Tag 13 : The term means a system or method of identifying circuits, systems or equipment for the purpose of alerting persons that the circuit, system or equipment is being worked on
Department of Energy AREA SAFT, DOE Handbook, Electrical Safety (Appendix B), Acronyms and Definitions, DOE-HDBK-1092-98, D.C. 20585, USA 1998. http://energy.gov/sites/prod/files/2013/07/f2/hdbk 1092.pdf, (Electr Sfty - Amer) {43}