... in electric power, telecommunications, meteorology, oil field, construction, lightning protection, industrial electrical equipment and other earth ground resistance measurement. ... -20°C~60°C, below 70%rh 30.Overload Protection :Measuring earth ground resistance: between each interfaces of E- ... 4-3,Wireless frequency electromagnetic field≤1V/m 34.Protection Type: IEC61010-1,IEC1010-2-31,IEC61557-1,5 ...