One line diagrams that are used as part of an arc flash study must be up to date. NFPA 70E 120.1 Verification of an Electrically Safe Work Condition, requires checking up-to-date drawings, diagrams and tags when verifying an electrically safe work condition. In addition, when performing an arc flash study/risk assessment, an up-to-date one line drawing is the primary document that defines the system under study.
Jim Phillips discusses how, unless a study was performed, most companies do not have up-to-date electrical drawings. This is one of the many subjects discussed in Jim’s Electrical Safety and Arc Flash Training programs.