How to choose a section of wires for sockets: conductor calculation

When designing a major overhaul, you need to know exactly what section of the wire is needed for outlets in the apartment. The comfort and safety of living in the house depend on the correctness of the decision made and its practical implementation. A wide selection of electric cables of various classes and purposes is on sale. Products have certain characteristics that determine the scope of their application. When choosing a product, several factors must be taken into account, among which quality comes first.

Which conductor to use for arranging electrical wiring in an apartment

In most houses built in the mid-to-late last century, the entrance groups and internal communications were made of aluminum. This metal was preferred because of its low cost, which was crucial in the context of mass construction on a national scale. Subsequently, this decision played its evil role, due to the numerous shortcomings of aluminum.

The most unpleasant properties of metal:

1. Brittleness. The veins break after 2-3 bends. This phenomenon has to be encountered in the process of frequent replacement of switches and sockets.
   

   Most of the aluminum wires break, it is worth bending them several times
2. Low conductivity. Because of this, the line often heats up and the insulation melts. The occurrence of fires for this reason is not uncommon.
3. Oxidation. Over time, a film with dielectric properties appears on the metal surface. Because of this connection in the contacts and twists lose their conductivity. Over time, contact may disappear altogether.

Plus, aluminum is flexible and pliable. The wire can be shaped into any shape, which is convenient for installation.

In accordance with changes in GOST, since 2001, the use of aluminum in residential construction is prohibited. Priority is given to a copper cable with a grounding conductor. The price of such products is several times higher than that of aluminum, but the investments are justified by the high performance characteristics of the metal.

Advantages of copper:

1. Elasticity. Wires can be bent and twisted up to 100 times before they break.
2. Durability. Copper does not change its characteristics throughout the entire period of operation of the building, which is 50-100 years.
3. Excellent electrical conductivity. Due to this, a smaller conductor can be used, which positively affects the price of products.
4. Flexibility. This quality helps to pull cables through narrow channels without resorting to wall chipping.

In addition to the high cost, the metal has one drawback - it is oxidized and covered with a patina, which conducts electricity poorly. You can prevent the occurrence of this phenomenon in advance by soldering the contacts with tin.

Thus, when choosing a cable for outlets in the apartment, you need to stop your choice on products with copper conductors.

What type and brand of conductor to choose for the outlet

When choosing a cable for outlets, it is necessary to take into account their number in each room and the power of the packet switch at the entrance. In all cases, it is necessary to focus on the maximum load that will be provided at each point. In addition, you must remember about the safety factor.This is the material of which the cable insulation is made. Depending on the model, it can release substances of varying degrees of toxicity when heated. This topic is especially relevant for bedrooms and children's rooms.

For the equipment of premises, products of the following brands can be used:

1. VVG - double insulation of polyvinyl chloride. Flammable plastic, flammable, does not fade on its own. Recommended for use in fire-safe rooms.
2. VVGNG - insulation with double protection, the basis of which is non-combustible PVC, capable of self-extinguishing after exposure to an open flame. It can be used both in brick and wooden houses.
3. VVGNG-LS - wires with double protection from halogen-free polyvinyl chloride, which does not emit smoke when heated and in contact with fire. It is allowed to install in medical and preschool institutions.
   
4. NYM- (N). A German-made product that is of high quality and combines all the advantages of domestic-made products. When ignited, the insulation does not burn, does not smoke, maintaining integrity and tightness. It is used without restrictions, including in rooms where explosive substances are stored.

In accordance with the requirements of SNiP, for internal wiring to outlets in the apartment, it is recommended to use copper wires with a cross section of 2.5 mm². The rated power of such a product is 6 kW with a current strength of up to 28 A. When using sockets with appropriate indicators, almost all household appliances and appliances available on the network can be connected. To avoid overloading the line and individual points, you should install an automatic machine with a capacity of up to 25 A.

When choosing the wire cross section for outlets, we must not forget about the number of cores in the cable. Regardless of the type of entrance to the apartment, you should choose products that have grounding. If a grounding line is installed in the house, then you do not have to change the wiring to connect to the new core.

Future load calculation

To determine which cross-section wires are needed for outlets, you need to calculate the load that they will take with the maximum number of connected consumers.

The following data are taken into account (in watts):

• air conditioning - 1000;
• water heater - 1200-1500;
• dishwasher - 1000;
• oven - 1200;
• iron - 1800;
• electric kettle - 2200;
• automatic washing machine - 1500;
• vacuum cleaner - 1400-1700;
• computer - 500;
• rotary hammer - 1300;
  
• grinding machine - 800;
• hair dryer for hair - 1000;
• fireplace - 2000;
• instantaneous water heater - 5000.

Other devices, including lighting, can be neglected, since they do not significantly affect the level of load.

Peak consumption is observed in summer and winter, when heaters, air conditioners and washing equipment are operating at the same time. The total load on one outlet can be up to 4.5 kW, and on the apartment as a whole - up to 12-15 kW. Based on this, you need to select the cross section and type of wires.

Power conductor calculation

When planning the arrangement of an apartment and a house, it is not at all necessary to equip the property with expensive cables with the maximum allowable power. Given the cost of quality products - this is an unnecessary and unnecessary waste of money. It should be guided by the principle of reasonable sufficiency, leaving a sufficient margin of reliability.

It is recommended to use such models to connect consumer groups by capacity:

• VVG 3 × 2.5 mm² - for consumers with power up to 2200 W: small household appliances, washing and dishwashers, air conditioners and boilers, hand-held building tools;
• VVG 5 × 2.5 mm² - for consumers of high power over 2000 W: instantaneous water heaters, ovens, heat guns, welding machines, electric motors;
• VVG 2-3 × 1.5 mm² - for small household appliances and tools: floor fans, floor lamps, sconces, perforators, overhead and side light.

When choosing wiring, you need to remember that a good thin cable can easily withstand short-term increased load of up to 30 minutes. This allows you to connect powerful consumers (vacuum cleaner, tools, compressors) to outlets with 1.5 mm² cores.

Calculation of the cross section

Cross-section of the input cable to the apartment

When calculating the core diameter of the input cable, it is necessary to mathematically calculate how many consumers can be connected to the line at the same time and their total power. If we take the ability of a copper wire to pass 2.4 kW per 1 mm² without losing its characteristics, it is easy to obtain the desired result. If the maximum design consumption is 12 kW, the minimum permissible cross-section is 5 mm². For peak loads, it is better to increase it slightly and stop at 6 mm². Then you need to separate the cables from the meter into the rooms. The calculation is carried out similarly. The recommended parameter is 4 mm² to the mounting boxes. Such wires are guaranteed to withstand up to 12 kW of load on one separate room.

Cable section for outlets

The safety of housing operation and the convenience of living in it depend on the correct choice of the wire section for outlets. Standard household sockets are designed for a maximum cross section of 2.5 mm of wires connected to them. This option is due to the restrictions that are inherent in the house line. She simply can not stand it if all consumers simultaneously use 10-15 kW in each apartment. Exceeding the permissible load will lead to burning out of the contacts, melting of the insulation or failure of the common transformer.

For the kitchen and bathroom, you need to choose wires with a cross section of 2.5 mm, since these rooms contain the most powerful consumers. For the living room, the nursery and the bedroom there is enough line with veins of 1.5-2 mm. This is enough to connect fireplaces, air conditioners and other household appliances.

Wire cross section for lighting

The choice of material for arranging lighting systems is based on the types of lamps that will be used for this. If it will be halogen or spiral products, it is worth taking care of sufficient wiring power. But even if a lamp with 10 horns of 100 W each is installed, the total power of the structure will not exceed 1 kW.

Today, few people use incandescent lamps, switching to LED crystals, which, with the same brightness, consume 6-10 times less energy. Based on this, a cable with wires of 0.5-1 mm is sufficient for mounting the lighting system. All that is thicker will be reinsurance and an unnecessary waste of money.

Single or multi-wire cable selection

A monolithic core has rigidity and brittleness during repeated bending. The cable is difficult to pull in curved channels, as it bends badly, and after that it no longer straightens. However, a one-piece wire retains conductivity and cross-sectional area throughout its entire period of operation, which can be up to 100 years.

Stranded wire is easier to work with. It is flexible, durable and resilient; it is easily dragged into the most complex cavities. The downside is that the cross section of the threads is gradually reduced due to the oxidation of their walls. Over time, the patina can take up to 50% of the material, which will lead to a decrease in power and throughput of the line.

How to distinguish high-quality cable from low-quality

In construction stores a wide range of electrical cushioning products is presented. It’s difficult to understand, but possible.

You can distinguish a high-quality cable from a low-quality cable by the following signs:

1. The presence of a certificate. For the original product there are accompanying papers with information about the manufacturer and a copy of the quality certificate.
2. Compliance with technical requirements. If the product has a GOST mark, it complies with international standards.TU - these are local standards that can be very far from accepted in the country.
3. Color and degree of stiffness of the core. High-quality electrical copper has a uniform color and bends well. The counterfeit is heterogeneous and fragile.
4. Section size. It is checked by mechanical or electronic devices.
5. Isolation condition. It should be smooth, dense and without mechanical damage, easily detachable from the metal.
6. Reaction to the fire. Quality insulation darkens, hardens and cracks. At a fake, it melts, stretches, burns and smokes.

Lastly, pay attention to the cable marking. It should be printed in a clear and even font indicating the brand, name of the manufacturer, designation of the standard and year of manufacture.