Title :
NEC requirements of isolated safety ground for medium voltage mobile or portable equipment in industrial environment
Author :
Robertson, William F. ; Das, J.C.
Author_Institution :
Simons Eng Inc., Decatur, GA, USA
Abstract :
The National Electrical Code specifies that an isolated safety ground, separated by at least 20 feet from the system ground, should be created for grounding of mobile or portable medium voltage equipment. This paper demonstrates that isolation of the system ground and construction of a separate safety ground may not be practical in industrial, nonmining environments. Coupling between these grounds occurs through soil resistivity even if it is possible to eliminate all metallic bonds between the two grounding systems. Worker safety is enhanced if all grounds are solidly bonded together. This is particularly true if an equipotential ground plane can be established throughout the work area in which medium voltage portable or mobile equipment operate.
Keywords :
earthing; industrial power systems; power apparatus; power system protection; safety; standards; MV power apparatus; NEC requirements; National Electrical Code; equipotential ground plane; industrial environment; isolated safety ground; isolation; personnel safety; power systems; soil resistivity; worker safety; Conductors; Electrical equipment industry; Electrodes; Grounding; Medium voltage; National electric code; Safety devices; Strontium; Substations; Transformers;
Conference_Titel :
Pulp and Paper, 1999. Industry Technical Conference Record of 1999 Annual
Conference_Location :
Seattle, WA, USA
Print_ISBN :
0-7803-5526-1
DOI :
10.1109/PAPCON.1999.779368
