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The Book of Terms

The Book of TermsThe WJI Book of Wire & Cable Terms: an interactive experience of learning and sharing
This book, written by industry volunteers and containing more than 5,000 entries, is an asset for newcomers to wire and cable.

At the same time, it also represents an opportunity for industry veterans to give back by either updating or adding to the more than 5,000 entries. This is an honor system process. Entries/updates must be non-commercial, and any deemed not to be so will be removed. Share your expertise as part of this legacy project to help those who will follow. Purchase a printed copy here.


 

All   0-9   A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

Underdraft

1) In wiredrawing, too little reduction in a particular die will result in “skin brittleness” of the drawn wire due to lack of working the entire cross-section. 2) The tendency of metal to curve downward when leaving rolls because of the slower surface speed of the lower roll.

Underfill

1) A cross section that has not filled up the roll pass so that it is inaccurate in both shape and dimensions. 2) A portion of a forged part that does not have sufficient material to give it the true shape of the impression.

Underground Cables

These cables (type USE) are suitable for direct burial to complete the circuit from a utility source to a customer’s meter. They are available as single conductor, multiple conductor and multiple conductor with an outer jacket. All single conductors and multiple conductor cables without jackets must be protected by conduit upon emerging from the earth. Use with an outer jacket may be installed as type SE cable.

Underground Distribution

Refers to “direct burial” (DB) distribution systems. Pluses: minimizes damage from storms, motor vehicles, fires and foreign objects. Minuses: subject to disruption from accidental digging, leakage of moisture and from certain major natural disasters, such as floods.

Underground Exchange Cables

Cables for communication exchanges that are used underground and developed with proper insulation and moisture proof jacketing.

Underground Transmission

The ability to transmit power underground at a higher voltage, using a pipe-type cable. The cable, which has either a copper or aluminum conductor insulated by layers of oil-impregnated paper tape, is pulled through a coated steel pipe that is then filled with an insulating oil or gas. The electrical capacity of the cable can be increased by force cooling using heat exchangers and pumps to circulate and cool the oil contained within the pipe. In addition, there is a technique of using compressed gas as an insulating medium inside aluminum pipe.

Undervoltage

Less than normal operating voltage. Usually the result of inadequate wire size for the length of the circuit.

Ungrounded

Not connected to the earth. In some situations “ungrounding” is intentional as part of the circuit. In other cases where the lack of a ground is unintentional, a safety hazard to equipment and personnel exists.

Unidirectional Concentric Stranding

Stranding where each successive layer has a different lay length thereby retaining a circular form without migration of strands from one layer to another.

Unidirectional Conductor

Conductor constructed with a central core surrounded by more than one layer of helically laid wires, with all layers having a common direction of lay, with an increase in length of lay for each successive layer.

Unidirectional Stranding

A term denoting that, in a stranded conductor, all layers have the same direction of lay.

Uniform Strain

1) The strain occurring prior to the beginning of localization of strain (necking). 2) The strain at the maximum load in the tension test.

Unilay

A conductor with more than one layer of helically laid wires with the direction of lay and length of lay the same for all layers.

Unilay Conductor

A conductor constructed with a central core surrounded by more than one layer of helically laid wires, with all layers having a common length and direction of lay.

United States Steel Wire Gauge

A name sometimes applied to Steel Wire Gauge (Washburn & Moen Gauge) to distinguish it from the Standard Wire Gauge.

Units, Conductors

The grouping of twinned conductors used in forming a cable. Usually 25 pairs. The units may be divided into such units of 12 and 13 pairs or 8, 8 and 9 pairs.

Unloading Unit

A spoon-type receiving tray located at the end of a conveyor. It is synchronized with the movement of the conveyor to transfer the coil to one arm of the capstan, which is then rotated to present the coil on loading station.

Unsintered

Uncured. This word is often used to differentiate between cured and uncured Teflon® tape.

Upender, Coil

A device that puts a coil in the vertical position, suitable for pick-up by an overhead conveyor hook.

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