How to Replace an Old Knob and Tube Wiring System

How to Replace an Old Knob and Tube Wiring System


Replacing an old knob and tube wiring system in your home can seem like a daunting task, but it is doable with proper planning and precautions. As someone who has gone through this process myself, I will provide a step-by-step guide to walk you through the entire project from start to finish.

Reasons for Replacement

There are several good reasons to replace knob and tube wiring:

Replacing the old wiring now can prevent problems down the road and make your home safer and more valuable.


Proper planning and preparation will make the wiring replacement job go smoothly. Here are some key steps to take before starting:

Advance planning and preparation will pay off during the wiring replacement process.

Hiring an Electrician

The most important step in replacing knob and tube wiring is to hire a qualified, licensed electrician. This is not a DIY project for an amateur.

When hiring an electrician, be sure to:

A master electrician or licensed electrical contractor will ensure the wiring job is done properly and passes inspection. Don't risk safety - hire a pro!

Electrical Permit

Once you have an electrician lined up for the project, they can help you obtain the proper permit from your local building department.

The permit application will likely require:

There will be a fee for the electrical permit, which varies by location. The permit process ensures your rewiring project follows all codes and regulations. Your electrician can handle this permitting process for you.

Rerouting Electrical Lines

With permits in place, the hands-on work of replacing the old wiring can begin. The general process will involve:

Your electrician will take care of rerouting all the necessary electrical lines throughout the house during the rewiring.

Inspection & Sign Off

Once the new electrical system is installed, the local building inspector must come out and approve the new wiring and connections before the walls get closed up.

The inspector will check for:

It's common for minor issues or changes to be needed after the inspection. Your electrician will make any corrections, and have the inspector return to sign off on the project. This final approval is important documentation and assures a safely rewired home.

Restoring & Cleaning Up

After the inspector signs off, your electrician can button up the rewiring job by:

Restoring surfaces and cleaning up properly after all the rewiring work is completed will allow you to settle back into your home without any lingering mess or damage.


While rewiring an older home with knob and tube is a major undertaking, having it done by qualified electricians will make the process go as smoothly as possible. Proper planning on the front end, careful installation work, getting necessary inspections, and thorough cleanup at the end are all key to successfully replacing that outdated, hazardous old wiring. The investment of time and money is well worth it for the safety and value it adds to your home. I hope this outline gives you a clearer picture of what to expect during a full electrical rewiring project. Let me know if you have any other questions!