We have talk a lot about names, materials, individual characteristics and even temperature, but we have lost sight of life circumstances.
So if you hire an electrician to install cross-sections for wiring in an apartment in the rooms of your apartment or house, the following values are usually accept. For lighting, the wire cross-section is taken as 1.5 mm 2, and for sockets, 2.5 mm 2.
If the wiring is intend for connecting boilers, heaters, stoves, then the cross-section of the wire (cable) is calculat individually.
Selecting the wire cross-section bas on the number of consumers
Another thing I want to say is that it is advertising data to use several independent power lines for each of the rooms in a room or apartment. This way you will not use a 10 mm2 wire for the entire apartment, running to all the rooms, from which branches go.
Such a wire will come to the input circuit breaker, and then from it, in accordance with the power of the consum load, the select wire cross-sections what makes up the price of a smartphone? be distribut for each of the rooms.
Typical basic wiring diagram for an apartment or house with an electric stove (indicating the cable cross-section for electrical appliances)
Current loads in DC networks
In networks with direct current, the cross-sections for wiring philippines numbers an apartment of the cross-section is somewhat different. The resistance of the conductor to direct voltage is much higher than to alternating voltage (with alternating current, resistance is generally neglect at lengths up to 100 m).
In addition, for direct current consumers, it is generally very important that the voltage at the ends is not lower than 0.5V (for alternating current consumers, as is known, voltage fluctuations within 10% in either direction are acceptable).
There is a formula that determines how much the voltage will drop at the ends compar to the base voltage, depending on the length of the conductor, its specific resistance and the current in the circuit:
U = ((pl) / S) I
Where:
- U — DC voltage, V
- p — specific resistance of the wire, Ohm*mm2/m
- l — wire length, m
- S — cross-sectional area, mm2
- I — current strength, A
Knowing the values of the specifi indicators, it is quite easy to calculate the cross-section you ne: by the substitution method, or using cross-sections for wiring in an apartment simplest arithmetic operations on the given equation.
If the drop in direct voltage at the ends is not important, then the table for alternating current can be us to select the cross-section, but in this case the current values should be adjust downwards by 15%, i.e. with direct current, the reference cross-sections of the cable can pass 15% less current than indicat in the table.
A similar rule also works for selecting circuit breakers for DC networks,
for example: for circuits with a load of 25A, you ne to take a circuit breaker with a rating that is 15% smaller, in our case, the previous circuit breaker size is suitable – 20A.
A cable transmitting electric current is one of the most important elements of an electrical network. If a cable fails, the operation of the entire system becomes impossible, therefore, to prevent failures, as well as the risk of fire from overheating, it is necessary to accurately calculate the cable cross-section according to the load.
This calculation provides confidence in the safe and reliable operation of the network and devices, but more importantly – the safety of people.
Selecting a cross-section that is insufficient for the current load leads to overheating, melting and damage to the insulation, which in turn leads to a short circuit and even a fire. So there are many reasons to make calculations and carefully select the right cable.
What is ne for load calculation
The main indicator that helps to accept cross-sections for wiring in an apartment the cross-section and brand of the cable is the maximum permissible long-term load (by current). In simpler terms, this is the amount of current that the cable is capable of passing under the conditions of its installation without overheating for a sufficiently long time.
To do this, a simple arithmetic summation of the power of all electrical appliances that will be connect to the network is requir.
The next important step to achieve safety is to calculate the cable cross-section according to the load, for which it is necessary to calculate the current strength using the formula: