Section 1 General Rules

Selection of conductors for heating, economic current density and corona conditions. Permissible continuous currents for cables with impregnated paper insulation

Encyclopedia of radio electronics and electrical engineering / Rules for the installation of electrical installations (PUE)

Comments on the article

1.3.12. Permissible continuous currents for cables with voltage up to 35 kV with insulation from impregnated cable paper in a lead, aluminum or PVC sheath are taken in accordance with the permissible temperatures of the cable cores:

1.3.13. For cables laid in the ground, the permissible continuous currents are given in Table. 1.3.13, 1.3.16, 1.3.19-1.3.22. They are taken from the calculation of laying in a trench at a depth of 0,7 - 1,0 m no more than one cable at an earth temperature of + 15º C and an earth resistivity of 120 cm K / W. When the earth resistivity differs from 120 cm K / W, it is necessary to apply the correction factors indicated in the table to the current loads indicated in the tables mentioned earlier. 1.3.23.

Table 1.3.13. Permissible continuous current for cables with copper conductors with paper insulation impregnated with oil-rosin and non-drip masses in a lead sheath, laid in the ground

Table 1.3.14. Permissible continuous current for cables with copper conductors with paper insulation impregnated with oil-rosin and non-drip masses in a lead sheath, laid in water

Table 1.3.15. Permissible continuous current for cables with copper conductors with paper insulation impregnated with oil-rosin and non-drip masses in a lead sheath, laid in air

Table 1.3.16. Permissible continuous current for cables with aluminum conductors with paper insulation impregnated with oil-rosin and non-drip masses in lead or aluminum sheath, laid in the ground

Table 1.3.17. Permissible continuous current for cables with aluminum conductors with paper insulation impregnated with oil-rosin and non-drip masses in a lead sheath, laid in water

Table 1.3.18. Permissible continuous current for cables with aluminum conductors with paper insulation impregnated with oil-rosin and non-drip masses in lead or aluminum sheath, laid in air

Table 1.3.19. Permissible continuous current for three-core cables with a voltage of 6 kV with copper conductors with lean-impregnated insulation in a common lead sheath, laid in the ground and air

Table 1.3.20. Permissible continuous current for three-core cables with a voltage of 6 kV with aluminum conductors with lean insulation in a common lead sheath, laid in the ground and air

Table 1.3.21. Permissible continuous current for cables with individually lead-coated copper conductors with paper insulation impregnated with oil-rosin and non-drip masses, laid in the ground, water, air

Table 1.3.22. Permissible continuous current for cables with separately lead-coated aluminum conductors with paper insulation impregnated with oil-rosin and non-drip masses, laid in the ground, water, air

Table 1.3.23. Correction factor for the permissible continuous current for cables laid in the ground, depending on the resistivity of the earth

1.3.14. For cables laid in water, the permissible continuous currents are given in Table. 1.3.14, 1.3.17, 1.3.21, 1.3.22. They are taken from the calculation of the water temperature + 15 º C. 1.3.15. For cables laid in the air, inside and outside buildings, with any number of cables and an air temperature of + 25 º C, the allowable continuous currents are given in Table. 1.3.15, 1.3.18 - 1.3.22, 1.3.24, 1.3.25. 1.3.16. Permissible continuous currents for single cables laid in pipes in the ground should be taken as for the same cables laid in air at a temperature equal to the temperature of the earth. Table 1.3.24. Permissible continuous current for single-core cables with a copper core with paper insulation impregnated with oil rosin and non-drip masses in a lead sheath, unarmoured, laid in air

* The numerator indicates the currents for cables located in the same plane with a clear distance of 35 - 125 mm, and the denominator - for cables located closely in a triangle.

1.3.17. With mixed cable laying, the permissible continuous currents should be taken for the section of the route with the worst cooling conditions, if its length is more than 10 m. It is recommended to use cable inserts of a larger cross section in these cases.

1.3.18. When laying several cables in the ground (including laying in pipes), the permissible continuous currents must be reduced by introducing the coefficients given in Table. 1.3.26. This does not include redundant cables. Laying several cables in the ground with distances between them of less than 10 mm in the clear is not recommended.

1.3.19. For oil- and gas-filled single-core armored cables, as well as other cables of new designs, permissible long-term currents are set by manufacturers.

Table 1.3.25. Permissible continuous current for single-core cables with an aluminum core with paper insulation impregnated with oil-rosin and non-drip masses in a lead or aluminum sheath, unarmoured, laid in air

* The numerator indicates the currents for cables located in the same plane with a clear distance of 35 - 125 mm, the denominator - for cables located closely in a triangle.

Table 1.3.26. Correction factor for the number of working cables lying nearby in the ground (in pipes or without pipes)

1.3.20. Permissible continuous currents for cables laid in blocks should be determined by the empirical formula:

where I_o - permissible continuous current for a three-core cable with a voltage of 10 kV with copper or aluminum conductors, determined according to Table 1.3.27; a - coefficient selected according to the table. 1.3.28 depending on the section and location of the cable in the block; b - coefficient selected depending on the cable voltage:

c - coefficient selected depending on the average daily load of the entire block:

Redundant cables are allowed to be laid in unnumbered channels of the unit if they work when the working cables are disconnected. Table 1.3.27. Permissible continuous current for cables 10 kV with copper or aluminum conductors with a cross section of 95 mm²laid in blocks

Gr.	Block configuration		channel number	Current I0, And for cables
				copper	aluminum
I			1	191	147
II			2	173	133
			3	167	129
III			2	154	119
IV			2	147	113
			3	138	106
V			2	143	110
			3	135	102
			4	131	91
VI			2	140	103
			3	132	104
			4	118	101
VII			2	136	105
			3	132	102
			4	119	92
VIII			2	135	104
			3	124	96
			4	104	80
IX			2	135	104
			3	118	91
			4	100	77
X			2	133	102
			3	116	90
			4	81	62
XI			2	129	99
			3	114	88
			4	79	55

Table 1.3.28. Correction factor per cable section

1.3.21. Permissible continuous currents for cables laid in two parallel blocks of the same configuration must be reduced by multiplying by factors chosen depending on the distance between the blocks:

See other articles Section Rules for the installation of electrical installations (PUE).

Read and write useful comments on this article.

<< Back

Latest news of science and technology, new electronics:

Machine for thinning flowers in gardens 02.05.2024

In modern agriculture, technological progress is developing aimed at increasing the efficiency of plant care processes. The innovative Florix flower thinning machine was presented in Italy, designed to optimize the harvesting stage. This tool is equipped with mobile arms, allowing it to be easily adapted to the needs of the garden. The operator can adjust the speed of the thin wires by controlling them from the tractor cab using a joystick. This approach significantly increases the efficiency of the flower thinning process, providing the possibility of individual adjustment to the specific conditions of the garden, as well as the variety and type of fruit grown in it. After testing the Florix machine for two years on various types of fruit, the results were very encouraging. Farmers such as Filiberto Montanari, who has used a Florix machine for several years, have reported a significant reduction in the time and labor required to thin flowers. ... >>

Advanced Infrared Microscope 02.05.2024

Microscopes play an important role in scientific research, allowing scientists to delve into structures and processes invisible to the eye. However, various microscopy methods have their limitations, and among them was the limitation of resolution when using the infrared range. But the latest achievements of Japanese researchers from the University of Tokyo open up new prospects for studying the microworld. Scientists from the University of Tokyo have unveiled a new microscope that will revolutionize the capabilities of infrared microscopy. This advanced instrument allows you to see the internal structures of living bacteria with amazing clarity on the nanometer scale. Typically, mid-infrared microscopes are limited by low resolution, but the latest development from Japanese researchers overcomes these limitations. According to scientists, the developed microscope allows creating images with a resolution of up to 120 nanometers, which is 30 times higher than the resolution of traditional microscopes. ... >>

Air trap for insects 01.05.2024

Agriculture is one of the key sectors of the economy, and pest control is an integral part of this process. A team of scientists from the Indian Council of Agricultural Research-Central Potato Research Institute (ICAR-CPRI), Shimla, has come up with an innovative solution to this problem - a wind-powered insect air trap. This device addresses the shortcomings of traditional pest control methods by providing real-time insect population data. The trap is powered entirely by wind energy, making it an environmentally friendly solution that requires no power. Its unique design allows monitoring of both harmful and beneficial insects, providing a complete overview of the population in any agricultural area. “By assessing target pests at the right time, we can take necessary measures to control both pests and diseases,” says Kapil ... >>

Random news from the Archive Pocket Photo Printer 15.10.2002 The American company SiPix has released a pocket photo printer. By connecting a digital camera to the printer, you can immediately print the pictures accumulated in its memory about the size of a pocket calendar or smaller, for example, a document. The dimensions of the printer itself are slightly larger than a pack of cigarettes, weight without batteries is 300 grams. Printing one picture takes about 95 seconds. True, those who have tested the new device say that the battery consumption is high, but if you print several pictures, you can use the AC adapter.

Other interesting news:

▪ Glass that generates solar energy

▪ Sneakers with GPS

▪ Interaction between two space-time crystals

▪ paper batteries

▪ Scientists make mistakes

News feed of science and technology, new electronics

Interesting materials of the Free Technical Library:

▪ site section Measuring equipment. Article selection

▪ article Rare bird. Popular expression

▪ article Why do stars emit light? Detailed answer

▪ article Web designer of the Internet marketing department. Job description

▪ FAQ article on speakers and subwoofers. Encyclopedia of radio electronics and electrical engineering

▪ article Charger for multimeter. Encyclopedia of radio electronics and electrical engineering

Leave your comment on this article:

All languages ​​of this page

Arabic	Hebrew	Polish
Bengali	Hindi	Portuguese
Chinese	Italian	Spanish
English	Japanese	Turkish
French	Korean	Ukrainian
German	Malay	Vietnamese

Home page | Library | Articles | Website map | Site Reviews

www.diagram.com.ua
2000-2024