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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


A designation for a type of shielded power cable. Multi-conductor cables have paper or varnished-cambric insulation applied directly over individual conductors. Spiraled metallic shielding tape over insulation with overall protective covering.

H Wire

Letter used in coding building wire based on the parameter that the wire has high heat resistance.


Alloy steels that possess specifically established hardenability.

H-Type Cable

A screened cable.

Half Wave

Rectifying only half of a sinusoidal AC supply.


A temper resulting from cold rolling or drawing to produce a tensile strength about midway between dead soft and full hard tempers.

Half-Hard Point

A method used for annealability testing that uses a tensile strength-annealing temperature curve for standard reduction and annealing cycle. The annealed strength is determined by a calculated length of time at an elevated temperature. The half-hard point is arbitrarily assumed as being the softening temperature and is obtained graphically.v

Hall Effect

The changing of current density in a conductor due to a magnetic field extraneous to the conductor.


The most commonly occurring halogens in cable compounds are fluorine, chlorine and bromine. Polymers or additives containing these elements can impart desirable flame retardant properties. Halogens are an inherent part of halogenated polymers by being included into the polymer composition on a molecular scale. Additives containing halogens can be incorporated into both halogenated and non-halogenated polymers to enhance flame retardant properties. The potential for some halogenated materials to release acidic gasses and/or high levels of smoke in a fire situation should be balanced against flammability requirements as measured by an appropriate flammability test. Typical halogenated polymers used in wire and cable applications are polyvinyl chloride (PVC), chlorinated polyethylene (CPE), chlorsulfonated polyethylene (CSPE), and fluoropolymers.

Halogen Free

Flame retardant materials that do not contain halogens as part of their inherent (molecular) composition or as flame retardant additives are defined as halogen free. Halogen-free additives are used most often to impact flame retardance to polyolefin-based polymers that are not inherently flame retardant. Commonly used halogen-free additives are aluminum trihydrate, magnesium hydroxide and phosphorous-containing compounds. Halogen-free materials may be specified when a low risk of release of halogenated species is desired in a fire situation with respect to smoke, corrosivity or environmental impact.

Hammer Lap

A defect on the surface of the steel that is a folded-over portion produced by bad practice in forging.


This term, which normally is used as either left-hand or right-hand, refers to the direction in which the helix of a spring is formed. Also used to indicate the helix direction of wires during stranding.

Hand Straightening

The process of straightening by bending or twisting by hand with the aid of adjustable supports and suitable hand tools.


A small box in a raceway used to facilitate cable installation into which an installer can reach but not enter.

Hard Drawn

A temper produced in wire, rod or tube by cold drawing. Hard drawn refers to the temper of wires that are drawn without annealing and work harden in the drawing process. Also, wire that has been drawn to a specific size without being annealed.

Hard Water Soaps

The use of hard water results in the formation of hard water soaps or curds similar to those in a bathtub ring. They create the same problems as other soaps in the system. Hard water is often defined as a liquid that contains over 100 ppm of calcium and/or magnesium.

Hard Wire System

Cable connection using either screw lugs or a splice.

Hard-Laid Rope

Rope formed from large wires. Also known as coarse laid.


The property that determines the depth and distribution of hardness of a metal induced by quenching. Increased hardenability results in deeper hardening, or the achievement of a given hardness with a less rapid quenching rate. The ability of a metal to react to a hardening heat treatment as measured by surface hardness and the depth of hardening below the surface.


Increasing the hardness of steel by heat treatment. The steel is heated to a suitable austenitizing temperature, holding at that temperature for a sufficient time to affect the desired solution of carbon and other alloying elements, then quenching in a suitable medium, such as water, oil, air, polymer or molten salts to form martensite.

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