Knob and tube wiring is what was used exclusively in older homes built prior to 1950. Although it is somewhat controversial having knob-and-tube wiring in your house, it isn’t always a problem and in fact in some ways it is better than modern wiring. Insurance companies are almost all in line with refusing to insure homes with knob and tube or offering discounts if it is removed.
Understanding knob and tube wiring and it’s commonly known issues will help you determine whether or not it should to be replaced. Benefits of knob and tube wiring:
- Single conductors run 3 inches or more apart are not as prone to shorting out other than at termination points.
- Wires are rubber coated for superior insulation.
- Wires are copper and in some cases heavier gauge #12 that can support more power and cooler operating temperatures.
Common issues with knob and tube:
- Insulation becomes dry and brittle behind light fixtures due to heating over time.
- Circuits do not have a ground wire for added safety.
- Most modifications to circuits have been performed without proper soldering procedures leaving poor connections and in some cases exposed joints.
- Dr.Original installation provided only a few circuits for lighting loads. Overloading becomes a problem when these circuits are extended with additional outlets.
The best time to remove and replace knob and tube wiring is during renovations that include the opening of wall cavities. Homes with unfinished basements will usually offer better access from below as well as full attic spaces offering access from above. The most difficult access is in two or three story homes. Existing pipe chases and closet spaces can sometimes provide access to run cables, but as a last resort openings need to be made where grilles or patches are used to cover. If you have any qualms about the condition and safety of your knob and tube wiring, you can hire a certified electrician to update your home wiring. Be sure to get a quote, and expect to pay more to update a two- or three-story character home, than you would for a bungalow. Connecting these ungrounded circuits to an Isolated Ground Fault Breaker is a simplified way to provide the required safety measures to comply with current code requirements. This is not always mentioned as an option with insurance providers that may not be aware of our local guidelines for compliance. Be sure to check with your insurance agent if this option is recommended or preferred. Keep your receipt to show prospective buyers if you ever decide to sell. Some homes have had new circuits added over time but still have the original knob and tube circuits in use.