IEEE Std 463:2019 pdf free download – IEEE Standard for ElectricalSafety Practices in ElectrolyticCell Line Working Zones
cell voltage: The de voltage between the positive and negative terminals of one electrolytic cell.
electrical hazard: A condition where contact or equipment failure can result in electrical shock, arc flash burn,thermal burn, or blast.
electrolytic cell: A receptacle or vessel in which electrochemical reactions are caused by applying electricalencrgy for the purpose ofrefining or producing materials.
ground: A conducting connection, whether intentional or accidental, between an electric circuit or equipmentand the earth, or to some conducting body that serves in place of earth.
guarded: Covered, shielded, fenced, enclosed, or otherwise protected by means of suitable covers, casing,barriers, rails, screens, mats, or platforms to remove the likelihood of approach or contact by persons or objectsto a point of danger.
insulated: Separated from other conducting surfaces by a dielectric, offering a high resistance to the passageof current.Air space is also a dielectric.
NOTE—When any object is said to be insulated, it is understood to be insulated for the conditions to which it is normallysubjected. Otherwise, it is considered uninsulated, within the purpose of this definition.
isolated: Not readily accessible to persons unless special mcans for access is used.
isolation transformer: A transformer used to electrically separate one circuit from another.
safeguard: A precautionary measure or requirement, or a technical plan to prevent accidents.
work practices for improved safety: Operating and maintenance procedures effective in minimizing the riskof incidents .
3. Description of electrolytic cell lines
Electrolytic cell lines differ widely in size and in physical and clectrical characteristics, even for the sametype process. One cell line may operate at less than 25 V dc and another at more than 2000 v dc dependingon the type and number of cells.Also, one cell line may operate at a few thousand amperes dc and another atover 600 000 A dc.
Electrolytic cell lines may be located indoors or outdoors,may be in a wet or dry environment,may haveconductive or nonconductive floor surfaces, and may be electrically connected to auxiliary equipment such aspumps, motors, piping, and steelwork at elevations above and/or below the cells.
Electrolytic cell linc installations and their associated power sources，clectrical conductors，auxiliaryequipment, and attachments are custom-designed for each installation.
Note that the electrical shock hazard can exist for an extended time period after the cell line rectifiers arede-cnergized.Each clectrolytic cell functions similarly to an clectrical storage battery，which is typicallyreferred to as the “”battery effect.” Due to this battery effect an electrical hazard will exist after the rectifierdc power supply is disconnected.The battery effect will keep the cell line energized with a potential until thechemical reaction in the cell has depleted.
5. Improved safeguarding of personnel from electrical hazards within thecell line working zone
Opcration and maintenance of clectrolytic cell lines routinely requires personnel to contact exposedelectrically energized surfaces such as electrolytic cells, their energized attachments and dc bus. The potentialrisk of injury due to electrical hazards presented by these energized surfaces can be reduced or minimized bythe selection and use of appropriate safeguards.
Exposed energized surfaces of cells and attachments in themselves do not necessarily create electrical hazards.However, simultaneous contact between surfaces operating at different potentials, including ground potential,could create an electrical hazard. Therefore, safeguards shall be provided for personnel performing work taskswithin the cell line working zone.
Safeguards shall be provided by one or a combination of the means described in 5.l through 5.10. In some cellline installations, certain safeguards are inherent due to building size, equipment spacing, component type,materials of construction, etc.