Is Absence of Voltage “Live-Dead-Live” Testing According to NFPA 70E Adequate?

As the second to last step for an electrically safe work condition (ESWC) to exist, testing for the absence of voltage, commonly called “Live-Dead-Live” testing, is one of the most critical tools to ensure the safety of workers from electric shock and arc flash hazards. It has been required by NFPA 70E® - Standard for Electrical Safety in the Workplace [1] since the 2004 edition, with slight changes between revisions. The 2021 version houses this very important practice in article 120.5(7) which states in part “Use an adequately rated portable test instrument to test each phase conductor or circuit part to test for the absence of voltage. Test each phase conductor or circuit part both phase-to-phase and phase-to-ground.” However, the term “phase-to-phase” is synonymous with only alternate current (ac) systems and “phase-to-ground” with only intentionally grounded ac systems. Contrary to this, ungrounded distribution systems and now with the proliferation of direct current (dc) circuits, especially with the electric vehicle charging stations, solar power plants and dc distribution systems, the terms “phase-to-phase” and “phase-to-ground” doesn't appear to be adequate or applicable in today's ever-changing world of electrical technology. Secondly is the frequency to reperform absence of voltage testing once the initial has been performed per 120.4(6) seems inadequate as currently stipulated. This paper will provide a basis that article 120 should be updated for greater technical accuracy and clarity which will provide greater safety margin for workers who are exposed to additional electrical hazards found in today's modern equipment.