Table 6. Insulation Resistance and Voltage Breakdown Tests (STU II-2) 



Insulation (15 mils thick) 



Insulation Resistance (Megohms) 



Voltage- 

 Breakdown^ 



Before Exposure JV 



After Exposure 



Exposed ( 



about 0.5 foot above the sediment=^ 





Straight wires 



Polyethylene 

 Polyvinyl chloride 

 Silicone rubber 

 GR-S (SBR) rubber 

 Neoprene 



20,100,000 



4,400,000 



6,200,000 



5,500,000 



36,000 



4,000,000 



600,000 



292,000 



320,000 



14,000 



Did not fail 

 Did not fail 

 Failed 

 Did not fail 

 Did not fail 



Exposec 



about 3 feet above the sediment^ 





Straight wires 



Polyethylene 

 Polyvinyl chloride 

 Silicone rubber 

 GR-S (SBR) rubber 

 Neoprene 



20,100,000 



4,400,000 



6,200,000 



5,500,000 



36,000 



885,000 

 240,000 

 208,000 

 225,000 

 12,400 



Did not fail 

 Did not fail 

 Did not fail 

 Did not fail 

 Did not fail 



Placed in piast 



ic tube about 4 feet above the sedimen 



tl/ 



Straight wires 



Polyethylene 

 Polyvinyl chloride 

 Silicone rubber 

 GR-S (SBR) rubber 

 Neoprene 



20,100,000 



4,400,000 



6,200,000 



5,500,000 



36,000 



480,000 

 192,000 

 197,000 

 158,000 

 8,700 



Did not fail 

 Did not fail 

 Did not fail 

 Did not fail 

 Did not fail 



Jy Average of 8 tests 

 "Ij Average of 2 tests 

 ^ Average of 3 tests 

 4/ Average of 3 tests; end membrane filters ruptured, and specimens were covered 



with mud. 

 5j Tested at 1,000 volts AC for 10 seconds. 



35 



