ON THE CRITERION OF DENSITY
Maximum allowable current is the maximum current that can flow continuously and under given conditions a conductor without its temperature exceeding a specified value.- From the cross section of the pipeline
- From the type of insulation
- From the conditions of installation and operation.
According to the ELOT HD384 standard, the values of the maximum permissible currents in electrical lines consisting of conductors with insulation made of Polyvinyl Chloride (PVC), Cross-linked Polyethylene (XLPE) and Ethylene Ethropropylene (EPR) - 52-K2. The values given in the above tables are corrected based on the correction factors of tables 52-D1 and 52-E1 depending on the way the cables are routed and the environmental conditions.For any environmental conditions the values of tables 52-K1, 52-K2 should be multiplied by the correction factors of table 52-D1.The cables are considered to be placed alone in the air or on the ground with adequate ventilation conditions. In any other case of laying the cables in groups or with such a place that they influence each other, the values of tables 52-K1, 52-K2 should be multiplied by the correction factors of table 52-E1.To ensure that the temperature of the conductors does not reach dangerous levels, the current flowing through the conductors must always be less than the maximum permissible current.The process of selecting the cross section of a non-underground conduit or cable consists of the following steps:Step 1: Calculation of the load current Ιφ = P / UsynfStep 2: Determine how the conductor or cable is installed (eg inside a built-in electrical pipe, or in a cable passage grille or directly on the wall, etc.)Step 3: Determine the correction factor D1, depending on the temperature of the installation environment and the pipe insulation material.Step 4: Determine a correction factor E1, for randomly grouped, crowded cables, within the same electrical pipe or distribution channel, either directly on the building material or on the same carrier or in a layer when it is a non-perforated distribution channel.Step 5: Calculate a current Iμ = Iφ / (Ε1 x Δ1)Step 6: From the panels K1 or K2 and depending on the type of installation of the conductor or cable, its insulating and conductive material and the number of active conductors,
the cross-section with current carrying capacity Ιτ> Ιμ is determined.BY CRITERION THE VOLTAGE FALLThe voltage drop occurs in the power supply lines of the consumer appliances because they have a long length. The voltage drop according to the old KEHE was 1% in lighting network and 3% in traffic network. With the power of ELOT HD 384, which is the current KEEE, the allowable voltage drop is 4% for all cases.The relation that gives us the voltage drop in a single-phase line is: ΔU = 2ρ LI syn / sWhere:Voltage drop in Volts.ρ = specific resistance of the conductor in Ω mm / m. For copper ρ = 0,018Ωmm / m.L = the length of the pipeline in m.I = the current flowing through the conductor in amperes.coefficient = the power factor of the load (for lighting coefficient = 1).s = the cross section of the conductor in mm.We check the cross section we calculated if it covers us in terms of voltage drop. If the voltage drop we calculated is less than 9.2 volts we finalize the cross section. If the voltage drop is greater than 9.2 volts we choose the immediately larger one.
the cross-section with current carrying capacity Ιτ> Ιμ is determined.
Example of Pipeline Cross-section Calculation
Example of Pipeline Cross-section Calculation
Panel supplies 7.8 kW power load. The installation will consist of three insulated pipes type H 07V-U or NYA (L, N, PE) 50 meters long, which are placed in a plastic pipe for protection purposes. The pipe is placed under the wall coating. The synchronization coefficient is 100% and the ambient temperature is 40 0 C. Calculate the cross section of the pipes.
Panel supplies 7.8 kW power load. The installation will consist of three insulated pipes type H 07V-U or NYA (L, N, PE) 50 meters long, which are placed in a plastic pipe for protection purposes. The pipe is placed under the wall coating. The synchronization coefficient is 100% and the ambient temperature is 40 0 C. Calculate the cross section of the pipes.
TABLE 52-K2 (ELOT HD-384)
Maximum permissible currents (in A) of power lines with cables in the air (at a distance from walls or other building materials) with PVC or EPR or XLPE insulation.The table mainly concerns the power lines of industrial or similar installations, when these lines consist of cables placed in such a way that the air circulation around them is free.
It concerns electrical lines with single-pole or multi-pole cables, with PVC, EPR, XLPE insulation in which the heat dissipation is not affected by wall or other structural elements. The distance from the nearest wall is greater than or equal to 0.3D, where D is the outside diameter of the line.
Maximum permissible currents (in A) of power lines with cables in the air (at a distance from walls or other building materials) with PVC or EPR or XLPE insulation.
The table mainly concerns the power lines of industrial or similar installations, when these lines consist of cables placed in such a way that the air circulation around them is free.
It concerns electrical lines with single-pole or multi-pole cables, with PVC, EPR, XLPE insulation in which the heat dissipation is not affected by wall or other structural elements. The distance from the nearest wall is greater than or equal to 0.3D, where D is the outside diameter of the line.
BONUS CONTENT
ONLINE CALCULATOR CODE CATEGORY CALCULATOR
* copper resistor 0.0176, allowable voltage drop 4, phase voltage 230V
* copper resistor 0.0176, allowable voltage drop 4, phase voltage 230V
ONLINE CALCULATOR MINIMUM CODE CALCULATOR CALCULATOR - THREE-PHASE CURRENT
* allowable voltage drop 4, polar voltage 400V
* allowable voltage drop 4, polar voltage 400V
