How to Safely Rewire Your Home Using Knob and Tube Wiring

How to Safely Rewire Your Home Using Knob and Tube Wiring


Knob and tube wiring was commonly installed in homes up until the 1940s. This old wiring system can be unsafe due to degradation over time. However, with proper precautions, I can safely rewire my home while leaving the existing knob and tube intact. Here is a comprehensive guide on how I plan to safely rewire my home while utilizing the existing knob and tube wiring.

Dangers of Knob and Tube Wiring

Knob and tube wiring has several inherent dangers that I need to be aware of:

To mitigate these risks, I need to take the proper precautions when rewiring around old knob and tube wiring.

Pre-Rewire Inspection

Before beginning any rewiring project, I need to thoroughly inspect the existing knob and tube wiring:

Any unsafe wiring I find will need to be replaced with modern NM cable before rewiring the rest of the home.

Install New Grounding System

Since knob and tube wiring has no ground wire, I need to install a new grounding system to lower shock risks:

Properly grounding the system is crucial for safety. I may also need to install GFCI outlets in ungrounded areas for additional protection.

Running New Wiring

When running new NM cables, I need to take care to avoid contacting or damaging any existing knob and tube wiring:

Taking it slow and checking my work is key to preventing damage to old wiring during new installations.

Connecting New Wiring to Old Systems

I need to be extremely cautious when connecting new wiring to existing knob and tube circuits:

Rushed or improper connections can lead to dangerous shorts and fires. Meticulous work is essential.

Inspecting My Work

Once the rewiring is complete, I need to thoroughly inspect all of my work:

Taking the time to methodically inspect all my work allows me to identify and correct any potential hazards introduced during the rewiring process.


Rewiring a home while preserving old knob and tube wiring can be done safely, but requires great care in planning, installation, and inspection. With proper precautions, the inherent risks of knob and tube can be mitigated. Patience and meticulous work practices are essential to preventing electrical hazards. When in doubt, I should consult with a licensed electrician. But by following this comprehensive guide, I can rewire my home while protecting the original knob and tube system.