Electricians no longer use the knob and tube method to wire houses, and it's widely believed to pose a hidden risk to homeowners. So, is knob and tube wiring safe or do you need to hire a professional to rip out and replace your existing system? We are the professional services provider. Knob and tube wiring gets its name from the ceramic knobs used to hold wires in place and ceramic tubes that act as protective casings for wires running through wall studs or floor joists. Instead of the three wires found in modern electrical installations, knob and tube wiring has only two — a black (hot) wire and a white (neutral) wire. This means there is no ground wire in the system for excess charge or in the event of a short.