Several changes to the standard were implemented from 2nd to 3rd edition. Some of the terminology was changed to use three letter acronyms to align better with how terminology is used in many international standards. For example, TVSS which refers to “Transient Voltage Surge Suppressor” in 2nd editions is now termed as SPD or “Surge Protection Device”. Another significant change was the addition of type designations. Type 1, 2, and 3 are used for SPD devices based on installation location within the electrical system. Type 4 and 5 are reserved for suppression components such as MOV devices or components assemblies such as the Littelfuse TMOV® Thermally Protected MOV. This will be discussed in more detail later in this presentation.