Knob-and-tube wiring was common in North America from about 1880 to the 1930s. It consisted of single-insulated copper conductors run within wall or ceiling cavities. New knob and tube installations are permitted in the U.S. only in a few very specific situations.
About Knob-and-tube wiring in brief
Knob-and-tube wiring was common in North America from about 1880 to the 1930s. It consisted of single-insulated copper conductors run within wall or ceiling cavities. Wire splices in such installations were twisted together for good mechanical strength, then soldered and wrapped with rubber insulating tape and friction tape. Knob and tube wiring was eventually displaced from interior wiring systems because of the high cost of installation compared with use of power cables. New knob and tube installations are permitted in the U.S. only in a few very specific situations listed in the National Electrical Code, such as certain industrial and agricultural environments. Under the US electrical code, even permissible new installations of K&T wiring have now been banned, even for existing wiring systems. However many older electricians must be aware of this older system, which is still present in many older K&O installations. By contrast, modern electrical codes now require that all residential wiring connections be made inside protective enclosures, and that all connections must remain accessible for inspection, troubleshooting, and repair, if necessary.
For more information on wiring in the UK, visit the Electrical Wiring Association. For the Electrical Engineering Society, visit their website, the Electrical Engineer’s Society, and for the American Institute of Electrical and Electronics Engineers, see the Electrical Engineers’ website, The Electrical Engineering Association, and the American Institution of Engineering and Technology, both of which are based in Washington, D.C. The Electrical Engineers, of which I am a member, is a trade body for the electrical industry, and is based in New York, California, Oregon, and Washington, DC. For. more information, visit www.electricalequipment.org, or the Electrical Equipment Association, of whom I am the president and chief executive officer, based in San Francisco, California. For a. more detailed building wiring diagram, see http://www.electricequipment association.org/building-wiring-diagrams/knob-&-tube.
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This page is based on the article Knob-and-tube wiring published in Wikipedia (as of Dec. 09, 2020) and was automatically summarized using artificial intelligence.
