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Galvanised Steel Wire vs Strip Cable Armor

09/25/2011 10:48 AM

First time here. What is the criteria for deciding whether to use GI wire armoring or GI strip armoring for 11KV 3Core cables ?

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#1

Re: Galvanised Steel Wire vs Strip Cable Armor

09/25/2011 11:44 AM

Unfortunately, you cannot select that. In cables, where the fictitious diameter over the innersheath does not exceed13mm, the armour consists of galvanised round steel wires; above this size, normally the armour is of galvanised formed steel strips.

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#2
In reply to #1

Re: Galvanised Steel Wire vs Strip Cable Armor

09/25/2011 10:02 PM

Thanks but just to put the Q in a different view... is there any specific purpose for which 11KV 3Core cables are wire armored ?

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#4
In reply to #2

Re: Galvanised Steel Wire vs Strip Cable Armor

09/25/2011 11:34 PM

It is armored to provide mechanical protection. Hence the name, "armor"

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#3
In reply to #1

Re: Galvanised Steel Wire vs Strip Cable Armor

09/25/2011 11:18 PM

Is there any convention to use one kind of armour for LV and another kind for MV/HV cables?. Was there any change in practice between 1950s,60s and 2000 or between BS,NEC,VDE etc?.

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#5
In reply to #3

Re: Galvanised Steel Wire vs Strip Cable Armor

09/25/2011 11:43 PM

Are there any history majors around?

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#6

Re: Galvanised Steel Wire vs Strip Cable Armor

09/26/2011 12:28 AM
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#7

Re: Galvanised Steel Wire vs Strip Cable Armor

09/26/2011 12:34 AM

Why the cables needs to be armored? Say SWA armored cables?

Steel Wire Armoured Cable, commonly abbreviated as SWA, is a hard-wearing power cable designed for the supply of mains electricity. It is one of a number of armoured electrical cables - which include 11kV Cable and 33kV Cable - and is found in underground systems, power networks and cable ducting.[1]

The typical construction of an SWA Cable can be broken down as follows:

  • Conductor: consists of plain stranded copper (cables are classified to indicate the degree of flexibility. Class 2 refers to rigid stranded copper conductors as stipulated by British Standard BS EN 60228:2005[2])
  • Insulation: Cross-linked polyethylene (XLPE) is used in a number of power cables because it has good water resistance and excellent electrical properties. Insulation in cables ensures that conductors and other metal substances do not come into contact with each other.[3]
  • Bedding: Polyvinyl chloride (PVC) bedding is used to provide a protective boundary between inner and outer layers of the cable.
  • Armour: Steel wire armour provides mechanical protection, which means the cable can withstand higher stresses, be buried directly and used in external or underground projects.[4] The armouring is normally connected to earth and can also be used as the circuit protective conductor ("earth wire") for the equipment supplied by cable.
  • Sheath: a black PVC sheath holds all components of the cable together and provides additional protection from external stresses.

The PVC version of SWA Cable,[5] described above, meets the requirements of both British Standard BS5467[6] and International Electrotechnical Commission standard IEC 60502.[7] It is known as SWA BS5467 Cable and it has a voltage rating of 600/1000V.[8]

SWA Cable can be referred to more generally as Mains Cable, Armoured Cable, Power Cable and Booklet Armoured Cable. The name Power Cable, however, applies to a wide range of cables including 6381Y, NYCY, NYY-J and 6491X Cable.

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#8

Re: Galvanised Steel Wire vs Strip Cable Armor

09/26/2011 1:53 AM

Thank you all.. I think what is being discussed is whether armor is required and mechanial properties etc. Kindly inform whether there is any specific reason why wire armoring is used instead of GI strip armoring for 3C , 11KV cables

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#9
In reply to #8

Re: Galvanised Steel Wire vs Strip Cable Armor

09/26/2011 2:55 AM

What we need is under what circumstances(voltage,insulation,conductor size,current rating,conductor/cable diameter,soil conditions,temperature of soil,EM shielding , resistance/inductance of armour etc) each of these two kinds of armour is recommended?. Or the advantages and disadvantages of each kind of armour?.

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