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In electrical power distribution, armoured cable usually means steel wire armoured cable (SWA) which 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 11 kV Cable and 33 kV Cable – and is found in underground systems, power networks and cable ducting.
The conduit methods were known to be of better quality, but cost significantly more than K&T. [2] In 1909, flexible armored cable cost about twice as much as K&T, and conduit cost about three times the price of K&T. [6] Knob and tube wiring persisted since it allowed owners to wire a building for electricity at lower cost.
Cables usually are secured with special fittings where they enter electrical apparatus; this may be a simple screw clamp for jacketed cables in a dry location, or a polymer-gasketed cable connector that mechanically engages the armour of an armoured cable and provides a water-resistant connection.
Cables jacketing materials can be formulated to prevent fire spread [4] (see Mineral-insulated copper-clad cable). Alternately, fire spread amongst combustible cables can be prevented by the application of fire retardant coatings directly on the cable exterior, [5] or the fire threat can be isolated by the installation of boxes constructed of ...
It has advantages over armored building cable because it is lighter, easier to handle, and its sheathing is easier to work with. [10] Power cables use stranded copper or aluminum conductors, although small power cables may use solid conductors in sizes of up to 1/0. (For a detailed discussion on copper cables, see: Copper wire and cable.). The ...
Several other types of wiring systems are used for building wiring in the United States; these include corrugated metal armored cable, mineral-insulated cable, other types of power cable, and various types of electrical conduit. In industrial applications cables may be laid in cable trays. Cable type TC is especially intended for use in tray ...
The single-phase colours of red phase and black neutral are replaced by brown phase and blue neutral. These colours have been used in appliance flexible cables since 1969. The cable core colours are described in IEC 60304 (1982-01), Standard colours for insulation for low- frequency cables and wires.
In North American electrical practice, it is available in thirteen different size and wall thicknesses, [4] with the thin-wall variety only suitable for embedded use in concrete, and heavier grades suitable for direct burial and exposed work. Most of the various fittings made for metal conduit are also available in PVC form.