On December 11, 2019 @ 17:21 hrs, Units were dispatched for burning smell in a commercial building. Units AOS to find a slight haze and burning smell. Checked store - believe cause to be the HVAC unit. Power secured to HVAC unit and breaker #26 - which connected equipment had been tripping breaker. T28 checked roof and next door vacant store front - No smoke/fire. Tenant advised to leave breakers off and contact repairman in the morning. Command terminated and units cleared the scene at 18:22 hrs.