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Special wiring rules apply to wet or corrosive locations, [13] and to locations which present an explosion hazard. [14] Wiring materials for use in the United States must generally be made and tested to product standards set by NEMA and Underwriters Laboratories (UL) and must bear approval marks such as those set by UL.
for AC having a supply frequency of 50, 60 or 400Hz, though the use of other frequencies for special purposes is not excluded. This includes low-voltage installations, as found in most domestic and commercial properties, and extra-low-voltage systems, but excludes high voltage , as found in generation, transmission and distribution networks.
IEC 62128 Railway applications – Fixed installations – Electrical safety, earthing and the return circuit; IEC 62129 Calibration of wavelength/optical frequency measurement instruments; IEC TR 62130 Climatic field data including validation; IEC TR 62131 Environmental conditions – Vibration and shock of electrotechnical equipment
The US National Electrical Code permitted the use of the supply neutral wire as the equipment enclosure connection to ground from 1947 to 1996 for ranges (including separate cooktops and ovens) and from 1953 to 1996 for clothes dryers, whether plug-in or permanently fixed, provided that the circuit originated in the main service panel. Normal ...
The voltage and frequency of electric power differs between regions. In much of the world, a voltage (nominally) of 230 volts and frequency of 50 Hz is used. In North America, the most common combination is 120 V and a frequency of 60 Hz. Other combinations exist, for example, 230 V at 60 Hz.
As frequency gets high enough that the length of the cable becomes a significant fraction of a wavelength, > /, ordinary wires and cables become poor conductors of AC. [ 4 ] : p.12–14 Impedance discontinuities at the source, load, connectors and switches begin to reflect the electromagnetic current waves back toward the source, creating ...
The induction motor was found to work well on frequencies around 50 to 60 Hz, but with the materials available in the 1890s would not work well at a frequency of, say, 133 Hz. There is a fixed relationship between the number of magnetic poles in the induction motor field, the frequency of the alternating current, and the rotation speed; so, a ...
Litz wire is used to make inductors and transformers, especially for high frequency applications where the skin effect is more pronounced and proximity effect can be an even more severe problem. Litz wire is one kind of stranded wire , but, in this case, the reason for its use is not the usual one of avoiding complete wire breakage due to ...