scope:

This document covers the electrical coordination between primary and secondary surge protection devices or components for a single conductor line that may have an earth ground connection reference. Additional information covering coordination, such as dual conductors connected that may have an earth ground connection reference, is included in the annexes. Proper coordination is essential to ensure that both primary and secondary protectors function in a manner that provides the protected equipment with the most effective protection from ac power fault conditions or lightning induced or industrial equipment induced surges. This document does not address protection of the ac power service.