In total, there are three different types of surge protection device (SPD): Type 1 is specifically recommended for service and industrial buildings, type 2 is the main protection system for all low-voltage electrical installations and the type 3 surge protection device has a low discharge capacity and must therefore be used as a mandatory supplement to type 2. Weidmüller DC combiner boxes commonly has Type 2 SPD, that is the standard in the PV industry. However, it is possible to change this SPD for another one that adapts more to a particular circunstance. To select the correct surge protection device, we recommend that you take the previous information into account and take a look at the table in this fact sheet, which lists all the surge protection devices (DC and AC) that Weidmüller has in its catalogue.