How to organize temporary power supply at a construction site?

Power Requirements

First of all, we provide requirements for temporary power supply to the site on which construction work is carried out:

1. Reliability. Uninterrupted supply of electricity for the construction period.
2. Quality. Frequency and voltage should guarantee the operation of electrical devices.
3. Safety. Maximum protection of personnel and operators at the construction site.

For this, it is necessary to document organizational issues associated with connecting to existing highways of sufficient capacity

Organizational activities

Depending on the location of the site on which construction takes place, a method is selected for the supply of temporary power supply. The following points affect the choice of cable routing:

• Remoteness from the power line.
• Type of object: residential building, storage facilities or production workshop.
• Estimated power consumption.
• Network selection: single-phase or three-phase.
• The status of the nearest overhead power line.

Based on these options, the best way to install temporary power supply at the construction site is selected. This can be a connection to existing networks or the installation of an autonomous generator. When connected to the power grid, it is better to individually determine the calculation procedure and other conditions at the power grid and the power supply organization.

Features of connecting to existing power grids

The first situation that we will consider is construction being carried out in the immediate vicinity of our own housing. The electrification method from an already registered input is considered less costly and more preferable. For the duration of the construction work, electricity is consumed, which is already present at the facility and payment for it occurs according to a previously concluded agreement. This option is suitable for temporary power supply of a private house.

After the construction of a new facility and, possibly, the dismantling of old buildings, it will be necessary to renew the contract with the supplying organization.

To do this, you need:

1. Indicate the estimated power consumption.
2. The organization get technical specifications and a connection point for input.
3. Order design documentation.
4. Coordinate the project with state technical supervision.
5. Perform electrical work.
6. Call an electric laboratory to evaluate and draw up a test report.
7. Conclude an agreement with energy sales, commission the facility.

All documents are presented in the photo:

Please note that in order to make temporary wiring, you also need to draw up this package of documents.

In cases where the construction site is far from power lines, the construction of a new overhead line (or cable laying) will be required. To do this, you need to contact the electric grid organization and write an application for a technological connection, after which you should be given the technical specifications. After completing the documents, you must comply with the TU conditions and will again contact the network organization to connect the shield to pipe rack and sealing metering devices. More about connection is described in the video:

Input at the facility must be done, as for continuous operation. To do this, install the external vandal-proof shield with protection class IP54. The box is installed in such dimensions that it is possible to install a meter and protective devices, sockets and grounding buses. You also need to provide a place for backup power supply.

When building within a non-profit partnership, the cost of services for collective connections is much cheaper than cottage, gardening and garage cooperatives. They have a transformer substation to which they can connect. Many groups have already settled and formed. Repair and modernization of equipment was carried out at their expense, installation of supports, transformers, laying of overhead lines. Newly appearing developers may be presented with monetary compensation from the work already done and the modernization of part of the equipment.

Another situation that I would like to consider is the temporary power supply of a private house from neighbors. If the electrification is debugged from reasons beyond your control, and the deadlines are running out, then you should agree with the neighbors. If such a kind person is found, through an additional meter, the power supply is connected for the period of repair and construction. The amount of power supplied (control by metering device) and the installation of a protective limiting device are agreed in advance. In this way, it is easiest to make temporary wiring to the site.

By the way, I would like to step back a little from the topic and invite you to get acquainted with the methods of temporary power supply of the apartment. Find out what you can do if turned off the light in the apartment for non-payment.

Separately, you need to consider such a method of supplying electricity as electric generator connection. From a technical point of view, generating sets provide high-quality electricity. Builders use them at their discretion and are not dependent on anyone. The disadvantage is the high cost of electricity generated. This type of supply is mainly resorted to at the beginning of construction, when a temporary hitch occurred at the stage of paperwork.

Technical Activities

After solving all organizational issues and choosing a temporary power supply scheme at the construction site, determine the place for installing the input panel on a rack or support. An additional support is also installed if the site is removed from the power line by more than 25 meters (see chapter 2.4. PUE, clause 2.4.12.). But this value may differ to a lesser extent according to the PUE chapter 2.4. Section 2.4.19. According to the rules, an input shield is installed on the border or territory of the applicant. From the input box, marking of cable routes or power poles to the place of work, power and lighting networks is already being made.For optimal distribution of power over the construction site, the power wires lead to the lifting mechanisms, to the concrete preparation site, the woodworking site, the place of welding.

At the beginning of construction, the temporary lighting system may consist of several spotlights, and will be divided into main and emergency, local or general. Learn more about types of lighting You can in our separate article.

Consumer Connection Schemes

During the period of construction of the building, cable laying routes appear, the type and length of the cable, the characteristic of the loads are indicated, a scheme for their inclusion is created. The connection diagram can be radial, ring, mixed wiring. Radial power is produced from a single input, from it are distributed by cables to power posts and lighting installations. If the developer has a backup generator, then the temporary power supply scheme will be ring or mixed type. The radial circuit is duplicated by the connection circuit from the generator set. This type of supply allows you to continue building in case of possible power outages.

Input design

One of our articles has already talked about self three-phase shield assembly on the plot. The assembly technology of this shield is not much different, we recall important points.

Metering device and protection devices, such as circuit breaker, RCD must be in a sealed box, preventing the ingress of moisture and foreign objects. It is also necessary to organize a grounding device, ground the shield and make a repeated grounding of zero from the high-voltage line (PUE chapter 1.7. Section 1.7.61.), organize the system TN-C-S (PUE chapter 7.1. P. 7.1.13). Do not forget to take all safety measures for the performance of work.

Cable laying is possible both in trenches, in places where it will not experience stress from vehicles passing through it, or by suspension on a cable at a safe height. We recommend to study technology installation of cable wiring in the country.

Security measures

Construction is always movement and movement, as a result of which unforeseen risks may arise. Therefore, special requirements are imposed on temporary power supply, since there is such a factor as the adverse effect of the atmosphere on the elements of electrical installations and their parts. Adjacent workers with a low tolerance group, or without qualifications, the presence of combustible and corrosive materials at a construction site, the lack of grounding and potential equalization elements for electrical appliances.

When working in conditions of high humidity, you must follow the current rules of PUE 1.7.50-53, which prescribe the protection RCD installation, with indirect contact in cases where the voltage exceeds 50 Volts AC and 120 DC. Also, to increase the safety of personnel working with power tools, it is necessary to use isolation transformers with a potential equalization system that combines all open housings with protective connectors in the socket.

When illuminating an object, fixtures are selected with IP54 protection class for installation in the open air. Following our recommendations and current rules PUE You minimize personal injury risks. Take care of yourself. Finally, we recommend watching a video in which a shield is shown to temporarily supply electricity to the site:

That's all I wanted to tell you about what constitutes temporary power supply to the construction site and what requirements are presented to it. We hope these basics were useful and interesting for you!

It will be interesting to read:

• How to pass light from a pillar to a house
• DIY wiring in a new building
• How to make an estimate for electrical work