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

Introduction

Replacing old knob and tube wiring can be a daunting task, but it is an important safety upgrade for homes built before the 1930s. Knob and tube wiring lacks a ground wire, leaving you vulnerable to electrical fires and shocks. With proper precautions, you can safely upgrade to modern electrical wiring on your own. In this article, I will walk through the complete process of replacing knob and tube wiring, from assessing your existing wiring to installing new circuits. My goal is to provide all the information you need to safely take on this project.

Assessing Your Existing Knob and Tube Wiring

Before beginning any work, it's important to understand exactly what knob and tube wiring you have and where it's located in your home.

Locating All Knob and Tube Circuits

• Carefully examine your electrical panel to identify any circuits labeled with "K&T" or otherwise marked as knob and tube.
• Check along walls, in attics, and in basements for old ceramic knobs and air-insulated wire running through tubes.
• Look for junction boxes and spliced connections between knob and tube and modern wiring. These unsafe connections need to be removed.
• Consult with an electrician if you are unsure whether some wiring is knob and tube. Getting a professional assessment early on will help you develop a clear plan.

Considering the Condition of Existing Wiring

• Evaluate any insulation damage on wires, which can cause shorts.
• Check for modifications to the original wiring like improper splicing. These can be fire hazards.
• Consider having an electrician do a load calculation to see if your old wiring is sufficient for modern appliances.

Mapping Out All Affected Circuits

• With your electrical panel and wiring inspection complete, make a detailed map of which rooms and devices are on knob and tube circuits.
• This will help you plan new circuit routes and ensure you have power where needed during the transition.

Developing a Replacement Wiring Plan

With all the information gathered on your existing wiring, you can now develop a full plan for replacement.

Choosing a Main Approach

You have two main options for how to replace old wiring:

• New wiring alongside old - Run all new wiring through your home without removing the old. Allows you to stage the transition room-by-room.
• Completely replace old with new - Remove knob and tube wiring entirely as you install new circuits. A bigger job upfront.

Consider how comfortable you are doing electrical work, your budget, and the condition of your old wiring when choosing.

Deciding on Circuit Layouts

• Plan circuit routes from the panel through the home with safety and efficiency in mind.
• Follow local codes for required circuits like lighting, receptacles, and appliances.
• Keep high-power circuits separate from low-power ones.
• Include extra capacity for future electrical needs.

Selecting Components like Panel and Wire

• Choose a load center or breaker panel appropriately sized for all your planned circuits.
• Use 12 AWG or 14 AWG copper wire for 15-20 amp branch circuits. Follow codes.
• Pick breakers matched to wire gauge and circuit load. Include AFCI and GFCI protection per code.

Budgeting Time and Costs

• Factor in not just parts but also labor, permits, and special tools or equipment rentals.
• Build in contingencies for unknowns like repairs once walls are opened up.
• Plan for multiple weekends to complete a whole home rewiring.

Safely Working with Live Knob and Tube Wiring

When ready to start your project, safety has to be the top priority when working around live wiring:

Turning Off Power and Verifying

• Turn off the main breaker or fuse disconnecting power to the whole home.
• To verify, plug in and test lights or outlet testers in work areas. All should be dead.
• If any knob and tube wiring remains live, stop and call an electrician immediately.

Wearing Protective Equipment

• Always wear electrical rated gloves and safety glasses when handling wiring.
• Use a non-conductive ladder made of wood or fiberglass if working in the attic.

Being Extra Cautious of Old Wiring

• Treat all original wiring as live until completely removed even if power is off.
• Wires can become crossed and energized without tripping breakers. Better safe than sorry!

Following these critical precautions will help ensure you can work safely around old knob and tube wiring.

Running New Wiring Circuits

Once properly prepared, it’s time to run the new wires that will replace the old:

Routing and Mounting New Wiring

• Plan routing through walls, basement, and attic to follow your circuit map.
• Use non-metallic cable with ground wire for easiest installation.
• Staple cables every 4-6 feet and within 12 inches of boxes per code.
• Leave extra slack at connections to work with easily.

Making Connections

• Use wire nuts to join wires of matching gauge and type.
• Tape connections for additional insulation and security.
• Connect neutral and ground wires properly at each device and junction.

Installing New Devices and Fixtures

• Install new receptacles, switches, lights and other devices along circuit routes.
• Choose tamper-resistant outlets where required by code.
• Use AFCI and GFCI receptacles or breakers to protect circuits.

Labeling All New Wiring

• Clearly label which new breaker powers each circuit at the panel.
• Note circuit routes so they can be identified later behind walls.

Carefully running new, labeled wiring according to code is crucial to the long-term safety and usability of your rewired home.

Removing Original Knob and Tube Wiring

Only once all new wiring is installed should you completely remove hazardous old knob and tube:

Disconnecting Old Wiring at Devices and Panel

• Start by disconnecting old wiring from receptacles, switches, and fixtures.
• Remove any knob and tube breakers or fuses from your panel so wires are dead.

Pulling Old Wiring Out

• Start at one end of a run and carefully pull wiring out of walls or ceiling.
• Coil up wire as you go and use care around fragile knob and tube insulation.
• Check that no wires fall into gaps in walls to create a fire hazard.

Ensuring All Wiring is Removed

• Inspect the full length of old wiring runs to confirm no wire remains.
• Check for any hidden junction boxes still housing live connections.
• Examine walls, attics, and basements closely to spot any missed wires.

Disposing of Wiring Properly

• Coil up old wiring and secure with tape for safe transport.
• Check local regulations on disposal of hazardous electrical wiring.
• Many recycling centers will take old copper wiring to reclaim the metal.

Double check that every last inch of knob and tube wiring is removed and disposed of responsibly. This finishes the job!

Wrapping Up Your Replacement Project

Once all new circuits are energized and old wiring removed, there are just a few final steps to wrap up:

Repairing Walls, Attics, Basements

• Patch any holes or damage from removing old wiring.
• Use plaster, drywall compound, or seals to close up gaps.
• Repair or replace insulation, paneling, and other interior finishes.

Testing All New Circuits

• Turn power back on and methodically test each new circuit at receptacles, lights and switches.
• Verify proper grounding using a multimeter or outlet tester.
• Load test appliances and high-wattage devices on each circuit as well.

Finalizing Permits and Insurance

• Call your local building department for a final inspection on permitted work.
• Inform your insurance company of upgraded electrical service to fix records.
• Keep all invoices and paperwork related to the project in a safe place.

With that, congratulations - you now have a home fully upgraded with modern, safe electrical wiring! I know the process takes patience and care, but the peace of mind and added property value make it well worthwhile.