measuring current capacity on bus bar

http://www.copper.org/applications/busbar/ampacity/bus_table1.html

Google copper bus bar ampacity.

To find bus bar ampacity (allowable number of A e.g. 200A) you need to know:

1. Localisation of your installation i.e. your Country - and its Codes e.g. in USA - NEC 2008.
2. Temperature - max ambient e.g. 50°C or 122°F
3. Material : Cu (copper), Al (aluminium) etc.
4. Your max current in A, the one that your designed bus must handle.
5. You have access to Internet - do search as wareagle did for Cu finding table for bar's dimensions in inches. You may need to find bar measured in mm.
6. Number of bars, e.g. in three-phase systems you need mostly three bars. Their arrangements and distances between the phases are also function of expected short circuits current which also has to be calculated so construction supporting bars will not fail/be crashed by dynamic forces.

This is a practical way in selecting material and size of the bar(s)

hi

you refere IEC 60947 pt. 1, UL 508, IS 13947 pt.1 and IEC 60439 pt.1 & IS 8623 pt. 1 for current capacity of bus bar,

for simple cacluation you must have idea of current to be handled, current density of copper or aluminumu, maximum allowable temperature in service condition, derating factor,

i.e. for 1000 A if density of copper is 1.5 A/mm2 then it required to have 1000/1.5 = 650 mm2 area that has to be further maultiplied with derating factor which is always more thatn unity (1).

regards

divyesh patel