Environmental consideration that may warrant an SPD: long overhead power supply lines, rural, large buildings & commercial installations.
Zone 1: High Risk Area
Install ‘Coarse’ surge protection and cascading ‘Medium’ and ‘Fine’ surge protection.
SPB165R recommended
SPA212A recommended for lightning protection.
Zone 2: Medium Risk Area
Install ‘Medium’ surge protection and additional cascaded 'Fine' protection for critical sub circuits.
SPB140D recommended
Zone 3: Lower Risk Area
Install ‘Medium’ surge protection and consider ‘Fine’ surge protection for protecting final circuits.
SPB140D recommended.