Forced air cooled bus SC Withstand Rating

[Designer69]

Gents,

if a non-cooled bus bar with a certain SC withstand rating is retrofitted with a force air cooled enclosure, effectively increasing the current carrying rating of the bus, will this also increase the SC withstand rating of this same bus or is it unchanged?

thanks

 

[jim dungar]

The SC rating is effectively based on magnetic forces, not current carrying capacity.

 

[rcwilson]

Current carrying rating is based on thermal considerations that are affected by cooling.

Short circuit ratings are based on structural and physical characteristics that are not affected by temperature or cooling. Bus bars will be pulled together or pushed apart violently during high short circuit currents.