Quote from: tuanbusku on September 13, 2018, 06:56:21 AM

In united states, anyone knows who should I contact to add another 200A service to my garage? Power supply company or electrician? I currently have one 200A service in basement which is fully occupied

Start with the power company.

They will know what your service options are and weather you can upgrade your existing service or add a second meter. Mine will not allow a second meter at the house, but they will allow 1 extra meter to a shed/outbuilding. They will also tell you what permits if any would be needed from the county/city. I would need a pre-install permit from the county and a post-install inspection also by the county. Once you know what options are available from the power company and what regulatory hoops you need to jump through for the local jurisdiction, then you can contact an electrician to do the work.