I installed an air compressor in the garage, that needed 220v. I decided to use a 14-50 outlet for the compressor as i could use a 50amp- to 30 amp cable to connect my travel trailer. That way i'm not running the air conditioning through a small 12 or 14 gauge 110v cord. I also back feed the panel with my generator during power outages , through the same outlet. It is wired with number 6 wire so i can also run my tombstone welder if needed.