How to Safely Replace Outdated Knob and Tube Wiring in Your Home

What is Knob and Tube Wiring?

Knob and tube wiring was commonly installed in homes built before 1930. It consists of insulated copper wiring that is run through the open spaces in walls and ceilings, supported by ceramic knobs and tubes.

The wiring is separated from structural framing and exposed to air circulation, reducing fire hazards from heat buildup. However, knob and tube lacks modern safety features like grounding and fire resistant insulation. It also becomes brittle and dangerous as it ages.

Dangers of Outdated Knob and Tube Wiring

There are several risks associated with outdated knob and tube wiring:

Why Knob and Tube Wiring Should Be Replaced

Considering the fire hazards and limitations of knob and tube wiring, experts strongly recommend complete replacement with modern wiring for safety.

Replacing the old wiring enables you to use the full capacity of your electrical system, power sensitive electronics safely, and meet modern building codes. This also makes your home more sellable.

Options for Replacing Knob and Tube Wiring

There are a few options for replacing knob and tube wiring:

Full Rewiring

This involves removing all of the old wiring and installing completely new wiring throughout the house:


The old wiring is left in place but disconnected from circuits. New wiring is spliced to the old and run to outlets and fixtures:

circuit breaker panel replacement

Upgrading the main circuit breaker panel without rewiring the whole house:

Safety Precautions When Replacing Knob and Tube Wiring

Replacing old wiring yourself has dangers if proper precautions aren't taken:

Hiring an Electrician to Replace Knob and Tube Wiring

Consider hiring a licensed electrician if you lack electrical experience or the wiring is very complex. Benefits include:

Get quotes from multiple electricians before selecting one. Check reviews and verify they are properly licensed and insured.


While replacing knob and tube wiring yourself can save money, the safest approach is hiring an electrician, especially if the existing wiring is complex. Pigtailing presents a lower cost alternative to full rewiring. But for peace of mind and full modernization, complete wiring replacement is worth the investment.