Description of electric wires (part 2)
Hello, dear readers! Today the conversation on conductors, wires and cables will be continued.
Wires are products as you already know, the containing one or several twisted pro-reducing dies or one and more isolated veins, from above which, depending on laying conditions, there is the easy metal cover, the winding and the braid from fibroids or the wire. Wires can be as isolated, and naked.
Naked wires are wires which over conducting veins have no protecting or insulating covers.
Insulated conductors are wires at which conducting veins are covered with isolation, and from above isolation there is the braid from cotton yarn or the cover from plastic, rubber or the metal tape. Insulated conductors can be as protected, and unprotected.
The unprotected wires are the insulated conductors which do not have over electric isolation of the protective cover.
The protected wires are the insulated conductors having over electric isolation the cover which is usually intended for sealing and protection against climatic influences.
Adjusting wires are wires for electrical distribution networks of low tension.
Anywhere and everywhere wires have the alphabetic marking. The example of alphabetic reference of adjusting wires is included below.
Adjusting wires are issued with rubber and molded insulation on tension 380, 660, 3000 V, 50 Hz. Mounting of such wires is allowed at the temperature not below +15 °C. Wires with molded insulation allow long heating of veins to 70 °C, with rubber isolation – to 65 °C, with heatresistant rubber – up to 85 °C, with silicone rubber insulation – up to 180 °C.
Mounting wires are intended for electrical connections of elements of the radio-electronic equipment. They are issued single-core and multicore. They are silver, copper, from stainless steel both to special coverings, and without covering. Apply generally single-core mounting wires in tubular isolation to performance of hinged rigid mounting. As well as everywhere, the section of the mounting wire is chosen depending on current which has to pass on it.
The table of admissible values of current for copper mounting wires
As well as all wires, at them have the alphabetic reference:
For a start it is necessary to give definition what is the cable. The cable is several insulated conductors in the protective hermetic cover. On the hermetic cover of the cable impose several layers of the protective cover protecting the cover from corrosion and mechanical damages.
Except mounting wires, broad application is found by mounting cables with PVC or with polythene insulation and additional protection by the PVC cover. And now it would be desirable to give couple more of definitions.
The power cable is the cable intended for transfer and electric power distribution in lighting and engine electric units for the device of cable lines.
Control cables are the cables intended for chains of control, the alarm system, distance control. Control cables contain from 4 to 37 copper or aluminum veins, with rather small sectional area from 0,75 to 10 mm ², and they can be used for transfer of small power.
They are issued on alternating voltage up to 660 V or constant up to 1000 Century.
Table of use and characteristics of some types of cables
In the domestic market except wires of the USAn production it is possible to get also import analogs. Now in Europe there are in parallel two systems of marking: national and international harmonized. That you could be guided in the choice of the import conductor, the structure of designation on the international system is included below.
Along with new designations apply also old which, according to national norms, begin with the certain letter. For example, N corresponds to Germany (probably, all at least once heard such name as the NYM cable).
Further the table meeting the national German standard is provided. As at the domestic market of conductors there are German products, it is quite possible that these data will be useful to you further.
Cables for information transfer
In addition to electric power transmission, cables are also used for transfer of information signals. Now there were many new types of conductors of information. Not so long ago still there were only telephone and antenna cables, now in connection with development of the various equipment of such cables there was much more. It is necessary to consider briefly those from them which the beginning electrician or the house master has to know and be able to connect.
RG-6 – the coaxial cable for transfer of high-frequency signals for the electronic equipment and television.
Cables of the RG brands have many versions and differ from each other according to some characteristics, for example, on resistance of the conductor, resistance to various loadings, decay time of the signal, the kind of the screen.
Computer cables (twisted pair cable)
Serve for creation of computer networks.
Depending on the type of the cable, different options of protection are possible.
UTP– is unprotected, without the general screen for couples of wires.
FTP– foiled with the screen from aluminum foil.
STP– protected with the general screen from the copper grid, at the same time each twisted pair cable is surrounded with the separate screen.
S/FTP– foiled, screened with the general screen from the foil, each couple is in addition put into the screen.
Besides, twisted pair cables are separated into categories by the number of couples which are united in one cable.Top