IEEE 384-1981 pdf free.IEEE Standard Criteria forIndependence of Class 1EEquipment and Circuits.
This standard describes the independencerequirements of the circuits and equipmentcomprising or associated with Class 1E systems,including those required for safe shutdown. Itsets forth criteria for the independence thatcan be achieved by physical separation andelectrical isolation of circuits and equipmentwhich are redundant but does not address thedetermination of what is to be consideredredundant.
This standard established the criteria forimplementation of the independence require-ments of IEEE Std 603-1980，[1211 ; ANSI/IEEE Std 279-1971 [3];IEEE Std 308-1980[9]. In addition, this standard provides interimcriteria for implementation of independencerequirements for safeshutdownsystems.
acceptable. Demonstrated to be adequate bythe safety analysis of the station.
associated circuits. Non-Class 1E circuits thatare not physically separated or are not elec-trically isolated from Class 1E circuits byacceptable separation distance，safetyclassstructures, barriers, or isolation devices.
Class 1E.The safetyclassification of theelectric equipment and systems that are essen-tial to emergency reactor shutdown，contain-ment isolation,reactor core coolingandcontainment and reactor heat removal，or areotherwise essential in preventing a significantrelease of radioactive material to the environ-ment.design basis events. Postulated abnormal eventsused in the design to establish the acceptableperformance requirements of the structures,systems, and components.division.The designation applied to a givensystem or set of components that enables theestablishment and maintenance of physical,electrical，and functional independence fromother redundant sets of components.
NOTE:The terms division，train，channel，separationgroup，safety group or load group，when used in thiscontext, are interchangeable.
enclosure.An identifiable housing such as acubicle，compartment，terminal box, panel，orenclosed racewayused for electrical equipment or cables.
exposure fire. Fire initiated by other thanelectrical means or supported by fuel otherthan cable insulation.
flame retardant.Capable of limiting the propa-gation of a fire beyond the area of influence ofthe energy source that initiated the fire.
raceway. Any channel that is designed and usedexpressly for supporting or enclosing wires,cable，or busbars. Raceways consist primarilyof，but are not restricted to，cable trays andconduits.
redundant equipment or system. Equipment orsystem that duplicates the essential function ofanother piece of equipment or system to theextent that either may perform the requiredfunction regardless of the state of operation orfailure of the other.
safety class structures. Structures designed toprotect Class 1E equipment against the effectsof the design basis events.
NOTE: For the purposes of this standard，separatesafety class structures can be separate rooms in thesame building. The rooms may share a common wall.separation distance.Space which has no interposing structures, equipment, or materials thatcould aid in the propagation of fire or thatcould otherwise disable Class 1E systems orequipment.IEEE 384 pdf download.