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Kevin
Kevin, Licensed Electrician
Category: Electrical
Satisfied Customers: 2944
Experience:  29 years as a Licensed Electrical Contractor in Illinois, 5 year college Electrical Instructor, Former Electrical Inspector, Diploma in Digital Electronics, Former Illinois Licensed Home Inspector
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With aluminum flat bar busses, conical washer on one side and

Customer Question

with aluminum flat bar busses, conical washer on one side and flat thick washer on the other side, why?
with copper flat bar bus, both sides, flat washer and safety washer on the but side, why?
tku
eduardo
Submitted: 1 year ago.
Category: Electrical
Expert:  Kevin replied 1 year ago.
Hello.....my name is ***** ***** I will be happy to assist you with your electrical question. My goal is to exceed your expectations on Just Answer!
1) The conical washers that you are referring to are commonly used on Aluminum bus bars to provide a "spring like" or more of an even tension at the connection point. In the fastening and electrical industry, these washers are known as" Belleville Washers".
An aluminum bus bar has a different "coefficient of thermal expansion" as compared to a copper bus bar.
2) Due to the difference in the thermal expansion properties of aluminum versus a copper bus bar, Belleville washers are commonly used on aluminum terminations.
3) Belleville washers are also commonly used on electrical connections where dissimilar metals are joined together.
4) Shown in the links below are two good articles explaining the use of Belleville washers in greater detail.
http://ecmweb.com/content/how-use-belleville-washers-correctly
http://www.solonmfg.com/springs/pdfs/ElecConnWhitePaper.pdf
5) As always, it is recommended to follow the manufacturer installation instructions as to the types of washers to be used. By not using the manufacturer supplied and/or recommended washer types, this can void the "UL" or "ETL" listing of the product and can result in a code violation.
Hope this helps………If you have any additional questions, let me know and I’ll be glad to answer them for you.
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The next time you have an electrical question, you can also request for me at: http://www.justanswer.com/home-improvement/expert-your-electrician ……….Thanks…………..Kevin!
Expert:  Kevin replied 1 year ago.
If you have any additional questions, let me know and I’ll be glad to answer them for you.
Otherwise, don’t forget to rate me before you log Off.
Expert:  Kevin replied 1 year ago.
1) Did my reply answer your questions?
If you have any additional questions, let me know and I’ll be glad to answer them for you.
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