The legality of knob-and-tube wiring in a house under the 2020 NEC (National Electrical Code) depends on a few factors: Grandfathering

If the knob-and-tube wiring was legally installed according to the electrical code in effect at the time of installation, it is generally grandfathered in. This means it's allowed to remain as long as it's in good condition and safe.

Local Codes

Local jurisdictions (cities, counties, etc.) can have amendments to the NEC or their own electrical codes that are stricter than the NEC. Some jurisdictions may require knob-and-tube to be removed or upgraded when a house is sold, renovated, or if it presents a safety hazard.

Safety

Regardless of whether it's grandfathered in, if the knob-and-tube wiring is damaged, deteriorated, or presents a safety hazard, it must be repaired or replaced.

Insulation

The NEC prohibits covering knob-and-tube wiring with insulation. This is because knob-and-tube relies on free air circulation to dissipate heat. Covering it with insulation can cause the wires to overheat and become a fire hazard.

Therefore, based on the NEC 2020, knob and tube is generally legal if grandfathered in and not covered by insulation.Important Considerations



Insurance

Many insurance companies are hesitant to insure homes with knob-and-tube wiring, even if it's in good condition. You may have difficulty obtaining insurance or may pay a higher premium.

Safety Inspection

It's highly recommended to have a qualified electrician inspect any knob-and-tube wiring to assess its condition and safety.*

Upgrading

Even if the knob-and-tube is in good condition, upgrading to modern wiring is generally recommended for safety and to increase the electrical capacity of your home.

In summary, while knob-and-tube wiring may be legal in some situations, it's crucial to check with your local building department and a qualified electrician to determine the specific requirements in your area and to ensure the safety of your home. Flag for review