Answer: In most cases fiberglass insulation can be placed directly over electrical wires. In the case of true knob and tube wiring, however, where the wire is not coated with a protective covering, you should not insulate over it. We strongly recommend replacing the wiring, or at least having an electrician inspect the existing wiring. Insulation should remain out of the cavities if the old wiring is not replaced.

Another homeowner with a similar question recently sent us the following information from the U.S. Department of Energy website: "If your home was wired using a now obsolete method called knob and tube wiring, the National Electric Code forbids the installation of loose, rolled or foam-in-place insulation if the insulation would surround the wires and prevent heat dissipation from the electrical conductors to a free air space. THIS IS FOR FIRE SAFETY."