This Software package is designed to give indicative
current ratings and power dissipated for Aluminium and Copper BusBars
as used in switchboards and electrical distribution systems. The user
is able to specify the thickness and the width of the BusBar for thicknesses
BusBar ratings are based on the expected surface temperature
rise of the busbar. This is a function of the thermal resistance of
the busbar and the power it dissipates. The thermal resistance of the
busbar is a function of the surface area of the busbar, the orientation
of the busbar, the material from which it is made, and the movement
of air around it. The power dissipated by the bus bar is dependant on
the square of the current passing through it, its length, and the material
from which it is made.
Optimal ratings are achieved when the bar runs horizontally
with the face of the bar in the vertical plane. i.e. the bar is on its
edge. There must be free air circulation around all of the bar in order
to afford the maximum cooling to its surface. Restricted airflow around
the bar will increase the surface temperature of the bar. If the bar
is installed on its side, (largest area to the top) it will run at an
elevated temperature and may need considerable derating. The actual
derating required depends on the shape of the bar. Busbars with a high
ratio between the width and the thickness, are more sensitive to their
orientation than busbars that have an almost square cross section.
Vertical busbars will run much hotter at the top of the
bar than at the bottom, and should be derated in order to reduce the
maximum temperature within allowable limits.
Maximum BusBar ratings are not the temperature at which
the busbar is expected to fail, rather it is the maximum temperature
at which it is considered safe to operate the busbar due to other factors
such as the temperature rating of insulation materials which may be
in contact with, or close to, the busbar. Busbars which are sleeved
in an insulation material such as a heatshrink material, may need to
be derated because of the potential ageing and premature failure of
the insulation material.
The software provides calculation in both metric and imperial
The power dissipation in busbars can be calculated
for specific currents.
Purchase Price for BusBar Calculations is $NZ35 or $US22.
Click here to
download Electrical Calculations
(including busbar calculations)