Bulgarian in Bulgaria
Officially, the 24-hour clock is used in Bulgaria; however, when referring in conversation to social or business engagements, Bulgarians use the 12-hour clock. Train and airline schedules use the 24-hour clock.
In terms of protocol, one is expected to be on time for appointments. When invited to someone's home one may arrive five to ten minutes after the appointed time but not much later.
"What Time Is It?"Transcript document: