Diameter 2 in mm x 0.00701 = mass in kg/meter.
Width across flat 2 in mm x 0.00889 = mass in kg/meter.
Width x Thickness in mm x 0.00889 = mass in kg/meter.
(Diameter - Wall Thickness) x Wall Thickness x 0.028 = mass in kg/meter.
I = Current in Amperes
A = Cross Sectional Area in mm2
p = perimeter of conductor in mm
Assume that the temperature rise of the conductor is 50°C above the ambient temperature of 40°C, and the resistivity of Copper at 20°C is 1.724 micro Ohm cm, then the current ratings are:
For Flat Bars
I = 7.73 x A0.5p0.39
For Hollow Round Bars
I = 8.63 x A0.5p0.36
For Solid Round Bars
I = 13.6 x A0.68
Hollow Round Bars (Bustube)
I = 8.63 x A0.5 x p0.36