Figure 34. Glass microscope slides and electrical wire Insulations. 



Electrical Cable Insulation for Single Conductors and Muiticonductors . The 

 insulations of the 10-inch-long electrical cables (Figure 35) were examined under 

 a microscope for signs of any blodeterioration and for any physical effects of the 

 deep sea environment. 



Blodeterioration due to borer activity was more pronounced (especially in the 

 area of a wood bait piece) on a set of electrical cable insulations which were 

 exposed about 0.5 feet above the sediment layer than on an Identical set of insula- 

 tions which were exposed about 3 to 4 feet above the sediment. The insulating 

 materials which were damaged by the borers under a wood bait piece were nylon, 

 silicone rubber, vinyl resin rubber, and fluorlnated ethylene propylene (FEP). The 

 borers had penetrated the FEP insulation, exposing the wire conductor to the seawater 

 environment. 



The insulating materials which were neither affected by borer activity nor by 

 the deep sea environment were bakelite, natural rubber, neoprene rubber, and 

 polyethylene. 



In addition to damage caused by the borers under the wood bait piece, the 

 surface of the silicone rubber Insulations were damaged by the nibbling and biting 

 action of some marine organisms. 



42 



