Should I use type II or type I_II SPD DC boxes?

Surge protection devices are intended to protect electrical devices from voltage spikes. The

“Type” refers to the level of protection supplied by the SPD unit.

Type I_II provides a higher level of protection against direct lightening strikes on the other hand Type II provides protection against generic over voltages in a system. As such, installers must conduct a lightening risk assessment for the installation site before determining which SPD to use.

As a general rule areas in the highveld (e.g. South African inland areas) have more frequent lightening strikes compared to areas in the lowveld (e.g. South African coastal areas). Therefore, Type I_II SPDs are recommended for highveld areas and Type II SPDs are recommended for lowveld areas.

For further information please refer to this document

https://portal.segensolar.co.za/reseller/docs/Importance%20Of%20Lightning%20Protection%20For%20Residential%20And%20Commercial%20Solar%20PV%20Systems.pdf