Flammable Gas Explosion in Large Oil Circuit Breaker

Although it has long been realized that flammable gases were produced by the decomposition of solid insulation and insulating oil due to faults in electric equipment, this generally has not been considered an explosion hazard in the operation or maintenance of the equipment. On August 15, 1962, an explosion of flammable gases was experienced in a 161-kv oil circuit breaker tank at the Oak Ridge gaseous diffusion plant. The breaker had been drained of oil and opened for inspection to determine the cause of high contact resistance detected during routine testing of the breaker. This searing blast was the direct cause of death of one employee and resulted in minor injury to five others. Because of the unexpected nature of this hazard and its wide existence in the electrical industry, this paper proposes to acquaint the industry with the incident and to promote further investigation into the handling of insulating oil.