UF - Single or multi-conductor, with or without ground, used for direct burial underground feeders and branch circuits between buildings, yard lights, floodlights, and similar installations.
UG - The two letter designation that proceeds the number on connectors for coaxial cable. It means Universal Government.
UHF - Abbreviation for ultra high frequency. See frequency band.
UL - Abbreviation for Underwriters Laboratories Inc. A nonprofit organization that maintains and operates laboratories for the examination and testing of devices, systems and materials relative to life, fire and casualty, hazards, and crime prevention. Founded in 1894, the enterprise is sponsored by the National Board of Fire Underwriters.
UL APPROVED - A product that has been tested and approved to Underwriters Laboratories standards.
ULTRA HIGH FREQUENCY - See frequency band. Abbreviation UHF.
UNBALANCED CIRCUIT - A transmission line in which voltage on the two conductors are unequal with respect to ground, e.g., a coaxial cable.
UNILAY CONDUCTOR - A central core surrounded by one or more concentric layers of helically wound strands in a fixed geometrical arrangement with the direction of lay the same for each layer and the central core.
UNSINTERED - Means uncured. This word is usually used to differentiate between cured and uncured PTFE tape.
UNSWEEPT - Coaxial cable that has not had an attenuation check (sweep test).
URC - Nomenclature for weatherproof wire.
USASI - Abbreviation for United States of American Standards Institute. Superseded ASA and in turn was superseded by ANSI.
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