**ROUND ROD**

Diameter ^{2} in mm x 0.00701 = mass in kg/meter.

**SQUARE BAR**

Width across flat ^{2} in mm x 0.00889 = mass in kg/meter.

**RECTANGULAR BAR**

Width x Thickness in mm x 0.00889 = mass in kg/meter.

**ROUND TUBE**

(Diameter - Wall Thickness) x Wall Thickness x 0.028 = mass in kg/meter.

I = Current in Amperes

A = Cross Sectional Area in mm^{2}

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 A^{0.5}p^{0.39}

**For Hollow Round Bars**

I = 8.63 x A^{0.5}p^{0.36}

**For Solid Round Bars**

I = 13.6 x A^{0.68}

**Hollow Round Bars (Bustube)**

I = 8.63 x A^{0.5} x p^{0.36}