Accident short circuit

Electrical accidents, including electrical arcing, short circuits, and overheated electrical equipment, are tlie leading cause of industrial fires. 

At present, measures such as replace the general electrical equipment and damaged cables can be used to solve not use explosion-proof electric equipment and short circuit fault of the electric cable thoroughly. But now there is no way to completely solve the problem of electrical equipment lost its explosion-proof ability, and the most common method used in coalmine is intensive inspection. The types of electrical equipment that lost its explosion-proof ability showed in accident cases have been collected, and got 5 common types of electrical equipments/devices, these 5 types are electrical switches, miner s lamp, exploder, electric coal drill, junction box, and specific distribution is shown in Figure 2. From the figure, we can know electrical switches, miner s lamp and junction box are the 3 main types of equipments/devices that prone to lose its explosion-proof ability, accounted for about 76.93% in total. 

Excessive current may fiow in a circuit as a resuit of an overioad or a short-circuit. An overload or overcurrent is defined as a current which exceeds the rated vaiue in an otherwise heaithy circuit. A short-circuit is an overcurrent resuiting from a fauit of negiigibie impedance between iive conductors having a difference in potentiai under normai operating conditions. Overioad currents usuaiiy occur in a circuit because it is abused by the consumer or because it has been badiy designed or modified by the instaiier. Short-circuits usuaiiy occur as a resuit of an accident which couid not have been predicted before the event. 

The electrical one-Une diagram (essential when performing lock out/tag out), short circuit and coordination studies, and other critical documents should be updated whenever system components change. Good documentation management supports accurate, efficient hazard analysis, and helps mitigate liability if an accident occurs. 

Metallic lithium has first been applied to primary batteries (non-rechargeable batteries), but it has not been applicable to secondary batteries (rechargeable batteries) up to now. During recharging of the lithium secondary battery, lithium metal tends to deposit as dendrites on the lithium surface. This lithium metal dendrites build up until they eventually cause an internal short circuit in the battery. Consequently, this often leads to a lire accident, as the battery continues to heat up. 

Battery safety is so important for mobile and vehicle apphcations. Especially for vehicles, on the road, accident likely becomes heavy, and the crash accident should not bring more danger by release of the energy stored in the cells. And various tests are usually conducted. In ZEBRA battery case, test results were reported. Crash of an operative battery against a pole with 50 km/h, overcharge test, overdischarge test, short circuit test, vibration test, external fire test, and submersion of the battery in water have been specified and performed [6]. The ZEBRA battery did pass all these tests owing to its four-barrier safety concept [7, 8] chemical aspects, cell case, thermal structure, and battery controller. 

The burn accidents invariably result from manual excavation when, for example, an operator using a pneumatic drill penetrates a concealed, buried cable with the tool. A short circuit will occur when the bit comes into contact with one or more of the live conductors and the metallic armouring and/or sheath of SNE cables or the CNE conductor where a PME distribution system is in use. The initial phase/earth or phase/neutral fault usually develops and involves the other phases, causing arcing which may emerge as a flame arc and blast from the hole made by the tool, injuring the operator. 

Lithium thermal batteries designed for use in U.S. Navy systems are subject to safety tests per Navy technical manual S9310-AQ-SAF, Battery, Navy Lithium Safety Program Responsibilities and Procedures. These tests are designed to assure that the battery design is safe not only in proper storage and use, but also when subjected to inadvertent misuse and conditions caused by accidents, such as backcharging, short circuits, and fires. 

The space industry, heavily dependent on cryogenics, has also been blessed with but few accidents. The disastrous fire of Apollo 1 resulted in the deaths of 3 astronauts. The cause of the Apollo 1 accident was attributed to materials incompatibility with pure oxygen gas at elevated pressure and ordinary temperatures within the command module. The explosion that took place in the Service Module of Apollo 13 as the astronauts were bound for the moon was caused by an electrical short circuit in an onboard supercritical cryogenic oxygen container. 

The Occupational Safety and Health Review Commission (OSHRC) initially addressed the employer-employee relationship shortly after the OSH Act was enacted in the case titled Gilles v. Cotting, Inc. In this case, two employees of the primary contractor were killed in an accident created by and resulting from the actions of a subcontractor. OSHA issued one citation to the primary contractor and one citation to the subcontractor. OSHA subsequently vacated the citation to the primary contractor, finding the citation was improper and would impose liability outside the employment relationship. Over the years, the OSHRC, as well as the various federal Circuit Courts of Appeal, has addressed this issue primarily in the construction area, with focus on creation of the hazard and control of the hazard. In recent decisions and with the inception of the multiemployer woiksite rule, the scope of the duty to safeguard employees at the worksite has been substantially expanded."... 

The investigations reported on by Clinton and Simmons (1987) also showed that the presence of dissolved oxygen in the solution results in an iodine partition coefficient lower by a factor of about 10, apparently due to the formation of volatile iodine species. This effect might be of interest in a steam generator tube rupture accident which happens shortly before a planned shutdown of the plant, after hydrogen had been removed from the coolant and/or H2O2 had been added to reduce the primary circuit contamination and radiation dose rates. In order to cover such conditions as well, in the US Guidelines a total iodine partition coefficient of 2 10 has been specified for tube rupture accidents. 

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