RISKS ARE INCREASING & REPLACEMENTS ARE NEEDED
Currently, the United States National Electrical Code forbids the use of loose, blown-in, or expanding foam insulation over K&T wiring. This is because K&T is designed to let heat dissipate to the surrounding air. As a result, energy efficiency upgrades that involve insulating previously uninsulated walls usually also require replacement of the wiring in affected homes.
As existing K&T wiring gets older, insurance companies may deny coverage due to a perception of increased risk. Several companies will not write new homeowners policies at all unless all K&T wiring is replaced, or an electrician certifies that the wiring is in good condition. Also, many institutional lenders are unwilling to finance a home with the relatively low-capacity service typical of K&T wiring, unless the electrical service is upgraded.
SAFETY HAZARDS OF KNOB & TUBE WIRING
Lack of Capacity
Modern home buyers often find that existing K&T systems lack the capacity for today’s levels of power use.
Heat Damage or Fire
Overusing of the circuits subjects wiring to higher levels of current and risks heat damage or fire.
Dry and Brittle Insulation
Knob-and-tube wiring may also be damaged by building renovations. Its cloth and rubber insulation can dry out and turn brittle.