Knob and Tube Wiring Knob and tube wiring is usually found in homes built more than 50 years ago, and in some cases, was even used in the 1960s and 1970s. Knob and tube gets its name from the insulator knobs used to keep the wires isolated from objects and the ceramic tubes used to line holes through wooden floor joists. It is usually found with older 60 amp services. It consists of only a hot (black) and neutral (white) wire with no ground wire. Both wires must run separately to fixtures as opposed to those used now which are contained within one plastic sheathing. There are many concerns with Knob and Tube: - most insurance companies wont insure - outlets , because there is no ground, will have two prongs, not three, and wont support ground fault circuit interrupters (GFCIs). - insulation was often rubber instead of plastic which degrades over time - it poses a fire hazard for many reasons which include overheating when it comes in contact with fiberglass insulation, critters can make short work of the insulation, can overheat about a ceiling fixture. - extremely costly to replace. Can range from $ 10,000-$15,000 for a 1500sq.ft.-3000sq.ft. home and take weeks to update
Posted on: Fri, 17 Oct 2014 11:14:55 +0000
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