Knob and tube wiring was commonly installed in homes built before 1950. While this type of wiring was suitable for the electrical demands at the time, it can become faulty and dangerous as it ages. Replacing the entire electrical system is expensive and time-consuming. Fortunately, there are ways to fix faulty knob and tube wiring without a full replacement.
Assessing the Damage
The first step is to thoroughly assess the extent of the damage to determine what needs to be fixed. I inspect each room carefully, looking for:
Exposed or frayed wiring - This poses a fire hazard and needs to be addressed immediately.
Faulty connections - Loose connections can cause arcing and sparks. I tighten or replace outlets, switches and junction boxes as needed.
Insulation breakdown - The insulation around knob and tube wires becomes brittle over time. Any cracks or damage in the insulation can lead to shorts.
Overloaded circuits - Older wiring may not be adequate for handling modern electrical loads. I check for tripped breakers, blown fuses, flickering lights etc.
For minor issues, some quick fixes can improve safety without replacing the entire system:
Replace Faulty Outlets and Switches
- I replace any outlets or switches that are worn out, damaged or sparking. Modern replacements are safer and more reliable.
Upgrade the Electrical Panel
- Upgrading to a modern breaker panel provides extra capacity and safety shut-off if circuits are overloaded.
Add GFCI Outlets
- GFCI (ground fault circuit interrupter) outlets provide protection from shocks. I have these installed in kitchens, bathrooms and other high-risk areas.
Remove Unsafe Wiring
- I remove any knob and tube wiring that is damaged beyond repair. The circuit can be rerouted through modern wiring.
For more extensive issues, I perform targeted segmental replacements:
Prioritize High-Risk Areas
- I focus on replacing wiring in kitchens, bathrooms and other areas where there is risk of water contact or where major appliances are used.
Replace with Modern Wiring
- I reroute the circuit using modern NM (nonmetallic) cable with grounding. This segmented approach is cheaper than rewiring the entire home.
Update One Circuit at a Time
- To manage costs, I rewire one problematic circuit at a time. This minimizes disruption to the household.
When making repairs, I take precautions to work safely:
I turn off power at the main panel before working.
I check wires with a non-contact tester before touching to confirm power is off.
I wear electrical gloves and avoid working alone.
For large jobs, I obtain the necessary electrical permits from the city.
When Full Replacement is Needed
In some cases, the knob and tube wiring is too far gone and a full electrical system replacement is required. Some signs this is needed:
Majority of circuits are damaged or faulty
Entire sections of wiring need to be accessed behind walls
Load capacity is inadequate for modern usage
Insurance company mandates rewiring for continued coverage
While expensive, a full rewiring provides peace of mind that your electrical system is completely safe and meets modern codes.
With proper assessment and targeted repairs, you can extend the life of aging knob and tube wiring. Segmental upgrades and safety improvements allow you to avoid the major expense and disruption of rewiring your entire home. However, if the system is too far gone, a full replacement may be required. With the right approach, you can keep your home safe without breaking the bank.