P 425.337.3006 | C 425.327.2609
Electronics Gallery What's New

Knob and Tube Rewire

The vast majority of homes in the Puget Sound region are of relatively older construction that date back to the early 1900s.  Many people know this.  Many people also know that older homes, from an electrical viewpoint, mean knob and tube wiring.  However, many home owners are still perplexed as to what knob and tube actually means and whether this wiring is actually safe for their home.

Alpha and Omega Electric provides quality electrical services throughout the Puget Sound region.  We are dedicated towards providing not only services, but solutions that match your needs and the needs of your home.  We understand the perhaps complex issues surrounding knob and tube wiring; and, as always, we are here to inform you so that you can find the solutions that work best for you.

What is Knob and Tube Wiring?

Knob and tube (or, K&T) wiring was an early method of electrical wiring used in buildings and homes from the late 1800s up until the 1940s.  The wiring itself consists of two wires, a live wire and a neutral wire.  There is no ground wire.  The phrase “knob and tube” is used to describe this system for it involves insulator “knobs” for isolation and ceramic “tubes” that are used to line holes drilled through wooden studs.

K&T wiring became displaced in time simply because the high costs associated with its installation.  Compared to more modern day wiring technologies, it was also deemed less safe.  Today, new K&T installations are allowed in the U.S. in only very limited situations.  While K&T wiring can still be deemed safe and functional for a home owner, there are several problems with this system.

Concerns and Safety Hazards Associated with Knob and Tube Wiring

In a perfect world, K&T wiring is not inherently dangerous.  But, times have drastically changed since its inception.  In terms of modern day electrical technology, there are some very serious concerns and safety hazards associated with K&T wiring.  These include:

Age and Fire Hazard:  K&T wiring is very old.  At best, a K&T system is at least 60 years old.  In many cases, the simple age of the system means it has likely deteriorated, is cracked, is missing insulation, or can get easily damaged.  Any one of these issues could lead to a fire.

In-line Splices and Fire Hazard:  The wiring methods for a K&T system allowed the use of in-line splices inside walls without the use of a junction box.  This, on its own, poses a fire risk for a mechanical failure of the splice means an uncontained spark inside a wall.

Loose Contacts and Fire Hazard:  Given the age of K&T wiring, tt’s quite possible that the contacts inside the original K&T switches and outlets are loose.  This makes for a poor electrical connection and increases the risk of an electrical fire.

No Ground Wire:  K&T wiring systems consist of two wires – a live and a neutral.  This means there is no ground wire.  With no ground wire, the system cannot service three-pronged appliances.  This may have worked well 60 years ago when household appliances were limited to toasters, irons, and coffee percolators.  But, given today’s vast array of televisions, refrigerators, and other electrical appliances, a grounded electrical system is almost mandatory in a home.

Insurance Difficulties:  Many insurance companies tend to refuse to insure houses that have K&T wiring because of the fire risk the wiring poses.  Several companies will not write a new homeowners policy unless all the K&T wiring is replaced, or an electrician certifies that the wiring is in good condition.

Suggestions for Homeowners with K&T Wiring

Given the very real concerns and safety hazards associated with K&T wiring, the owner of a home with a K&T system, or a potential buyer of a home with a K&T system, is placed in a tough bind.  The big question often asked is: “What am I supposed to do?”  Alpha and Omega Electric has compiled a few important suggestions for you to consider.

  • Have your system evaluated by a qualified electrician.  Only an expert electrician can confirm if your system was installed correctly and whether it has been damaged.
  • Limit the amount of appliances in your home.  An excessive amount of appliances can lead to enhanced fire risks.
  • If any portion of the K&T system is brittle, cracked, or otherwise damaged, contact a qualified electrician to replace that portion.
  • Do not use K&T wiring in certain rooms within your home.  Some of these include: kitchens, bathrooms, and laundry rooms. Wiring must be grounded in order to be used safely in these locations.
  • Consider removing your current K&T wiring and have your home rewired.  Yes, this may pose an expense.  But, unsafe wiring can cause fires and may prevent insurance coverage.


The question as to what one should do with K&T wiring really breaks down into a decision about replacing it with a safer and more current electrical system.  Homeowners and prospective home buyers should carefully consider their options before deciding to rewire a home.  However, an electrical system is just as important for a safe home as a roof, plumbing, or a furnace.  Replacement is often necessary…especially when it impacts the safety of you and your family.

Replacing K&T wiring is just one of the many residential electrical services that Alpha and Omega Electric provides.  If you have any questions about the K&T wiring in your home, contact us today.

Leave feedback
  • Electrical Installs Gallery