ABSTRACT
Photovoltaic (PV) is growing fast, and the PV material in the National Electrical Code (NEC) is changing faster than anything the NEC has seen since the days of Thomas Edison and Nikola Tesla hashing it out over dc vs. ac. It appeared that Tesla was right when 2-phase ac power was installed at Niagara Falls: ac was the way of the future, but the future is always unpredictable, and with PV and energy storage, dc is making a comeback. When the 2023 NEC comes out, this material will not be obsolete; in fact, more than half the PV in the United States is installed in places that adopt the NEC three years after a Code is released. For instance, the state with half of the solar in the US is California, and in California, the 2017 NEC was adopted in 2020 and used until the 2020 NEC is adopted in 2023.
