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Rationale and Application of 50 V Threshold in NFPA 70E

Question asked by nicholas.harknett on Dec 6, 2019
Latest reply on Dec 6, 2019 by rcramereleceng

Good Day,

  In the process of setting appropriate safe work conditions for use on various pieces of electrical equipment, the team at my organization has uncovered some questions on appropriately applying the 50 V threshold for de-energized work.  


  Is anyone aware and willing to share the rationale behind the selection of 50 V as the threshold with no definition around AC vs. DC?  When reviewing the European low voltage directive, the threshold is at 75 VDC vs. 50 VAC and definitions of Class A vs. Class B voltages indicate a threshold of 60 VDC to differentiate voltage classes for hazard identification.


  I appreciate your expertise and experience as we try to navigate the most appropriate way to implement NFPA 70E best practices without missing the intent or causing undue concern.