How to Safely Replace Knob and Tube Wiring in Old Homes

How to Safely Replace Knob and Tube Wiring in Old Homes


Replacing old knob and tube wiring in your home can seem like a daunting task, but with proper planning and safety precautions, it can be done safely by a homeowner. Knob and tube wiring was commonly installed in homes built before 1950 and lacks many of the safety features of modern electrical systems. Upgrading to modern wiring brings your home up to current code and reduces fire risks. In this guide, I'll walk you through the complete process of replacing knob and tube wiring in an old home.

Dangers of Knob and Tube Wiring

Before starting any electrical project, it's important to understand why knob and tube wiring can be dangerous:

Replacing knob and tube wiring eliminates these risks and brings the home up to modern safety standards.

Planning the Replacement Project

Careful planning is crucial when taking on an electrical project. Follow these planning steps before touching any wiring:

Consult an Electrician

Research Permit Requirements

Create a Wiring Diagram

Label Circuit Breakers

Purchase Supplies

Safety Tips for the Project

When dealing with electrical wiring, safety should be your top concern. Follow these precautions:

Turn Off Power at the Breaker

Work on One Circuit at a Time

Wear Protective Equipment

Use a Voltage Tester

Check for Hidden Knob and Tube

Step-by-Step Replacement Process

With proper planning and safety preparations completed, you're ready to replace the old wiring. Follow these key steps:

1. Disconnect Knob and Tube at Outlets and Junctions

2. Run New Wiring to Each Box

3. Connect New Wiring at Service Panel

4. Connect New Wiring at Outlets and Junctions

5. Label New Circuits

6. Update Permit and Electrical Inspection

Once approved, turn the main power back on and test all outlets to ensure proper function. With the old knob and tube fully replaced, you can rest easy knowing your home's electrical system is safe and meets modern code. Be sure to take precautions anytime electrical work is needed in the future.

Common Questions about Replacing Knob and Tube Wiring

Is it required to replace knob and tube wiring?

Can I just abandon knob and tube wiring in place?

How difficult is it for a homeowner to replace wiring?

Does all wiring need to be replaced at once?

How much does a full rewiring job typically cost?


While rewiring an old home takes time and diligence, it greatly improves home safety and functionality. By planning the project thoroughly, remembering crucial safety steps, and methodically replacing the old wiring, a homeowner can successfully convert their electrical system from hazardous knob and tube to modern code-compliant wiring. Proper electrical wiring ensures safe operation of modern lights and appliances.