NEMA SPD 1.1 :2019

This specification guide is Part 1 of a series of such guides that is intended to provide guidance on the evaluation, specification and/or use of surge protective devices (SPDs) deployed in low voltage power distribution system applications. This specification guide describes a uniform specification methodology for SPDs, containing at least one non-linear component, that are connected to or within a 50/60 Hz power distribution equipment that is rated up to 1000 Vac. Such SPDs are specifically intended to mitigate the transient overvoltage effects to end-use equipment.
This guide is not intended to introduce new standards, derive tests, create an evaluation methodology, or define extensive vocabulary. It is intended to guide those who are evaluating and/or comparing the essential parameters of SPDs. The parameters being compared are measurable using available commercial test equipment and/or established standards and measurements as referenced in Section 1.2.