Many old Bay Area homes were wired using a method called “knob and tube,” which was in common use until the 1940’s. You don’t always have to replace it, according to Nick Courcoumelis, owner of Positive Electric, a Diamond Certified company. “Knob and tube can’t be used in places where it can’t supply enough power to a kitchen, bathroom, laundry room or outdoor wiring. Or anywhere you need surge protection because it doesn’t have a ground. However, if it’s in good condition, it can still be used in other parts of the house, like bedrooms.”

Mr. Courcoumelis explains that codes don’t allow electricians to install knob and tube wiring anymore. However, you can insulate over it in California, Read more