This standard covers the requirements and tests for portable direct reading, three and four terminal earth resistance meters ( hand-operated ), enclosing in the same case, a generator having a rated frequency within 60 to 90 Hz and voltage in the range of 30 to 250 V for measuring earth resistance and earth resistivity, with four terminal instruments.
NOTE — The earth resistance meter is also suit-able for terrain and mountainous areas for measuring earth resistance and even for places where powerful stray earth currents exist.