Does your home contain knob and tube wiring? If you live in a home built before the 1960s, the answer could be yes. 

From the 1880’s to around the 1950s, homes were wired with what is known as knob and tube wiring. Many older homes today still have remnants of this original wiring. Without tracking down all of the wiring in your home, it may be difficult to determine if your home has any or not.

Dangers of knob and tube wiring

While it was generally safe at the time it was installed, several factors can cause this type of wiring to become dangerous over time.


Age causes the insulation coating around the old copper wires to break down, in many cases exposing bare wire. When carrying an electric load the wire becomes hot and can become a fire hazard. This is especially true if there is insulation or other materials around the wiring. In many cases the old wiring was installed in attic spaces before any insulation. Years later, house insulation may have been added to the attic or crawlspace. If potentially flammable insulation or other materials come into contact with the hot electric wire, a fire can start.

Lack of Ground Wire

Knob and tube wiring is not grounded, which means it is incompatible with modern three-prong plugs and it exposes your family to greater risk of electric shock.

Unsafe Amateur Modifications

In many old homes, over the years, homeowners made their own modifications to their home’s original knob and tube wiring. In most of these cases the homeowner was not a licensed electrician, and the modifications made are intrinsically dangerous, especially with the increased electric load demanded by modern households. In many, many homes with old wiring, there are amateur mistakes lurking, ready to cause a fire when you least expect it.

Updating Your Old Wiring

If your home contains knob and tube wiring, you should have it checked out by a licensed electrician. 

The licensed electricians and OHM Electrical Contracting can help you evaluate whether the old wiring in your home poses a risk to you and your family, and if so, OHM can replace it with safe, modern electrical wiring.

Contact OHM today to get started.