Knob and tube wiring is an older electrical system that was commonly used in homes built before the 1950s. It consists of ceramic knobs that support wires and ceramic tubes that protect wires as they pass through studs and joists. If you're considering a home with knob and tube wiring, there are some important things to look for, as this type of wiring can be a potential fire hazard and may not meet current electrical codes. Here are some key factors to consider:

Age of the system: The age of the knob and tube wiring system is an important factor to consider. If the wiring is original to the home and has not been updated, it may be more than 70 years old, which can increase the likelihood of wear and damage to the wiring.

Condition of the wiring: It's important to inspect the condition of the wiring to determine if it has been compromised, such as by being nicked, frayed or exposed. Knob and tube wiring may also be brittle or disintegrate over time. If the wiring is in poor condition, it may need to be replaced.

Knob and Tube Wiring


Type of insulation: Knob and tube wiring typically has no ground wire and is insulated with rubber or cloth. This type of insulation can deteriorate over time and become brittle, potentially causing electrical arcing, sparking or shorting.

Presence of modifications or additions: If modifications or additions have been made to the electrical system, it's important to determine if they were done properly and to code. Older homes may have had el

ectrical work done by previous owners that was not up to code or may have used improper methods or materials.

Safety features: Look for any safety features that have been added to the knob and tube wiring system, such as a grounded outlet or GFCI protection. These features can help reduce the risk of fire or electrical shock.

Overall, knob and tube wiring can be a potential safety hazard and may need to be replaced or updated to meet current electrical codes. It's important to have a professional electrician inspect the system and make recommendations for repairs or replacement if necessary.