Proper maintenance is key. The porcelain tubes pass through beams, rafters, and walls, and porcelain knobs are used to carry the wire around corners. At times, homeowners with this older wiring can find it difficult to obtain insurance on such homes because some insurance companies are skittish about taking on a house they perceive as risky.
Many insurers require an inspection to show that the coating on the wiring is in good condition.
If it is, they may write you a policy. Because older houses often have a lower capacity in their wiring systems, homeowners should make sure they don't have too many electrical gadgets plugged in, such as computers, stereos, and so forth. An electrical overload could easily result in a fire. Knob and tube wiring may continue to be safe to use. Proper maintenance is the key.