Second Technique 



Although the technique just described works quite well, the fabri- 

 cation of the Tygon/butt connector/ Tygon sequence is inconvenient, and, 

 if not done with care, the splice can leak. To eliminate this, a butt 

 connector, which consists of a butt-crimp connector inserted halfway 

 into a 6-inch (15-cm) nylon tube, was designed and fabricated (Figure 2A) 

 The procedure for filling the butt connector assembly with RTV and the 

 technique of performing the underwater splice itself are identical to 

 the technique described above. The finished splice is shown in Figure 2B. 

 Using this extended butt connector assembly eliminates any inconvenience 

 and allows the entire splice preparation to be done at sea. If necessary, 

 these butt connectors can be filled with RTV just prior to use if the 

 RTV is allowed to set for an hour to start curing. 



TESTING 

 Pressure Vessel 



During the testing, 24 splices were prepared using the technique 

 employing Tygon tubing: six with AWG 16 PVC-insulated wire, six 

 with AWG 18 PVC-insulated wire, and the remaining 12 with Teflon- 

 insulated wires ranging from AWG 22 to AWG 12. 



These splices were checked for electrical leakage in the CEL Pressure 

 Vessel while cycling the pressure from to 500 psig (34 atm) at two 

 different temperatures: one near 18°C and the other near 3°C. All leakage 

 measurements were made with a 1 -kV DC and 600 volts AC, 60-Hertz, high- 

 voltage insulation tester. The DC measurements were estimated to the 

 nearest 0.25 uA, and the AC to the nearest 0.1 uA. When making leakage 

 resistance measurements dealing with thousands of megohms, the stray 

 leakage of the test vessel wiring becomes an important factor. To take 

 this into account, the wire to be spliced was connected to the pressure 

 vessel plug, and the leakage resistance of the measuring system was taken. 

 Then, the wires and the penetrator plug were removed, and the wire was 

 cut. Splices were then made underwater and again measured for leakage 

 current. The test data indicate that the additional leakage current 

 measured due to the underwater splice is very small, and that the leakage 

 of a normal splice is on the order of thousands of megohms. 



All the splices showed a leakage current of less than 1.5 uA at 

 both voltages. The splices were cycled and tested for a period of 2 

 weeks. They were then tested in the pressure vessel at 500 psig (34 atm) 

 at 3°C to determine long-term performance. After 4 months with no fail- 

 ures the splices were removed from the pressure vessel. 



At-Sea Operations 



There have been numerous at -sea repairs of electrical cable accom- 

 plished by CEL divers. The faulted wires that required repair were single- 

 conductor AWG 18. The insulation was a dual -wall radiation, cross-linked 



