INDUCTIVE LOADING FOR TELEPHONE FACILITIES 



739 



handle at the factory or during installation. The stub cable conductor sizes 

 have ranged from 13-gauge in the cases containing coils designed for com- 

 posite coarse-gauge toll cables to 24-gauge in the standard cases for the coils 

 used principally on 22 and 24-gauge non-quadded exchange cables. For 



Fig. 29 — Buried coaxial cable installation of voice-frequency loading on outer layer 

 quads. View of installation after completion of the splicing work, and prior to filling in 

 the excavation. The loading coils are potted in two tubular, thin steel, cases. Each of 

 black boxes near center covers a cable splice, and furnishes protection against mechani- 

 cal injury. At each splice, connections are made to the stub cable conductors of a single 

 loading coil case. Splicing difficulties prevent all of the connections from being concen- 

 trated at a single cable splice. 



several decades, 19-gauge stub cables were used for the toll cable loading 

 cases. The most recent case designs are using 22-gauge conductors. 



Dielectric Strength 



From the beginning of the use of cable loading, a fundamental design 

 requirement has been that the insulation of the loading coils and of the 



