LEAD-COVERED PAPER-INSULATED TELEPHONE CABLE 461 



Testing Lead Covered Cable 

 After the cable is stranded each conductor is tested from end to end 

 for continuity and against every other conductor for crosses. Defects 

 are repaired and after the cable core has been dried the lead sheath is 

 applied. After the application of the sheath the cable is allowed to 

 stand until it cools to room temperature. Fig. 29 shows the cooling 

 floor and test mezzanine in the Point Breeze cable plant. The reels of 

 cable issue from the lead presses at the right; are cooled in the central 

 area and tested beneath the mezzanine at the left. 



Fig. 29 — ^CooIing floor and test mezzanine. 



When the cables are cooled the conductors are given a final test for 

 opens and crosses which may have developed due to strains imposed 

 during the sheathing process. Most toll cables have a number of spare 

 wires and if fewer than the allowable number of above defects are found 

 the cable is tested for dielectric strength, insulation resistance, mutual 

 capacitance, capacitance unbalance and defects in the sheath. Die- 

 lectric strength tests are made between each conductor and every other 

 adjacent conductor to which failure may occur and between all 

 conductors and the lead sheath. The potential used for these tests 

 ranges between 350 volts, A.C., the lowest value used for certain con- 

 ductor to conductor tests and as high as 5,000 volts, A.C. for some 

 conductor to sheath tests. In making the conductor to conductor 

 tests a large number of circuits are involved so that interesting prob- 



