Knob and Tube is a wiring method that was used in homes in the early 1900s to 1940s and is no longer used. These older electrical systems do not have the same safety benefits as modern ones. For example, ground fault circuit interrupters make wet locations like bathrooms and outdoor locations safer. It may surprise you that many insurers will not provide or renew coverage on homes with this type of wiring. They consider it to be a higher risk. Some insurers may make you replace the knob and tube