Bus Bar Ampacities

[blues]

Does anyone know to calculate the ampacitiy for a 1/4" x 4" aluminum busbar?

Dan Craven

 

[ryan_618]

Well, the code dose have this:

366.23 Ampacity of Conductors.
(A) Sheet Metal Auxiliary Gutters. Where the number of current-carrying conductors contained in the sheet metal auxiliary gutter is 30 or less, the correction factors specified in 310.15(B)(2)(a) shall not apply. The current carried continuously in bare copper bars in sheet metal auxiliary gutters shall not exceed 1.55 amperes/mm2 (1000 amperes/in.2) of cross section of the conductor. For aluminum bars, the current carried continuously shall not exceed 1.09 amperes/mm2 (700 amperes/in.2) of cross section of the conductor.

 

[LarryFine]

Sounds like 700a to me.

 

[benaround]

It is equal to 1220 cir. mils.

1/4 x 4 cu. equals 1700+ amps.

per/ Copper.org

 

[LarryFine]

. . . a 1/4" x 4" aluminum busbar?

Well, the code dose have this:

. . . 700 amperes/in.2 . . .

1/4 x 4 + 1. Why wouldn't that be 700a?

 

[joemcg]

Aluminum busses are rated at 700 amps per square inch; Copper is 1000 amps.

 

[ryan_618]

Aluminum busses are rated at 700 amps per square inch; Copper is 1000 amps.

Thanks Joe!

 

[kc8dxx]

Here is a link to an absurd amount of information on copper busbars:

http://www.copper.org/applications/busbar/homepage.html

 

[benaround]

I don't see where 366.23 has any information on the ratings of busbars, To

me,it says that if using busbars in sheet metal auxiliary gutter that certian

ampacity limitation must be followed. If these are limitations then the busbar

must have a larger ampacity.