CABLE TESTING 



681 



The faulty wire is looped with Z and the resistance, R lt of 

 the loop measured by a bridge. 



Ri = (x + y) + Z. 



Loop the faulty wire with W and measure the resistance, # 2 , 

 of this loop. 



#2 = (x + y) + W. 



-w- 



tr 



FIG. 424. Pertaining to determination of resistance of faulty conductor 



Lastly, loop W and Z and measure the resistance, R 3 , of the 

 loop. 



Then 



(a; + y) 



. = W + Z. 

 RI -\- Rz 



/n v 

 (9) 



Another procedure is to loop the faulty wire with Z and 

 measure the loop resistance, R\. 



Ri = (x + y) + Z. 



W and Z are then looped and grounded at B, and Z measured 

 by one of the previous methods; then 



(x + y) = Ri - Z (10) 



w- 



** 

 FIG. 425. Pertaining to determination of resistance of faulty conductor. 



If there are one perfect and two faulty wires of the same length 

 and resistance connecting the stations, as indicated in Fig. 425 

 the total resistance of either of the faulty wires may be obtained 

 thus: 



