Busbar System

Usually nothing. If system is properly designed and constructed.

Here is a good paper if you on a quest for knowledge: ect162.pdf

Although a short circuit test, if successful, will leave a working system (after all that is the aim) I would not want to put such a system into real service after such a test. By definition, a short circuit test takes a system to the very limit, beyond normal service levels. In fact the perfect test should be within 1% of failure (if it is to be economic). Any fool can ensure a test is passed, it is more difficult to make it just pass.

In the case of busbars, the supports will have been stressed mechanically and the bars will have been very hot - possibly passed the annealing temperature. Busbars and supports may have moved (which is allowed within limits).

I would describe the equivalent test as running your car into a brick wall to test the bumpers and the airbags. You should be able to walk away, or even drive away, but the car may have some damage not immediately apparent.

If not designed properly, short circuit current could melt down the busbars (thermal effect) and deform them (Dynamic Effect).