Many insurance companies will no longer insure knob and tube wiring. Those that do tend to charge much higher premiums. In my view, often the biggest problem with knob and tube has less to do with the original wiring than the way people have butchered it over the years. For example, in the photo below, someone has cut into it in an attic. They have then spliced into the circuit yet another wire. This wire, and this is important, is lighter gauge (smaller) than the knob and tube circuit. So the potential problems are many: Old knob and tube to begin with; splices made outside of a proper junction box; a wire spliced in that is too small and is likely to overheat. When an inspector sees wiring like this, he or she had better refer it on to an electrician.
Thanks for stopping by.
Steven L. Smith