A homebuilder is not entitled to the tax credit.

Does the 30% credit cover the cost of installation or labor?

The cost of labor to install solar equipment goes into the calculation of the total cost of your solar installation. Thus, solar installation is considered part of the 30% ITC. However, only the solar installation can be counted for part of your 30% ITC. For example, if you need something fixed on your roof in addition to the panel installation, that portion of the cost of the installation would not count.