A321 Captain reported the fire extinguishing system CB popped out for the second time. A divert was initiated.

Narrative

One hour into flight from ZZZ to ZZZ1 one circuit breaker tripped; south of ZZZ2.I became pilot monitoring.FO becoming pilot flying with ATC radio duties.I used crew phone app calling dispatch over Bluetooth and patched in Maintenance Control; and we discussed that extinguishing unit and system itself is inop; and one-bottle configuration does not have itself an automatic fire extinguishing capability. FO did excellent; and was kept in discussion loop.With entire cargo extinguishing system rendered inop; and 3.5 hours to go to ZZZ1; safest decision to divert to ZZZ3 was made; with everyone in total agreement.This exact circuit breaker had popped before; Maintenance Control stated.ZZZ3 was 370 miles away; perfect weather; and enough miles to go (for more fuel burn); to get landing weight to an appropriate level; so we do not have to do overweight landing.Dispatcher provided via Acars; ZZZ3 weather; related Notams and flight destination amendment.However; we learned from ZZZ3 approach control later; that ARFF vehicles will be available upon landing.ATC asked (so we advised) XXX souls on board and 190 minutes approximately fuel on board.I called flight attendants to advise them of issue and to expect normal landing in about half an hour; and I made a reassuring PA.ATC cleared us to ZZZ3 via ZZZZZ;and we entered hold at 14;000 and 230 kts; over ZZZZZ1; north as published; to bring landing weight down.FO calculated fuel and weight numbers correctly. I made another reassuring PA.Exited hold; once assured no overweight landing.ZZZ3 Tower cleared us to land on runway XX; the longest.Very nice landing by the FO.Tower was told that we do not need any assistance.We taxied to gate.Entry made and maintenance met aircraft. We swapped into a different aircraft;and proceeded with same passengers and same flight attendants to ZZZ1.FO did excellent; and certainly helped a lot.Flight attendants; dispatcher; Maintenance Control; were great; as well.Successful; smooth outcome.Cause: Increase maintenance personnel numbers; to be able to increase maintenance aircraft supervision; for example; increased troubleshooting of root cause; when same circuit breaker first popped previously.