95% of the A320 CBs are in the cockpit, and accessible to flight crew on the overhead (49VU) and behind the F/O (121VU &122VU)....
Resetting however should only be done according to the "Computer reset Procedures" published in the QUICK REFERENCE HANDBOOK.....some resets are allowed in flight, most are only allowed on ground....
Moreover, some CBs on A320 are monitored by the FLIGHT WARNING COMPUTER and tripping of one of them can generate a caution message that points to the tripped CB.