Conditions for placing power cables

 

In case of placement in depth as a single string, the distance of the cable axis to the ground level and in the case of triangular placement, 
the distance of the center of the triangle to the ground level is chosen to be 70 cm. As the depth increases, the allowed flow decreases.
In this case, the temperature and volume resistance of the earth are considered the same. Normal working conditions are listed in the table below:
Being in the air
- A multi-core cable
- A single strand cable in direct current system
- Three single-stranded cables in a three-phase system next to each other and at a distance of one cable diameter from each other
- Three single-stranded cables in a three-phase system as a bundle (1)
- Placement in the open air, for example: maintaining a distance of at least 2 cm from the wall, floor or ceiling to prevent thermal radiation
- For cables that are next to each other: a minimum distance of twice the diameter of the cable
- For cables that are on top of each other: at intervals of at least 30 cm of cable length, the minimum vertical distance of the cables from each 
other is twice the diameter of the cable.
- Cable heat loss considerations:

If the air temperature increases, the places should be large enough and have a ventilation system.

- Protection from direct sunlight, etc
- Metal covers or shields should be connected to the ground at both ends of the cable.
Placement on the ground
- A multi-core cable
- A single strand cable in direct current system
- Three single-stranded cables in a three-phase system next to each other and at a distance of 7 cm
- Three single-stranded cables in a three-phase system as a bundle (1)
- Placing in sand or soil and, if necessary, covered with bricks, cement or a light layer of flat or slightly curved plastic
Environmental conditions

- Ground temperature in deep installation: 20 degrees Celsius
- Thermal resistance of soil in wet areas:
1°K.m/W
- Thermal resistance of soil in dry areas:
2.5°K.m/W
- Metal covers or shields should be connected to the ground at both ends of the cable.
(1) in groups or in triangular contact


 

 
 
 
 
 
 
 
 
 
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