Underwater electric fields can be generated from an undetected ground fault in the pier power system, a powered cathodic protection system, or a fault in the lighting and inspection devices carried by the diver. Divers performing underwater inspection of piers and offshore structures can swim near hazardous electric fields. The shock hazards to the diver who swims into an elec-_ trie field are the same as described earlier in this text, but no contact with any part of the electrical equipment is necessary. If a diver swims into an electric field, his/her body will be exposed to a potential (voltage) equal to the difference in field intensities of the point closest to and furthest from the fault or source. Tests conducted on human volunteers have shown that electric field strengths of approximately 0.5 V/ft can result in currents as high as 5 ma through the chest. Higher field strengths could result in loss of muscular control or, in the worst case, ventricular fibrillation.
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