Wire and Cable - A Basic Primer

By Robert Cong

Taking a cable and connecting one point of contact to the other may seem easy enough, but many people don't understand all the different properties associated with wire and cable in order to maximize the connectivity and data delivery. Whether used for circuit prototyping, Ethernet connectivity or transmitting 1000V from one county to another, wire and cableing are a very important part of our everyday lives.

When you think of the material used in wiring, the first thought is usually copper. Copper is a great electrical conductor and was fairly inexpensive when the demand began to rise in the 1800s after the invention of the telephone and advances in generation and transmission of AC and DC current. Although some may argue there are better conductors such as gold and silver, copper is still the best conductor and remains the most economical solution, even better than aluminum, which explains why almost every wire product sold contains copper.

Here are some variations of wire products, each with its own properties for a specific job.

Solid Hook-up Wire

Solid Hook-Up Wire

Single strand of insulated copper wire. It is not very flexible and typically is used as magnet wire in transformers and motors. Great for prototyping on a breadboard.

Stranded Hook-Up Wire

Stranded Hook-up Wire A bundle of thin copper wires twisted or braided together, the stranded variety improves the life of the wire in high-vibration applications. Stranded hook-up wire is flexible and perfect for use in small, tight spaces.

Coaxial Cable

Coaxial Cable Coaxial cable is composed of a solid copper core with a tubular insulating layer, surrounded by a tubular conducting shield and then by a plastic jacket. Coax is mainly used for radio frequency signals that require protection from electromagnetic interference (EMI).

Network Cable

Network Cable Network cable includes coaxial, CAT6 and fiber optic cables. These are mainly used for connecting devices and transferring data communication at high speeds. Network cable commonly comes in twisted pairs in order to cancel out EMI.

Computer Cable

Computer cable includes ribbon, USB, ATX, extension cables, and more. It is used to connect the various components of a computer, which require compact flexibility. Ribbon cables, in particular, are made of many conducting stranded wires running parallel to each other.

A Few Codes, Approvals and Recognitions

UL1007 / UL1569: Almost all hook-up wire contains this rating. UL1007 deems the wire with a safe operating temperature of up to 80°C (176°F) and 300V, while UL1569 deems it with a safe operating temperature of up to 105°C (221°F) and 300V.

UL1423: Wire insulated with extruded PVDF (polyvinylidene fluoride). Notably for use in kynar wire and back panel areas such as computers, network stations and business machines.

UL94V: Flammability standard for plastics, subject to the connectors on cables. Defines the plastic's burn characteristics in various settings.

ULVW-1: Vertical wire flame test, which tests the material's ability to resist fire along a vertically suspended wire. Significantly reduces the risk of fire due to the wire or cable and its materials.

MIL-C: Applies to military-grade cables and components to define the electrical and mechanical requirements and the standards of attenuation and structural return loss.

CL2 / CL3: Codes for wiring, usually associated with audio cables and speaker wire, that determine whether or not they can be installed in-wall or other specific locations. Requirements depend on local laws and certain types of homes.

Power Cords

SVT (Service Vacuum Thermoplastic): Applies to two or three conductors with rubber insulation and plastic jacket. 300V rating.

SJT (Service Junior Thermoplastic): Applies to two, three or four conductors with plastic insulation and plastic jacket. 300V rating.

SPT-2 (Service Parallel Thermoplastic) 2/64" Insulation: Applies to two or three conductors with plastic insulation and no jacket. 300V rating.

Wiring code and approval definitions

When it comes to wiring homes and buildings, a certain number of strict regulations must be put in place in order to keep up with safety standards, so make sure you comply with your local laws.

Robert is a graduate from Cal Poly, San Luis Obispo in Electrical Engineering. His interests include sports, movies, music and playing with cool, new gadgets.