A cable is most often two or more wires running side by side and bonded, twisted or braided together to form a single assembly, but can also refer to a heavy strong rope. In mechanics cables, otherwise known as wire ropes, are used for lifting, hauling and towing or conveying force through tension. In electrical engineering cables are used to carry electric currents. An optical cable contains one or more optical fibers in a protective jacket that supports the fibers.

Electric cables discussed here are mainly meant for installation in buildings and industrial sites. For power transmission at distances greater than a few kilometres see high-voltage cable, power cables and HVDC.

History

Ropes made of multiple strands of natural fibers such as hemp, sisal, manila, and cotton have been used for millennia for hoisting and hauling. By the 19th century, deepening of mines and construction of large ships increased demand for stronger cables. Invention of improved steelmaking techniques made high-quality steel available at lower cost, and so wire ropes became common in mining and other industrial applications. By the middle of the 19th century, manufacture of large submarine telegraph cables was done using machines similar to those used for manufacture of mechanical cables.

In the 19th century and early 20th century, electrical cable was often insulated using cloth, rubber and paper. Plastic materials are generally used today, except for high-reliability power cables.

Electrical cables

Electrical cables may be made more flexible by stranding the wires. In this process, smaller individual wires are twisted or braided together to produce larger wires that are more flexible than solid wires of similar size. Bunching small wires before concentric stranding adds the most flexibility. Copper wires in a cable may be bare, or they may be plated with a thin layer of another metal, most often tin but sometimes gold, silver or some other material. Tin, gold, and silver are much less prone to oxidation than copper, which may lengthen wire life, and makes soldering easier. Tinning is also used to provide lubrication between strands. Tinning was used to help removal of rubber insulation. Tight lays during stranding makes the cable extensible (CBA - as in telephone handset cords).

Cables can be securely fastened and organized, such as by using trunking, cable trays, cable ties or cable lacing. Continuous-flex or flexible cables used in moving applications within cable carriers can be secured using strain relief devices or cable ties.

At high frequencies, current tends to run along the surface of the conductor. This is known as the skin effect.

Cables and electromagnetic fields

Any current-carrying conductor, including a cable, radiates an electromagnetic field. Likewise, any conductor or cable will pick up energy from any existing electromagnetic field around it. These effects are often undesirable, in the first case amounting to unwanted transmission of energy which may adversely affect nearby equipment or other parts of the same piece of equipment; and in the second case, unwanted pickup of noise which may mask the desired signal being carried by the cable, or, if the cable is carrying power supply or control voltages, pollute them to such an extent as to cause equipment malfunction.

The first solution to these problems is to keep cable lengths in buildings short, since pick up and transmission are essentially proportional to the length of the cable. The second solution is to route cables away from trouble. Beyond this, there are particular cable designs that minimize electromagnetic pickup and transmission. Three of the principal design techniques are shielding, coaxial geometry, and twisted-pair geometry.

Shielding makes use of the electrical principle of the Faraday cage. The cable is encased for its entire length in foil or wire mesh. All wires running inside this shielding layer will be to a large extent decoupled from external electric fields, particularly if the shield is connected to a point of constant voltage, such as earth. Simple shielding of this type is not greatly effective against low-frequency magnetic fields, however - such as magnetic "hum" from a nearby power transformer. A grounded shield on cables operating at 2.5 kV or more gathers leakage current and capacitive current, protecting people from electric shock and equalizing stress on the cable insulation.

Coaxial design helps to further reduce low-frequency magnetic transmission and pickup. In this design the foil or mesh shield has a circular cross section and the inner conductor is exactly at its center. This causes the voltages induced by a magnetic field between the shield and the core conductor to consist of two nearly equal magnitudes which cancel each other.

A twisted pair has two wires of a cable twisted around each other. This can be demonstrated by putting one end of a pair of wires in a hand drill and turning while maintaining moderate tension on the line. Where the interfering signal has a wave length that is long compared to the pitch of the twisted pair, alternate lengths of wires develop opposing voltages, tending to cancel the effect of the interference.

Fire protection

In building construction, electrical cable jacket material is a potential source of fuel for fires. To limit the spread of fire along cable jacketing, one may use cable coating materials or one may use cables with jacketing that is inherently fire retardant. The plastic covering on some metal clad cables may be stripped off at installation to reduce the fuel source for fires. Inorganic coatings and boxes around cables safeguard the adjacent areas from the fire threat associated with unprotected cable jacketing. However, this fire protection also traps heat generated from conductor losses, so the protection must be thin.

There are two methods of providing fire protection to a cable:

#Insulation material is deliberately added with fire retardant materials #The copper conductor itself is covered with mineral insulation (MICC cables)

Electrical cable types

Basic cable types are as follows:

;Shape

Ribbon cable

;Construction Based on construction and cable properties, they can be sorted into the following:

Coaxial cable

Mineral-insulated copper-clad cable

Twinax cable

Flexible cables

Non-metallic sheathed cable (or nonmetallic building wire, NM, NM-B) Metallic sheathed cable (or armored cable, AC, or BX)

Multicore cable (consist of more than one wire and is covered by cable jacket)

Shielded cable

Single cable (from time to time this name is used for wire)

Twisted pair

Twisting cable

;Special

Arresting cable

Bowden cable

Heliax cable

Direct-buried cable

Heavy-lift cable

Elevator cable

Application

Audiovisual cable

Bowden cable for bicycle

Communications cable

Computer cable

Mechanical cable

Sensing cable

Submersible cable

Wire rope (wire cable)

See also

For transmission see: Power cable, High-voltage cable and HVDC

Cable dressing

Cable gland

Cable harness

Cable lacing

Cable length

Cable management

Cable modem

Cable reel

Cable television

Cable tray

Category 5 cable

Category 6 cable

Category 7 cable

Circuit integrity

Copper wire and cable

Cross-linked polyethylene

DOCSIS

Electrical connector

Electrical wiring

Extension cable

International Cablemakers Federation

Over/under cable coiling

Polyvinyl chloride

Portable cord

Power cable

Profibus

Submarine communications cable

Submarine power cable

Steel Wire Armoured (SWA) Cable

SY control cable

Tensile structure

Transmission line

Wire

Wire rope

References

Further reading

R. M. Black, ''The History of Electric Wires and Cables'', Peter Pergrinus, London 1983 ISBN 0-86341-001-4

BICC Cables Ltd, "Electric Cables Handbook", WileyBlackwell; London 3rd Edition edition 1997, ISBN 0-632-04075-0

External links

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Jonathan Goldman is an author, musician and teacher in the fields of Harmonics and ''Sound Healing''. He is based in Boulder, Colorado and his career spans over 30 years.

Background

Goldman's interest in using sound as a healing modality originated from his own experiences during live performances as a guitarist in the Boston punk scene in the late 1970s. While playing, he became aware of how sound could be made to affect listeners, determined, in part, by the intention of the musician, not just the physical act of playing an instrument, nor the emotional energy expressed by the musician while playing. Based on these experiences, Goldman began to research the science of sound and music psychology, directing his overall studies towards the use of sound as a healing force.

His research and desire to connect with like-minded people led to his founding of the Sound Healers Association (SHA) in Lexington, MA in 1982. SHA was a small, informal gathering of musicians, artists, scientists, teachers and authors, and anyone interested in sound healing. Meetings were organized by Goldman; they were held in his home once a month and typically included a guest speaker's presentation, followed by a Q&A. Guest speakers included Steven Halpern, John Beaulieu, Randall McClellan and Dr. Peter Guy Manners. Subjects discussed at SHA meetings included the work of Hans Jenny; Resonance; Musica universalis; Harmonics and Entrainment.

During this time, Goldman worked on his Master's Degree program in Independent Study from Lesley University, researching the Uses of Sound and Music for Healing. This work would later become the main source of material for his first published works. He also began recording his own music and he formed Spirit Music, one of the first record labels dedicated to the therapeutic use of sound and music. Spirit Music has recorded and released music by Goldman, as well as Don Campbell, Sarah Benson, Sam McClellan, Laraaji, the Gyume Monks and more recently, Lama Tashi, among others.

Goldman's healing music and writing has been heavily influenced by the early SHA meetings as well as mythology; psychology; multi-cultural music traditions; ancient religions; mathematics and speculative fiction. In short, Goldman has a three-part theory that runs beneath all of his written and music works:

# That everything in the universe is in a state of vibration. Everything is in motion and produces a sound or frequency. This includes the various parts of our body, organs, bones, tissue, etc. # When we are in a state of "sound" health, everything in our bodies is vibrating in resonance or harmony with itself. When something is vibrating out of harmony, we call this "disease". # Sound is an energy that can entrain or change the vibrational rate of objects. Therefore, if something is vibrating out of tune or harmony, it is possible to create the correct, natural "resonant" frequency of the out of tune object, project it to that out of tune portion and cause it to vibrate back to its normal, healthy state. This, in turn, can be summarized as: Frequency + Intent = Healing.

Connection to Tibetan Buddhism

During his research, Goldman worked with the Gyume Monks, whose sacred chanting of ancient mantras is said to be encoded with healing properties and to be of great benefit to its listeners. Goldman met and became a student of the monks during their 1988 US Tour. During this time, Goldman recorded and produced a concert of the Gyume Monks' chanting, and he learned the art of deep voice chanting and the 'One Voice Chord' technique from the monks.

He later went on to meet the Tibetan Buddhist Monk, Rinchen Chugyal, then Chant Master for the Drepung Loseling Monastery. In 1995 Rinchen Chugyal ordained Goldman as a Chant Master, empowering him to teach Tibetan Chanting in the West. Goldman also met and became close to the aforementioned Venerable Ngawang Tashi Bapu (Lama Tashi), who followed Rinchen Chugyal to become Chant Master of Drepung Loseling Monastery. Lama Tashi recorded several sessions of Tibetan chanting with Goldman. His 'Tibetan Master Chants', recorded and produced by Goldman, was nominated for a Grammy Award in 2004.

Goldman's chanting has been featured on several recordings, notably the 1999 Grammy Award winning album by Kitaro, 'Thinking of You'; his own 'Chakra Chants' series; 'Chakra Dance', which was produced for the opening of a holistic dance club in New York City, and 'Medicine Buddha', made for the US teachings of HH Dalai Lama in 2001.

Teachings

Goldman produces and hosts an annual 'Healing Sounds Intensive' course in Loveland, CO. He also hosts private clinics for small groups or individuals. He has lectured and taught internationally at major sound conferences and health expos, including National Music & Health Conference, Harvard University, Wesak Festival, American Association of Music Therapy Conference, Tufts University, Global Sound Conference and the University of Hawaii. He also is the presenter of a monthly online radio show on www.healthylife.net.

Discography & Bibliography

As of May 2010, there are over 30 albums of Jonathan Goldman's own music released on Spirit Music and other labels. His music has ranged from New Age, Chanting, Ambient, Minimalist, to Techno as well as music intended to be played during specific activities such as meditation, reiki yoga and massage. In 2011 Jonathan Goldman was inducted into the Massage Therapy Hall of Fame.

As of May 2011 Goldman has written six books in the field of sound healing which have been published. Four of Goldman's books have been published in numerous languages and are Best Sellers.

Goldman continues to work out of his private recording studio, Spirit Studios, which is located in his home in Boulder, CO.

Discography

! Year	! Title	! Label
1990	Dolphin Dreams	Spirit Music
1991	Gateways: Men's Drumming and Chanting	Spirit Music
1991	Angel of Sound	Spirit Music
1991	Trance Tara	Spirit Music
1992	Song of Saraswati	Spirit Music
1992	Sacred Gateways	Spirit Music
1994	The Angel and the Goddess	Spirit Music
1995	Celestial Reiki	Spirit Music
1998	The Lost Chord	Etherean Music
1999	Chakra Chants	Spirit Music
2000	Celestial Yoga	Spirit Music
2001	Medicine Buddha	Spirit Music
2001	Celestial Reiki	Spirit Music
2002	Ultimate Om	Spirit Music
2002	Holy Harmony	Spirit Music
2003	Healing Sounds DVD	Spirit Music
2004	Chakra Dance	Spirit Music
2004	Chakra Chants 2	Spirit Music
2004	Celestial Reiki II	Spirit Music
2005	Healing Sounds	Spirit Music
2005	Vocal Toning the Chakras	Sounds True
2005	Tantra of Sound Harmonizer w/Andi Goldman	Spirit Music
2005	Frequencies: Sounds of Healing	Spirit Music
2005	The Divine Name w/Gregg Braden	Spirit Music
2006	Reiki Chants	Spirit Music
2007	De-stress	Spirit Music
2007	Waves of Light	Spirit Music
2008	2012: Ascension Harmonics	Spirit Music
2009	Crystal Bowls Chakra Chants	Spirit Music
2010	2013: Ecstatic Sonics	Spirit Music

Bibliography

! Year	! Title	! Publisher
1992	Healing Sounds: The Power of Harmonics	Healing Arts Press
1998	Shifting Frequencies	Light Technology Publications
1999	The Lost Chord	Spirit Music, Inc.
2005	Tantra of Sound	Hampton Roads Publishing
2008	The 7 Secrets of Sound Healing	Hay House
2010	The Divine Name: The Sound That Can Change the World	Hay House

Personal life

Goldman grew up in New Jersey, at a family-owned Kosher hotel. Many celebrities at the time performed there including Jackie Mason and Rodney Dangerfield. Henny Youngman performed at Goldman's bar mitzvah.

Goldman's father, Irving B. Goldman was a pioneer in the field of Ear, Nose and Throat. His patients included Dean Martin and Frank Sinatra. Goldman's brother is a dermotologist to the stars in Beverly Hills, who has treated many luminaries of Hollywood, including Frank Sinatra.

His wife, Andi Goldman, is a licensed therapist and was one of the first therapists in the US to adopt a phone-in service for patients in crisis.

References

External links

Sound Healers Association

Jonathan Goldman's Healing Sounds

[ Discography at www.allmusic.com]

The Power of Music

Category:Ambient musicians Category:American writers Category:American musicians Category:Living people Category:New Age writers Category:New Age musicians Category:Tibetan Buddhism Category:Year of birth missing (living people)