I. Introduction
Rewiring a home can be a daunting task, especially when dealing with outdated and potentially dangerous knob and tube wiring. As I embarked on my own rewiring journey, I quickly realized there were many forgotten secrets and tips that could save my life and make the process smoother. In this article, I will share everything I have learned about safely rewiring a home with old knob and tube wiring, from assessing the existing wiring to installing new modern wiring that meets code. My goal is to equip homeowners with the key information they need to rewire their home safely and successfully.
II. Dangers of Knob and Tube Wiring
Before jumping into a rewiring project, it's important to understand why knob and tube wiring is so problematic. This early form of electrical wiring was used in homes up until the 1930s. It features insulated wires that run through ceramic knobs, with tubes protecting the wire where it passes through framing.
While this type of wiring was suitable for small electrical loads when first installed, it can become very dangerous as homes add more lighting, appliances and electronics. Some key problems include:
- Insulation deterioration - the old cloth wiring insulation often breaks down over time, exposing live wires. This can lead to shorts and fires.
- Insufficient grounding - knob and tube wiring has no ground wire, which can result in shocks.
- Overloaded circuits - the wiring is not designed to handle modern electrical loads. This can lead to tripped breakers, dimming lights, damage to appliances and possibly even house fires.
Given these risks, I highly recommend fully rewiring any home with knob and tube wiring. While intimidating, with the right precautions and planning, it can be done safely by a diligent DIYer.
III. Preparing for a Rewiring Project
Before I started ripping open walls, I wanted to make sure I fully understood the scope of the project and had all the necessary supplies. Here are my top tips for preparing for a major rewiring endeavor:
A. Turn Off Power and Inspect Existing Wiring
- Shut off all the circuit breakers or remove the main fuses to ensure the wiring is dead before working.
- Open up outlets and switch boxes to expose the existing wiring and see how it is run.
- Check the condition of the wiring insulation, splices and connections. Document any defects.
B. Plan Your New Circuit Layout
- Decide where you want new outlets, switches and lights located.
- Map out new circuits accounting for 240V appliances like dryer, A/C, etc.
- Ensure you have enough breaker space in the electrical panel. An upgrade may be needed.
C. Purchase All Required Equipment and Materials
- Electrical boxes, conduit, wire, outlets, breakers, junction boxes, and tools
- Safety gear - glasses, gloves, durable footwear, first aid kit
- Warning signs to alert others work is in progress
IV. Removing Knob and Tube Wiring
Once preparations were complete, I was ready to start swapping out the old wiring. This is a slow, meticulous process requiring great care. Here are the key steps I followed:
A. Work on One Circuit at a Time
- Label each circuit at the panel before disconnecting to avoid confusion.
- Disconnect the breaker then verify power is off in the circuit before removing the old wiring.
B. Remove Wiring from Attic First
- Start by removing exposed wiring in the attic to clear the way for new wiring runs.
- Carefully pull out old wiring from joist routes or conduit.
C. Open Walls and Remove Wiring
- Use a voltage tester to double check wires have no power before removal.
- Remove baseboards or ceiling trim to access covered wires.
- Gently pull wires out of walls leaving wiring boxes in place temporarily.
D. Cap Off or Remove Abandoned Wiring
- When removing home runs or entire circuits, cap the wires with wire nuts.
- For fully abandoned wiring, carefully pull all the way back to the service panel and remove.
V. Installing New Wiring
Once the old knob and tube wiring was cleared out, I was ready for the satisfying step of installing safe, modern wiring throughout my home. Here are the key stages I followed:
A. Plan Code Compliant Wiring Routes
- Run wires through drilled holes in joists and studs at least 1.25" back from surface.
- Vertical runs require a drilled hole at least 1.25" away from edges.
- Follow local building codes for wire gauge and outlet spacing requirements.
B. Install New Boxes and Conduit
- Use approved nail guards when strapping boxes to framing to avoid puncturing wires.
- Run flexible conduit between walls and ceilings.
- Use metal conduit for exposed runs along surfaces.
C. Pull and Connect New Wires
- Carefully pull new NM cables through holes and conduit.
- Leave 6-8 inches of slack at each box for connections.
- Use wire nuts to connect hot, neutral and ground wires properly.
D. Install Devices and Covers
- Screw in new outlets, switches and cover plates.
- Attach light fixtures and test them.
- Affix tamper resistant caps to protect unused wiring terminals.
VI. Wrapping Up the Project
Once all the new circuits were installed and tested, there were a few final steps to finish off the project:
A. Update the Service Panel
- Connect the new circuit breakers and verify amperage limits are not exceeded.
- Properly label all new circuits.
B. Patch Walls and Floors
- Seal openings made for wiring with firestop caulk to meet fire code.
- Patch drywall, plaster, flooring and repaint.
C. Test Everything and Make It Look Good
- Turn power back on and methodically test each new circuit.
- Install outlet and switch cover plates.
- Fix any tripped breakers or faulty wiring.
D. Documentation
- Create circuit maps noting all outlet and light locations.
- Save receipts and close out permits.
VII. Conclusion
Rewiring a home with knob and tube wiring was one of the most challenging DIY projects I have undertaken. By educating myself on the risks, creating a good plan, using extreme care, and following codes closely, I was able to successfully rewire my entire home safely. I hope by sharing my experience, I have provided homeowners with the confidence and knowledge needed to tackle rewiring projects themselves. Always prioritize safety, enlist help from an electrician if needed, and be patient - rewiring is a slow and steady process. The end result of having a home protected by modern, robust electrical wiring makes it all worthwhile.