temperature rise in bus bar 1

[hogdawg]

I am confused as to why bus bar ampacity tables show a higher ampacity of bus sizes with a higher degree of temperaturs, i.e. 50 deg. C apposed to say 75 deg. C.
anybody know?

Thanks

 

[wareagle]

Check this location for information.

http://www.copper.org/applications/busbar/ampacity/busT4.htm

 

[mohpower]

it is the temperature rise. a 75degC rise busbar is carrying more current than a 50degC rise one. if a given size of busbar is made (by cooling) to support a temperature of 150degC and carry a current of 1000 amps say, the same busbar will carry less curent if it made to support a yemperature 100degC

Is it right?

thanks

 

[ravishankarazad]

The current carrying capacity of any bus is determined by the amount of current the conductor can accommodate for a given temperature rise. Current carrying capacity can be considered a function of temperature rise.
The greater the ability to dissipate heat the greater the current carrying capacity. So higher the temperature allowed in the conductor,higher current it can take.

Regards,
Ravishankar Azad