Maybe this will do.  NEC 374-6 For aluminum bars, the current carried continuously shall not exceed 700 amperes/in.² of cross section of the conductor.
  

busbar,

Thanks for the response. I am specifically seeking current ratings (ampacities) of rectangular aluminum bar of a 6101 alloy (electrical grade aluminum). The tables specify size (1/4" x "x", 1/2" x "x", etc.), orientation (horizontal or vertical mount), number of parallel bars, and alloy versus current ratings. Alcoa used to publish a handbook with tables such as I am seeking; however, I do not have a handbook and Alcoa can't seem to locate one.

P.S. I could not locate the code section quote you listed in the 2002 NEC. Did you make a typo or am I looking in the wrong section?

Try this, IT's the onlline version of the "Technical Data- A reference for the Electrical Power Industry".  It's worth downloading and sticking on a CD.


http://www.hubbellpowersystems.com/powertest/catalog_sections/Technical_Data.pdf

amptramp, it was a basic rule of thumb from the 1999 NEC.  Looks like you need more detail.  

BJC suggested a much more detailed reference.
  

I found this guide which shows how to calculate the current rating. I ran a couple size variations and the results were close to the tables I have. All the tables I have found stop at 1/2" thick bar.

http://217.153.88.147/Poradniki_guides/MV_DESIGN_GUIDE.pdf

Try:

www.copper.org/applications/busbar/ampacity/busbar.htm

Steve Smith, C.I.D.
Product Engineer
Staco Energy Products Co.
www.stacoenergy.com