  鲜花( 30)   鸡蛋( 0)  
 | 
 
Earth Ground Testing 
$ h$ Z; w% Z1 c/ l 
% i; h1 B. U7 y/ i+ _8 x3 ?$ }4 rMost facilities have grounded electrical systems, so that in the event of a lightning strike or utility over voltage, current will find a safe path to earth. A ground electrode provides the contact between the electrical system and the earth. To ensure a reliable connection to earth, electrical codes, engineering standards, and local standards often specify a minimum impedance for the ground electrode. The International Electrical Testing Association specifies ground electrode testing every three years for a system in good condition with average up-time requirements.8 L+ q1 U# r5 _+ H8 b+ [ 
: n7 M5 x  f/ V8 q' B' h& a0 G 
Understand earth/ground principles and safety in more depth and then describes the principle testing methods: 3 and 4 pole Fall-of-Potential testing, selective testing, stakeless testing and 2 pole testing. |   
 
 
 
 |