On August 4, 2016 the 2017 edition of the National Electrical Code® (NEC) was released. This edition of the code introduced a requirement for Surge Protective Devices (SPDs) in Industrial Machinery with safety interlock circuits. The requirement is in Article 670.6 and reads: “Industrial machinery with safety interlock circuits shall have surge protection installed.” This application note will examine the code requirements and definitions. It is intended to help engineers at machinery builders and the associated control panel builders understand the requirements and make recommendations to them in implementation.
