2023 Author: Philip Bishop | [email protected]. Last modified: 2023-05-24 22:24
- Division of electrical wiring into groups
- Method for calculating electrical power
- Table for calculating the required wire section depending on the load
- Table of power, current and cross-section of cable and conductor materials
In every modern apartment, country house or cottage, household appliances and engineering equipment are installed that consume a large amount of electricity. In the science of electrical phenomena, the use of electricity for practical purposes, it is customary to call such consumers loads. It will help to improve the convenience of using the electrical network, a competent division into groups of electrical wiring in an apartment with an input voltage of 380 or 220 volts.
Division of electrical wiring into groups
Due to the use in housing of a large number of such electrical appliances as washing machines, air conditioners, boilers, various audio and video equipment, the load on modern electrical wiring has increased. The kitchen area ranks first in the house for the concentration of household appliances - an electric stove, refrigerator, microwave oven, dishwasher, double boiler, electric kettle and many additional appliances that consume a large amount of electricity.
For example, a three-phase input (380 V) and to avoid overload on it, all phases must be evenly distributed. Otherwise, the voltage on the phase wires will differ upward or downward. In the case when there is a single-phase power supply equal to 220 V with voltage drops in the range from 150 to 280 V, it can lead to damage to electrical appliances.
Also, with such work, there is an increase in electricity consumption for equipment that is not protected from voltage drops in the network. Therefore, it is very important to correctly distribute the loads in phases.
To distribute the load and provide protection and safety during operation, electrical wiring is divided into groups. This method will allow you to separately control the supply of current to individual devices or a set of electrical consumers. This method is convenient when carrying out repair work, since you can turn off the desired power supply group. In various emergency situations, neighbors flooded, a nail was unsuccessfully hammered into the wall, which damaged the wiring. After disconnecting the emergency unit, you can continue to use the remaining lines.
- Large household appliances, which act as powerful energy consumers, are installed separately with the installation of a circuit breaker in the distribution box. This technique is an electric stove, an electric oven, an electric kettle, a water heater, an air conditioner, a washing machine.
- A group of sockets, each room is a living room, bedroom, nursery, office, it is recommended to make individual blocks.
- The kitchen is a very busy part of any home, where the sockets must also be separated.
- The lighting system is made by an individual unit, if possible, it is better to make the lighting of each room separately.
- The sanitary unit, which is included in the point of the most dangerous premises according to the electrical safety system, where there is high humidity, must also be performed by a separate group.
Before you start dividing the wiring into groups, you should draw up a plan of the room with the marked locations of sockets and powerful household appliances, lamps, switches. Knowing in advance which electrical connection points will be involved, you can avoid reworking the wiring in the future.
The set of outlets and lighting fixtures is calculated from the electrical load for this row. In the case when the power of all connected units exceeds the norm permissible for this system, the unit is divided into two or, if necessary, more lines.
In rooms with a high level of humidity, a differential protection for leakage current of 10 mA is installed. The most suitable devices for installation are a circuit breaker in combination with an RCD or a complex protective device that performs the protective functions of two devices. It will allow you to protect the supplied circuit from overloads, short-circuit currents such combinations of cables with automatic devices:
- For other lines, a 30 mA differential protection system is installed.
- Lighting is carried out with a cable with a cross-section of 3x1.5 mm2, protection by an automatic 10 A.
- It is better to make the sockets with a 3x2.5 mm2 cable and a 16 amp circuit breaker protection.
- Consumers with a power of more than 3.5 kW - electric ovens, electric stoves must be connected directly to the electric cable with the installation of a circuit breaker of the required rating.
With an online calculator, calculate the wire cross-section.
Choose circuit breakers and cross-section, the supply wires should be in the more loaded phase. The uneven distribution of the phase load and unaccounted for asymmetries in the distribution of the current load lead to serious errors in the selection of wire cross-sections, which leads to an overload of the electrical system - overheating, breakdown, risk of ignition. When buying an electrical cable, it is recommended to choose wires with fire safety indicators
In detail, about the installation of the flat panel.
Method for calculating electrical power
For distribution by groups of electrical wiring when designing electrical network circuits in apartments, country houses, cottages, summer cottages and other small objects, in which the voltage does not exceed 15-25 units. An elementary and efficient calculation method is applied using Microsoft Excel tables. The summary should include the following information:
- load name;
- voltage power;
- number of loads;
- an indicator of the power that is used;
- demand ratio;
- cos value
After entering all the data, the system will automatically recalculate the calculated electricity and calculated power.
Simple rules that are recommended to be followed when filling out the table:
- You need to enter a list of loads present at the facility or devices that are planned to be installed. The compilation of the table depends on the careful selection and indicators of the data that are entered in the table.
- The principle of creating a table is not complicated - all loads of a dwelling should be collected in groups, electrical power is calculated for each group separately. With this method, the power will be easier to distribute across the phases.
- All indicators for calculating the table must be taken from the passport data of the units.
- It is important to consider the difference between current distribution in single-phase and 3-phase loads. A single-phase load accordingly loads one phase, in a 3-phase load the currents are distributed evenly over the three phases. The exceptions are capacity utilization and demand.
The calculation of single-phase and three-phase voltages is made according to different formulas.
Formula for single phase load: I = W * 1000 / U / N, where I is the load current A.
W - power indicator of the electrical appliance kW.
U - phase voltage 220 V.
N is the number of devices included in the group.
Formula for 3-phase load: I = W * 1000 / (U * 1.74), where I is the load current A.
W is the power of the electronic unit, kW.
U - line voltage 380 V.
Table for calculating the required wire section depending on the load
Cable section, mm 2
Table of power, current and cross-section of cable and conductor materials
Conductor cross-section, mm
Voltage, 220 V
Voltage, 380 V
|current, A||power, kWt||current, A||power, kWt|
The process of dividing electrical wiring into blocks will allow the distribution of energy while ensuring safe operation. It is necessary to calculate the current load for a set of outlets and lighting, if necessary, divide the unit by 2 or more. In connection with the division of electrical wiring into groups, you will need a large electrical panel for 24 or 36 calculation modules. Additionally, use the wire cross-section calculator.