The actual work of installing photovoltaic solar electric systems is essentially a construction job. The work involves assembling racking systems, installing the equipment on rooftops or other infrastructure, assembling electrical wiring, verifying the wiring works, and connecting it to the grid.
Once you get past the unique bits – assembling racking systems, and wiring solar panels – the tools of the trade are the same as are used in other construction or electrical work.
Solar installers must know certain portions of the electrical code. They interact with building inspectors who approve or fail the installation.