Originally Published IVD Technology June 2003
PROCESSING TECHNOLOGIES
Glossary of Terms|
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Clearance: The shortest distance in the air between two conductive parts.
Creepage: The shortest distance along the surface of the insulating material between two conductive parts.
Hazardous live: The state in which a part can cause an electric shock or electric burn when it is contacted during normal use or a single-fault condition. Hazardous live parts should not be accessible. These parts are considered to be accessible if they can be touched with a test piece (e.g., a finger or pin) or in the absence of a covering that cannot provide suitable insulation. Accessible parts can be prevented from becoming hazardous live through basic insulation, protective impedance, enclosures, and barriers.
Normal condition: The condition in which all means for protection against hazards are intact.
Single-fault condition (SFC): The condition in which one means for protecting against a hazard is defective, or one fault is present which could cause a hazard. Examples of SFC: Failure of components, interruption of protection ground conductor, continuous operation of parts intended for short-term or intermittent operation, locking of moving parts, short circuit and overload, impairment of cooling systems, bridging of insulation between circuits which is below the specified level for basic insulation, leakage of liquids, failure of basic insulation, and incorrect voltage selection.
Working voltage: The highest root-mean-square value of the ac or dc voltage which may occur across the tested insulation.
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