Analysis of the Difference and Relation of Safety Assessment Standard of Two Grounding Systems
Ding Dai-yong · Mechanical & Electrical Engineering Technology · 2007
Safety assessment of grounding systems is a testing that the actual maximum touch and step voltages are computed and compared to the maximum allowable(safe) touch and step voltages.IEEE Std 80-1986 and IEC-479-1 are defined the standard of safety assessment of grounding systems.Both standards define safety criteria in terms of allowable body current.The allowable body current is then translated into the allowable touch and step voltages.The paper compares actual touch and step voltages with the standard values which are computed by IEEE Std 80-1986 and IEC-479-1.By means of an example,the conclusion is derived that the IEC-479-1 is more conservative than the IEEE Std 80-1986.We will get reasonable result if we combine IEEE Std 80-1986 with IEC-479-1.