Talk:Bushing (electrical)
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[edit] Content that may need to me merged
A page was created with the title Anti-Short Bushing. As it is identical in concept to the topic of this page, I redirected here. The following is the content from the page. It needs clean up but it could be used as a basis for a history section. --Daniel J. Leivick (talk) 09:05, 12 December 2007 (UTC)
- In the late 1940's there were many fires that were attributed to electrical sources, particularly to the use of armored cable. Harry Freeman, the Manager of the Wire and Cable Division at CSA was given the task to investigate the problem. Bert Barraclough, Vice-President of Manufacturing, Triangle Conduit and Cable Canada was brought into the investigation and for some two years the two responded to every fire call in Toronto.
- The findings of the investigation were that the conductor insulation in the armored cable was being cut by the very sharp edges of the cut armor when terminations were being made.
- The two investigators found that the insertion of a hard, waxed fiber bushing between the armor and the insulated conductors would prevent damage to the insulation and the anti-short bushing was born. There were many attempts to make the bushing of other materials since the bushing that was put into use was quite expensive and no suitable alternative product was found until 1960. The idea of producing a molded plastic bushing that was stronger and could be designed for efficient insertion into the cable, came about.
- This was the origin of the anti-short plastic bushing that became the standard for the industry. There have been many refinements to the bushing and many attempts to copy the product but the plastic anti-short bushing has continued to be the industry standard to this day due to the continued quality assurance and technology improvements by the manufacturer working with the UL & CSA. There are now 19 different sizes available and they are manufactured in 90°C, 105°C, and 150°C material. They can be supplied with or without 3 indicator* tabs for easy identification by the electrical inspectors and to comply with CSA and UL requirements.
- External References
[1] [1] NEMA Engineering Department Bulletin No. 90, titled Use of Anti-Short Bushings for Terminating Type MC Cable [2] [2] Patent on the anti-short bushing [3] [3] The National Electric Manufacturers Association (NEMA)
(Link fixed). It's a bit hard to see the notability and importance of this material: it's extremely narrow in its scope. It's not the history of the electrical bushing itself, but of an investigation into a type fault of a particular design. I'm a transmission engineer myself, and I have never heard of this bushing, nor its type fault, nor of the individuals named. It's not mentioned in any of the three HV transmission textbooks I have to hand. — BillC talk 18:03, 12 December 2007 (UTC)
- Sure, I don't know anything about this topic. If the material is not needed then we can forget about it. Thanks for your help. --Daniel J. Leivick (talk) 18:59, 12 December 2007 (UTC)
