Carrying Capacity For A Copper Bar

It depends on temperature.........

Neither. A fine wire might work ok @ 5A/sq mm while a 20 X 100 mm busbar may take only 1A/sqmm. Skin effect, heat dissipation, many factors decide this. Please search CR4 for "busbar" or "current carrying capacity". You will get good information.

For God's sake ... do not size your bus bars based on such thumb rules. Bus bar sizing is an art. You have to do a lot of detailed calculations incorporating many rating/de-rating factors. And, not only the continuous current carrying capacity is a factor for sizing but also the voltage drop, the thermal withstand capacity of the bus bars during a short circuit as well as the electro-dynamic withstand capacity of the bus bar during a short ciruit are equally important while sizing bus bars.

COPPER CURRENT CAPACITY IS 1.2A PER SQMM

ALUMINIUM CURRENT CAPACITY IS 0.8A PER SQMM

For Gods sake! Doesn't anybody read all comments b4 posting? This is a recipe fr disaster ! PLEASE IGNORE ALL VALUES OF xx amps/sq mm. THERE IS NO SUCH THING !