, not a law firm, brokerage, or tax adviser. This is general information, not legal, tax, financial, or real estate advice about your sale. Your situation may differ. Before acting on a contract, disclosure, title, tax, or pricing question, ask an appropriately licensed professional in your state.

Written and researched by Keighbor Research · drawn from the reference glossary · how we research and check what we publish

Was this clear?

One piece of your sale. Here is where all the pieces live.

In your room, this word explains itself where it appears.

Keighbor keeps your whole home sale in one place and defines every term like this one right where you meet it, in the step you're on. Free to set up, with or without an agent.

Set up my roomFree to start. No credit card.