After a decision was made about the construction of the cottage, a project was made and all permits were obtained, it is possible to start construction. But, before importing building materials and to start land work, the power supply of the construction site should be ensured.

Electrical Synopation Requirements

Electricity consumers at the construction site are:

• single and three-phase engines of electrical machines and mechanisms;
• welding devices;
• heaters;
• installation of technological warming of concrete;
• lightning equipment.

The power supply of the construction site must be completed in such a way that it was provided:

• power supply reliability;
• safety of builders and utility staff during operation;
• efficiency.

Temporary electricity supply of the construction site is mounted in compliance with the safety rules.

1. To protect builders from electric shock in case of damage to isolation, a protective ground must be provided. The corresponding contact terminals on the electrical machines (lifting mechanisms, concrete mixers, etc.) are connected to the grounding circuit.
2. Protective shutdown devices (UZO) are installed: they turn off the power supply in the event of a leakage current.
3. Specially designed for operation in these conditions cables with properly selected sections lived.
4. Operation of portable extension cords in the intended state is not allowed.
5. It is necessary to hang cables for supports, not allowing their gasket on the ground.
6. It is allowed to use sockets and forks with a level of protection against moisture not lower IP54.
7. To install circuit breakers, the RCD and switching, the closed metal box on the support should be provided. The box must be grounded.

Project of temporary power supply of the construction site

Before proceeding to the design of the power supply of the construction object, the conditions of connection and operation are studying. At the same time take into account:

• remoteness of the object from the power grid;
• appointment of construction object (cottage or cottage);
• method of connecting the construction site (on an ongoing basis or temporary);
• the required power of the network (based on the total consuming power of the equipment);
• required number of phases (220 or 380 V);
• in what condition are the sources of power supply of the construction site (the need for the need for reconstruction is found);
• dates.

It should be borne in mind that the power supply of the construction site can be provided from a stationary source or from temporary. Stationary sources include transformer substations, air power transmission lines and ground distribution devices, to temporary - diesel (gasoline) generators.

The video shows the operation of diesel generators at the construction site.

Choosing sources of power supply

Stationary sources that are objects of district power grids, more preferred. But in the event that the connection is performed directly to the LEP (except 0.4 kV lines), a lowering voltage transformer is used. At the same time, the power of the transformer must correspond to the total power of consumers (plus 15% reserve).

Complete transformer substations (KTP) are mobile, open and closed. It is closer to the center of connecting all consumers closer to the construction site, but outside the zone of the lifting mechanisms.

Planning power grids at construction site

Installation of the power supply on the construction site is performed using cable underground and air lines. In the event that underground lines cannot be further used on an ongoing basis, it is recommended to use power lines. Cable underground lines are used when the operation of air power transmission lines can be dangerous.

When planning power grids are guided by the following rules.

1. For the construction of the construction site usually use a four-wire voltage of 380 V. The equipment is connected to it, for which three phases are required, as well as single-phase consumers (for which the "zero" wire and one of the phases use).
2. Lighting is connected to a separate network that is not associated with the power of high power electrical equipment.
3. The time of the temporary airline should be as direct as possible.
4. For lighting lines and for installation of power lines, the use of common temporary supports is allowed.
5. The depth of the trench for laying cables is not less than 0.8 m. At the bottom of the trench, there should be a padding from sand or sifted soil. Under the roadway, the cables are protected by concrete floors or near bricks.
6. The cable length should be sufficient for laying a slightly wavy line to compensate for the soil movement.
7. The minimum allowable distance from the power underground cables to other communications is 0.5 m. At the same time, in places of the largest rapprochement, the cables are protected by a metal sheath or packed in steel pipes.
8. To account for the expendable electricity, the timeline must be connected to the meter.

Select cables

1. The cross section and material of the cores are chosen according to the maximum allowable current exceeding the calculated value by 10-15%.
2. For laying in trenches, armored cables are used.
3. To connect to the electrical network of special equipment, which is necessary at the construction site, use portable (hose) cables with PVC or rubber insulation.
4. Internal illumination networks are mounted using copper wires with a cross section of 2.5 mm² or aluminum - 4 mm².
5. The mechanical strength of the air line can be provided by aluminum wire cross-section of the vein from 16 mm² and more or steel aluminum - from 10 mm².

To ensure the power supply of the construction site, the project of electrical networks is based on the plan for the landscaping of the preservation area. Air lines and underground cables should not interfere with land performance.

Options and Power Supply Schemes for the Construction site

Depending on the nature of the site where construction is planned, various schemes for connecting a temporary power supply to the source can be involved.
In the event that there are no buildings and neighbors on the site, from which it would be possible to temporarily lay the wiring for construction, operate in the following order.

1. Calculate the planned load and find out the required power. It is important to "meet" at 15 kW: In this case, the connection can cost cheaper (there is a preferential rate at the length of the time line up to 0.5 km beyond the city and 300 m - in the city trait).
2. We make an application for connecting to the owner of the power grid, where we indicate the wishes (the required power, voltage, the level of reliability, etc.).
3. We get the technical conditions from the power supplying enterprise.
4. According to that, we order a project and coordinate it with a network organization.
5. We carry out the work provided by the project.
6. We carry out the testing of the power grid.

The use of a network of an old structure existing on the site is possible only for the period of construction. In this case, the quality of the wiring and the type of voltage must satisfy the needs. In the future, after entering a new home into operation, the connection must be performed according to the scheme provided by the project. In this regard, it is necessary to take care of the design of all permits and specifications. It is important to order an increase in power: in modern house the total power of consumers may exceed the previous power. Also should be changed (if necessary) the number of phases.

Similarly, the use of electrical buildings of neighborhoods (when coordinating with their owners) is performed. Calculations of the consumed electricity are performed based on the time of the installed additional meter.

In conclusion, the video material with the recommendations of a specialist about what to take into account when designing the power supply of the house.