How to Replace an Old Knob and Tube Wiring System

Introduction

Replacing an old knob and tube wiring system in your home can seem like a daunting task, but it is doable as a DIY project if you take the proper safety precautions. Knob and tube wiring was commonly installed in homes built before 1950 and is outdated and potentially unsafe compared to modern electrical systems. Upgrading allows you to enjoy the safety and convenience of modern power distribution. In this article, I will walk through all the key steps involved in replacing knob and tube wiring in a safe and effective manner.

Reasons to Replace Knob and Tube Wiring

There are several important reasons why you should strongly consider replacing knob and tube wiring:

Fire hazard - The old, brittle wire insulation often cracks over time, exposing the conductors and increasing fire risk. Knob and tube lacks grounding which can also be hazardous.
Insufficient for modern loads - Knob and tube was designed for simple, low-wattage electrical loads. Most modern homes have much greater power demands.
Difficult to extend or modify - It can be challenging to add new circuits or modify existing ones without damaging the fragile wiring.
Insurance issues - Many insurers won't cover homes with old systems or charge substantially higher premiums.
Resale value - Upgrading wiring makes your home more attractive if you ever plan to sell.

Replacing this obsolete system with modern wiring addresses these risks and limitations. The peace of mind and added safety are well worth the effort.

Preparing for a Knob and Tube Replacement Project

Careful planning and preparation will ensure your wiring project goes smoothly:

Have an electrician inspect first - A pro can assess the scope of the job and provide a cost estimate. They can also handle any tricky parts of the job.
Check permits and regulations - Most areas require permits for electrical work. Research local requirements.
Turn off power at the main panel - Switch the main breaker off before working.
Inventory supplies needed - Have wire, junction boxes, conduit, tools, and safety gear ready.
Clear access paths - Remove any insulation or other obstructions blocking access.
Take photos before dismantling - Document original wiring runs before altering anything.
Have a temporary power plan - Consider a generator so you can still run essentials like the fridge.

Proper planning makes a wiring project far less stressful.

Step-by-Step Guide to Replacing Knob and Tube Wiring

With adequate preparation, the process for replacing old wiring is straightforward:

Disconnect and Remove the Old System

Turn off power at the main breaker panel and verify it's off.
Disconnect any live circuits you need to keep using.
Detach wires from outlets, switches and appliances.
Unscrew or clip off ceramic knobs.
Pull the wiring out from the walls, ceiling and crawlspaces.
Caution: Live wires can still exist even when power is off. Work carefully.

Removing all the obsolete wiring is the first essential step before installing the new system.

Install New Wiring and Components

Run cables through walls and ceilings. Follow local codes for proper gauge wire.
Fish wires into boxes for outlets, switches and fixtures. Leave extra slack.
Connect wires securely using wire nuts. Wrap connections with electrical tape.
Attach cables to junction boxes and hangers with proper cable clamps.
Screw receptacles, switches and cover plates onto boxes.
Connect fixtures like lights and fans to the new wiring.
Install a main service panel if needed. Run wire to hook up.
Connect ground wires and ensure proper bonding.

Take care to follow codes and best practices for safe new wiring.

Connect the New System and Restore Power

Attach new wire runs to the main circuit breaker panel.
Ensure all unused old wiring is removed from the panel.
Verify all connections are tight and insulated properly.
Check that grounding is adequate and meets codes.
Have repairs inspected and approved before turning power back on.
Restore electricity gradually at the main panel.
Test all lighting, outlets, and appliances.

With power restored, you can relax knowing your home's electrical system is completely modernized and safe.

Final Considerations

Replacing knob and tube wiring is a major project, but the benefits for your home's safety and functionality are immense. To recap key tips:

Hire a professional electrician if you lack expertise.
Follow all permitting and inspection requirements.
Never compromise on safety gear and procedures.
Take the necessary time to do a careful, complete job.
Ask an electrician if you have any doubts during the project.

While upgrading old wiring requires effort, you will gain invaluable peace of mind knowing your home's electrical system is as modern and safe as possible.