Knob and tube wiring was commonly installed in homes built before the 1950s. While it served its purpose at the time, this outdated wiring can be a safety hazard and doesn't meet modern electrical codes. Fortunately, there are ways to replace knob and tube wiring in your home without the expense and mess of rewiring the entire house.
Understanding Knob and Tube Wiring
Knob and tube wiring consists of individual wires that are separated by ceramic knobs and run through porcelain tubes. Unlike modern wiring that is bundled together in a protective sheath, knob and tube wires are more exposed and prone to damage. Other issues include:
- Overloaded circuits: Knob and tube wiring was designed for smaller electrical loads. Connecting modern high-wattage appliances can be a fire hazard.
- Insulation breakdown: The old cloth or rubber insulation can become brittle and crack over time. This leads to shorts and shock hazards.
- Exposed splices: Connections between wires are often exposed and poorly secured. This creates additional failure points.
While functional when first installed, knob and tube wiring is outdated and dangerous by modern standards. Replacing it should be a top priority for homeowners.
Why Rewiring the Whole House Isn't Necessary
Rewiring an entire house with knob and tube wiring can cost tens of thousands of dollars. The good news is that you likely don't need to replace all of the old wiring to make your home safer. Here are some key points:
- Prioritize high-use circuits: Focus on replacing wiring for kitchen, laundry, and bathroom circuits first. These areas have the highest electrical load.
- Tap into existing wires: In many cases, you can fish new wires alongside old and tap into existing circuits. This avoids major demolition.
- Upgrade section by section: Take a gradual room-by-room approach to spread out costs over time.
- Meet insurance requirements: Many policies only require that you replace a certain percentage of knob and tube wiring.
Strategically upgrading circuits and sections of the house allows you to realize the benefits of modern wiring without prohibitive costs.
Step-by-Step Guide to Replacing Knob and Tube Wiring
Replacing knob and tube wiring yourself is an advanced DIY project, but can yield major cost savings compared to hiring an electrician. Follow these key steps to safely upgrade old wiring in your home:
1. Turn Off Power and Inspect Existing Wiring
- Shut off power at the main panel before doing any work
- Locate all knob and tube wiring and identify any damage
- Check connections to electrical boxes and junction points
2. Map Out New Wiring Route
- Plan pathway to run new wiring to lights, switches and outlets
- Look for routes through basement, crawlspace or along walls
- Choose path that avoids major demolition or alterations
3. Install New Wiring and Electrical Boxes
- Run wires through planned route and secure with staples
- Install new plastic electrical boxes to replace old braced knob and tube boxes
- Connect new wiring to boxes and devices
4. Connect New Wiring to Panel
- Turn off main breaker and connect new wiring to circuits
- Properly label new circuits in the panel
- Cap off and disconnect any old knob and tube wiring that's still live
5. Patch and Repair Surfaces
- Seal up any holes or chases with plaster, sealant or drywall
- Refinish surfaces to match existing walls and ceilings
- Check for functionality and turn power back on
Consult an Electrician for Major Projects
While DIY replacement is possible in many cases, it's best to hire a licensed electrician for large scale projects or if you don't feel comfortable doing the work yourself. A qualified electrician can:
- Navigate complex wiring systems safely
- Ensure proper installation of new wiring and boxes
- Obtain necessary permits for major upgrades
- Provide guidance on prioritizing which circuits to replace
Don't take risks with complex electrical work. An investment in a professional electrician is worthwhile for your safety.
Make Your Home Safer by Replacing Outdated Wiring
Knob and tube wiring served its purpose in the past, but lacks the safety and capacity of modern electrical systems. Targeted upgrades allow you to reap the benefits of safer and higher capacity wiring without the cost and work of rewiring your entire home. With proper planning and safe installation practices, you can proactively eliminate the fire and shock risks of old knob and tube wiring.