How to Safely Replace Your Home's Knob and Tube Wiring

Introduction

Replacing old knob and tube wiring in your home can significantly reduce your fire risk and allow you to upgrade to modern electrical capacity. However, working with electrical systems can be extremely dangerous if proper precautions are not taken. In this guide, I will walk through the complete process of safely replacing knob and tube wiring, from assessing your existing system to hiring a licensed electrician for the replacement work.

Assessing Your Existing Knob and Tube Wiring

The first step is to understand exactly what kind of knob and tube wiring you have in your home. This old wiring system was phased out in the 1930s, but may still be present in older homes. Here's what to look for:

• Knobs - These are porcelain spacers attached to framing that hold the wiring in place. They are typically found in attics or crawlspaces.

• Tubes - Insulated tubes protect wires where they pass through walls, floors, and framing.

• Cloth-wrapped wiring - Early knob and tube wires were cloth-wrapped around copper conductors, unlike modern plastic-insulated wires.

• Fuses - Pre-1930s electrical panels likely have glass cartridge or screw-in fuses instead of circuit breakers.

• Insulation concerns - Knob and tube wires may be dangerously close to insulation added after initial construction.

Thoroughly inspect your attic, basement, crawlspaces, and garage for these signs of old wiring. Check inside walls by removing electrical covers if possible. Consult an electrician if you are unsure about any observed wiring.

Dangers and Limitations of Knob and Tube Wiring

Once you have confirmed knob and tube wiring exists in your home, it's important to understand the potential hazards and limitations:

• Fire risk - The old, brittle insulation can crack and expose live wires to flammable materials. This causes electrical arcing and heat generation.

• Lack of grounding - Knob and tube has no equipment grounding conductor, increasing the risk of shocks.

• Insufficient capacity - These systems were designed for lights and basic appliances, not modern loads.

• Insurance issues - Many insurers won't issue policies for homes with knob and tube wiring due to fire concerns.

Replacing knob and tube wiring throughout your home is the only way to fully address these risks. Piecemeal repairs or extensions from the old system are not recommended.

Hiring a Licensed Electrician

Electrical work should only be performed by a licensed electrician, as there is a real risk of injury, fire, or even death if wiring is handled improperly.

When hiring an electrician:

• Verify their license with your state licensing board.

• Check reviews and ask for references from past customers.

• Get multiple quotes to compare costs.

• Confirm they carry insurance including liability and workers compensation.

• Get a detailed written quote outlining the full scope of work.

A quality electrician will also pull any required permits and schedule inspections of the work by your local building department.

Overview of the Replacement Process

Replacing knob and tube wiring involves either running all-new wiring or, in some cases, installing new wires alongside the old. Here is a basic overview:

• The old wiring system is visually traced to determine the extent and routing.

• Proposed new wiring routes are planned based on your home's layout and accessibility.

• Approved electrical panels, junction boxes, and other components are installed.

• Existing knob and tube wires are disconnected at both ends. They should not be reused.

• New copper wires are run through walls, ceilings, and framing following proper codes.

• Lights, switches, receptacles, and appliances are connected to the new wiring system.

• A final inspection confirms safety before the new system is activated.

The scope of work will vary considerably based on your home's design. A farmhouse may require complete rewiring, while a newer home may only need minor upgrades.

Key Safety Precautions During the Replacement Process

Your electrician should follow a number of important safety precautions while replacing knob and tube wiring:

• Turn off power at the main breaker before starting any work. Verify it is off!

• Test wires before handling to confirm they are de-energized.

• Wear personal protective equipment like non-conductive gloves and eye protection.

• Isolate wires with electrical tape as they are removed to prevent accidental contact.

• Handle wiring gently - don't pinch or bend wires at sharp angles.

• Keep flammable materials away from work areas with exposed wiring.

• Check behind walls before cutting to avoid buried wires.

• Follow codes for proper wire types, sizing, routing, connections, and more.

Your home's safety depends on careful, professional electrical work. Don't attempt DIY wiring projects unless you are absolutely certain you have the training and experience to do so safely.

Completing the Project and Wrapping Up

Once the new wiring system is installed throughout your home, the outlets, lights, and appliances can be connected. At this point, your electrician will:

• Perform a series of safety tests, checking for continuity, polarity, and grounding.

• Schedule a final inspection by your local building department.

• Complete any needed fixes to pass the final inspection.

• Remove old wiring if it will be abandoned in place, clipping it flush with walls.

• Clean up debris and repair any necessary drywall or finishes.

• Provide documentation like updated electrical drawings of your home.

With your new, modern wiring system in place, you'll gain safety, capacity, and enjoy reduced electrical fire risks. Just be sure to get the required permits and inspections to stay compliant with local codes. You'll likely need to notify your insurance company as well.

While the process can seem daunting, replacing knob and tube wiring is a smart investment for your home's safety and functionality. By following the guidelines I've outlined and hiring a professional electrician, you can complete the project smoothly and safely. Let me know if you have any other questions!