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

Introduction

Replacing the old knob and tube wiring in your home can seem like a daunting task, but it is important for safety and functionality. This type of wiring was used in homes built before the 1930s and can pose fire and shock hazards if left in place. With proper planning and precautions, I was able to completely rewire my home. Here is an overview of the process I used to remove the old wiring and install new electrical wiring in my house.

Dangers of Knob and Tube Wiring

Before starting any work, it's important to understand why knob and tube wiring needs to be replaced. This old wiring has paper insulation on the wires rather than plastic or rubber. Over time, the insulation becomes brittle and cracks, exposing the inner conductor. This can allow wires to arc or spark, creating a fire hazard.

The wires are also not grounded, meaning there is an increased risk of shock if one of the wires becomes damaged. If appliances aren't grounded properly, a shock can occur.

Other issues include:

• Insufficient circuit capacity for modern power demands
• Lack of safety devices like overcurrent protection
• Wiring running through unsafe materials like lath and plaster

Replacing this outdated wiring eliminates these risks and allows your home's electrical system to function safely and effectively.

Planning the Rewiring Project

Before getting started, carefully plan the project to make sure it goes smoothly:

• Consult an electrician - Unless you are very experienced, have an electrician provide guidance. They can identify any issues and provide repair estimates.

• Check with local permit office - Most areas require permits for rewiring projects. Make sure to get proper permits.

• Have professionals do major electrical work - Hire an electrician to remove main fuses/breakers, install new service panel, etc.

• ** Map out the existing wiring** - Diagram where all the knob and tube wiring runs, including the locations of outlets and fixtures.

• Decide what to keep vs. replace - You may be able to keep some newer wiring. The electrician can determine what needs to go.

• Develop a plan for the new wiring - Include things like new outlet, switch, and lighting locations.

• Calculate how much wire you need - Measure lengths and purchase enough new NM electrical wire with ground for the project.

Removing Old Knob and Tube Wiring

Once the prep work is complete, it's time to remove the outdated wiring. This involves carefully taking it out section-by-section:

• Turn off power at the main panel - The electrician should cut the main circuit breakers/fuses so there is no live power.

• Remove switches and outlets - Take out all electrical boxes, switches, receptacles, and fixtures on the old wiring.

• Take down any accessible wiring - Carefully pull out knob and tube wiring that is visible or easily reachable.

• Cut wiring in walls - For buried wiring, cut it into sections in accessible areas like the attic or basement.

• Cap ends - Cap any remaining dead ends so wires are not exposed.

• Scrape off knob hardware - Thoroughly remove any knob brackets or tubes remaining.

• Patch walls and ceilings - Repair any holes or damage from removing the old wiring.

Running New Wiring

The fun part is finally installing fresh new electrical wiring throughout your home:

• String the new wires - Run the new NM cables along planned routes between outlets, switches and electrical boxes.

• Install junction boxes - Put in any necessary junction boxes where wiring runs join together.

• Mount the devices - Securely mount receptacles, switches, and other electrical devices.

• Connect devices properly - Use wire nuts to connect wires correctly based on diagrams. Double check connections.

• Ground the system - Connect the ground wire in all boxes and devices. This provides crucial safety.

• Label the circuits - Label each wire with the corresponding circuit number so they are identifiable.

• Check circuits - Test each run to make sure circuits are properly connected and functioning.

Finishing Touches

Once the new wires are run, installed, and tested, put things back together:

• Insulate wires - Seal any wire holes or gaps with caulk and insulation to prevent drafts or pests.

• Install covers and fixtures - Put light fixtures, switch plates, outlet covers, and anything else removed back in place.

• Add safety devices - Install smoke detectors, GFCIs, and AFCIs according to code requirements.

• Have the electrician hook things up - Have the main service panel reconnected and check that everything is working properly.

• Complete final inspection - Contact the local building department to set up a final inspection once the project is complete.

Conclusion

While rewiring an entire home is no small task, it can be done successfully with proper planning and care. The peace of mind and increased home safety after replacing outdated knob and tube wiring is well worth the effort. Just be sure to educate yourself on the process fully and consult electrical experts so the project goes smoothly from start to finish. Your home will be much safer with a modernized electrical system.