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

Knob and tube wiring was commonly installed in homes built before the 1940s. While it served its purpose at the time, this old wiring system can be dangerous by today's electrical standards. Replacing knob and tube wiring with modern electrical wiring improves safety and allows your home's electrical system to handle more power. I recently went through the process of removing the outdated knob and tube wiring in my century home. Here's how I did it safely and up to code.

Dangers of Knob and Tube Wiring

Knob and tube wiring consists of individual wires that are separated by ceramic knobs and run through tubes or conduits. While this system was sufficient for small electrical loads when first installed, it has some major drawbacks:

Fire Hazard

Insufficient for Today's Power Needs

No Grounding

While I was initially hesitant to take on such a major project, the risks of keeping the outdated wiring convinced me it was time for an upgrade.

Planning the Wiring Replacement Project

Replacing knob and tube wiring in an entire house is a major undertaking that requires planning and preparation. Here are key steps I took to plan out my wiring project:

Consult an Electrician

Consider a Phased Approach

Apply for Electrical Permits

Choose a Rewiring Method

Research and Hire a Licensed Electrician

Safely Removing Knob and Tube Wiring

Once I had planned out the project, it was time to remove the outdated wiring. Safety was my top concern during this process:

Turn Off Power at Main Panel

Wear Protective Gear

Check Wires Before Cutting

Remove Wiring Carefully

Dispose of Wiring Properly

Paying close attention to safety resulted in the knob and tube wiring being removed from my home without incident.

Installing New Electrical Wiring

With the old wiring gone, the electrician could install the new wiring system:

Lay Out Wiring Plan

Run Wires

Install Junction Boxes

Connect Grounds

Attach Outlets and Switches

Connect Devices

Add Circuit Breakers

The electrician handled all of the new wiring installation professionally while communicating each step. In total, the rewiring took about two weeks.

Wrapping Up the Wiring Replacement Project

Once the new electrical system was in place, there were a few final steps to finish the rewiring project:

Testing and Inspections

Patch and Repair Walls

Add Electrical Labels

Clean Up Work Areas


Replacing knob and tube wiring was a major undertaking, but I now have complete peace of mind knowing my home's electrical system is safe and up to modern standards.