Installation of temporary power supply networks for water supply lighting estimates. Construction site power supply
Most species construction work requires electricity. This applies not only to power tools, but also to lighting of workplaces, including in a construction trailer for workers in a temporary camp. Thus, it turns out that without preliminary electrical installation work and laying electrical wiring, it makes no sense to begin construction of objects. Major electrical work at the start of construction runs the risk of requiring significant changes as the work progresses. Therefore, the most optimal option is a temporary power supply to the construction site for the construction period, but taking into account the electrical design in accordance with current electrical safety requirements and other regulatory documents, including PUE and SNIP.
How to supply electricity to the site of proposed work or construction site?
Before starting design in design organization A technical specification is issued in which you must provide:
- composition and power of loads;
- category of connected consumers;
- power source - overhead or cable lines, transformer substation or autonomous source;
- consumer placement plan and lighting fixtures layout.
Based terms of reference and local conditions, the design organization considers options for connecting electricity, receives technical instructions (TU) from the electricity supply company, makes the necessary adjustments and proposals, which may relate to the construction of the necessary temporary mobile substations, laying overhead and cable power supply lines, taking into account the uninterrupted supply of electricity. Then a preliminary is performed.
After all the nuances have been agreed upon, a preliminary design and temporary diagram are created, and then the design is carried out in full, a single-line power supply diagram, a wiring plan are drawn up, and all necessary approvals are carried out. As in the design of power supply for residential and industrial construction projects, working and then as-built documentation is drawn up, which includes all changes made during the construction of temporary power supply devices and equipment.
Only after all of the above steps have been completed can construction begin in order to connect electricity to the construction site facilities.
It is most rational to design a temporary power supply taking into account the purpose of the work and construction. With this approach, the cost estimate for power supply to the constructed facility is significantly simplified.
Requirements and features of temporary power supply to construction sites
There are some subtleties in the design and construction of temporary power supply:
- the electrical system must be flexible with the ability to quickly redistribute, temporarily connect and connect loads in accordance with the current stages of construction;
- minimal costs;
- Working, emergency and security lighting for construction sites must be present;
- ensuring increased reliability and safety;
- it is required to lay temporary cable power supply lines on supports or suspensions;
- connecting the equipment and turning it on must be carried out only by switching equipment with a dust and moisture protection class IP of at least 54 - 65.
Consumers of the construction site of a residential building or other objects are mainly the following:
- welders;
- asynchronous motors of mechanisms and machines;
- equipment for heating concrete in cold weather.
Consequently, the need to include reactive power compensators in the project cannot be ruled out.
Who can carry out the design
Like the power supply project for a construction site, the calculation and preparation of a temporary power supply project for a construction site must be entrusted to an organization that has the right to carry out the design. Thus, you can get a guarantee of safety, completeness of the developed project, well-organized electricity metering and save yourself from a lot of hassle in coordinating the project and approving technical documentation and accepting the work performed.
The company "Mega.ru" is engaged in the development of all stages of design in Moscow and the Moscow region. The company's specialists also provide assistance in areas adjacent to the Moscow region. At some stages and for certain types of work, remote cooperation throughout the territory is provided Russian Federation. All prices for work, as well as other necessary information, can be clarified using the coordinates located on the page.
And samples and standard projects You will find other objects in the corresponding articles on our website.
Requirements:
1. Providing energy in the required quantity of the required quality;
2. Flexibility electrical network;
3. Reliability of the electrical network;
4. Minimizing energy supply costs.
Design order:
1. Calculate electrical loads;
2. Selecting a source of electricity. Determination of the number and capacity of transformer substations;
3. Identification of an object of the first category requiring backup power supply;
4. Transformer substations, power and lighting networks, and inventory electrical devices are placed on the SGP.
Purpose of the network - permanent and temporary power supply networks are designed to supply energy to power and technological consumers.
The initial data for organizing temporary energy supply are the volumes, timing and structure of construction and installation work, the area of temporary buildings, structures and closed warehouses, the size of the construction site, the types and capacities of construction machines, etc.
Design of temporary power supply is carried out in the following order:
Determine electricity consumers, the amount of required electrical power per shift for each consumer and the total required power of electrical installations or transformers;
The appropriate type of transformer is selected, its location is established on the general plan and a temporary power network is designed.
a is the coefficient of power loss in the network;
Рс – capacity of power consumers;
Рт - capacities for technical needs;
Рсв - power consumption for welding transformers;
Ditch - power consumption of lighting fixtures for interior lighting;
Ron - power consumption for outdoor lighting;
cosj1 =0.7 - power factor for motors;
cosj2 =0.8 - power factor for technical purposes;
K - coefficients of simultaneous energy consumption:
K1=0.4; K2=0.4; K3=0.8; K4=0.9; K5=0.8.
1. Total power of motors for construction machines and mechanisms (SРс):
Tower crane BK 404M - 1 piece - 71 kW,
Lift S-867 – 2 pieces – 24 kW,
Painting unit - 1 piece - 4 kW,
Various small mechanisms and tools – 5.5 kW
SPc = 104.5 kW
2. Total power of welding transformers (SPsv):
TS-500 Рс = 32 * 2 = 64 kW,
3. Power for indoor lighting (SPov):
closed warehouses
2 W/m2 * 40 m2 = 80 W = 0.08 kW
repair shop
15 * 25.23 = 378.45 W = 0.378 kW
offices and office premises
15 * 48 = 0.72 kW
SPov = 1.178 kW
4.Power for outdoor lighting (SPron):
main passages and passages
210 * 5 = 1050W = 1.05kW
secondary passages and passages
210 * 2.5 = 525W = 0.525kW
security lighting
2 * (70 + 30) * 1.5 = 300W = 0.3kW
open warehouses
7 * 50 * 2 = 700W = 0.7kW
lighting installation
760.3 * 3 = 2281W = 2.281kW
SPron = 4.856 kW
5. Technological needs for an electric heater with a power of RT = 500 kVA
We choose a transformer substation - SKTP-560 1 pc.
With Р=560kVA.
Local estimate for civil works
Local estimate for special work
Local estimate for improvement
Object estimate
Technical and economic indicators
1. Building volume - 37483 m3
2. Building area - 13154.4 m2
3. Total labor costs for all work - 23,828 people - days
4. Total estimated cost of construction - 82,964,090 rub.
5. Estimated cost per unit area of the building – 13.983 RUR/m2
6. Estimated cost per unit volume of the building - 2213 RUR/m3
7. Average output per worker per day
· On general construction works - 3687 RUR/person-days
· On special jobs - 1792 RUR/person-days
· Overall for the facility - 3482 RUR/person-days
8. The standard duration of construction according to SNiP is Tn = 360 days.
9. The actual duration of construction is T f = 352 days.
10. Construction duration indicator -
PPP = T f / T n = 352 / 360 = 0,98
List of references for the section:
1. SNiP 1.04.03.85 “Norms for construction duration and backlog in the construction of enterprises, buildings and structures.”
2. SNiP IV-2-82 “Collections of elemental estimate standards for building structures and work.”
3. Teplichenko V.I., Terentyev O.M., Lapidus A.A. "Technology construction production, coursework and diploma design.”
4. ENiP 4-1-1 “Installation of prefabricated and installation of monolithic reinforced concrete structures.”
5. Teplichenko V.I., Terentyev O.M., Lapidus A.A. “Technology of construction processes.”
The figure shows an example of temporary power supply to a large construction site.
Input of three-phase voltage 3 x 380V, 50Hz to the construction site is carried out through three channels INPUT No. 1, INPUT No. 2 and INPUT No. 3. Consumption from the supply network by each of the six inputs of these channels is no more than 400 A. In each of these channels, input is carried out using two NKU SP input and measurement. The first, NKU SP-VI-400-1-19.01, drawing TPEP.656443.001-19.01 forms Input 1.1, Input 2.1 and Input 3.1, respectively. Second, NKU SP-VI-400-2-20.00, drawing TPEP.656443. 001-20.00 forms, respectively, Input 1.2, Input 1.3, Input 2.2, Input 2.3, Input 3.2, Input 3.3.
These SP input and measurement NKUs are connected to SP NKUs, which distribute electricity throughout the construction site.
To Input 1.1, similarly to Input 2.1 and Input 3.1, the main distribution NKU SP with one output block NKU SP-GRP-250-1-04.00, drawing TPEP.656443,002-04.00, is connected. The tower crane of the construction site is connected to the output block of this NKU SP through the main distribution NKU SP-GRP-250-1-04.01, drawing TPEP.656443.002-04.01, which is permanently installed next to it.
To Input 1.2, similarly to Input 2.2 and Input 3.2, an SP distribution NKU with five output blocks NKU SP-RP-250-5-01.05, drawing TPEP.656443.003-01.05, is connected. The terminal distribution NKU SP-K-63-1-01.02, drawing TPEP.656443.004-01.02, is connected to the first output block of this NKU SP through an extension cord, which provides power to the internal lighting circuits. The NKU SP terminal distribution NKU SP-K-100-2-04.05, drawing TPEP.656443.004-04.05, is connected to the second output block through an extension cord, which provides power to the welding transformer and, through the extension cord and NKU SP, plug-in power to the power tool. These terminal NKU SP can independently move to various technological points of the construction site. The third and fourth blocks are water - reserve. A power tool is connected to the fifth output block via an extension cord and a portable NKU SP plug.
To Input 1.3, similarly to Input 2.3 and Input 3.3, the main distribution NKU SP is connected with two output blocks NKU SP-GRP-100-2-01.01, drawing TPEP.656443.002-01.01, to the first output block of which the change house is connected through a permanently installed NKU SP main distribution NKU SP-GRP-100-1-00.04, drawing TPEP.656443.002-00.04. The external lighting network of the construction site is connected to the second output block through the permanently installed NKU SP main distribution NKU SP-GRP-100-1-00.05, drawing TPEP.656443.002-00.05.
In this scheme, the power supply for the internal lighting circuits and power tools is carried out using differential circuit breakers with a residual current device.
The supply network is made of four wires, A, B, C+PEN. In channels Input 1.1, Input 2.1 and Input 3.1 this four-wire network extends to the control circuit of the tower crane. In the remaining channels, this network is converted into a five-wire network, A,B,C.N,PE.
When starting to build a house, you definitely need to worry about the electrification of the construction site, since there is practically nothing to do on a modern construction site without the help of power tools. Concrete mixers, jackhammers, hammer drills, cutting machines, drills, welding machines are powered by electricity and greatly facilitate and speed up the construction stages, so temporary power supply to a construction site is the first stage of any construction project.
Electrical network requirements
First of all, we provide the requirements for temporary power supply to the site where construction work is being carried out:
- Reliability. Uninterrupted supply of electricity for the construction period.
- Quality. The frequency and voltage must guarantee the operation of electrical devices.
- Safety. Maximum protection for personnel and operators on the construction site.
To do this, it is necessary to document organizational issues related to connection to existing highways of sufficient capacity
Organizational events
Depending on the location of the site where construction is taking place, a method for supplying temporary power supply is selected. The choice of cable routing type is influenced by the following points:
- Distance from power lines.
- Type of object: residential building, warehouse or production workshop.
- Estimated power consumption.
- Choice of network: single-phase or three-phase.
- State of the nearest overhead line power transmission
Based on these options, select The best way installation of temporary power supply at the construction site. This may be a connection to existing networks or installation of an autonomous power generator. When connecting to the power grid, it is better to individually clarify the calculation procedure and other conditions with the power grid and energy sales organization.
Features of connection to existing electrical networks
The first situation we will consider is that construction is taking place in close proximity to your own home. The method of electrification from an already registered input is considered less expensive and more preferable. During construction work, electricity that is already present at the site is consumed and payment for it occurs in accordance with a previously concluded agreement. This option is suitable for temporary power supply to a private home.
After the construction of a new facility and, possibly, dismantling of old buildings, there will be a need to re-register the contract with the supplying organization.
To do this you need:
- Indicate the estimated power consumption.
- The organization also has a connection point for input.
- Order project documentation.
- The project must be coordinated with the State Technical Supervision Authority.
- Perform electrical installation work.
- Call an electrical laboratory to evaluate and draw up a test report.
- Conclude an agreement with the energy supply company and commission the facility.
All documents are provided in the photo:
Please note that in order to make temporary electrical wiring, you will also need to complete this package of documents.
In cases where the construction site is located 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 power grid organization and write an application for a technological connection, after which you should be given technical specifications. After completing the documents, you must comply with the terms of the technical specifications and contact the network organization again to connect the switchboard and seal the metering devices. More details about the connection are described in the video:
Commissioning at the facility must be done as for permanent operation. To do this, you need to install an external vandal-proof shield with protection class IP54. The box is installed in such dimensions that it is possible to install a meter and protection devices, sockets and grounding bars. It is also necessary to provide space for backup power supply.
When building within a non-profit partnership, the cost of services for collective connections is much cheaper for country, gardening and garage cooperatives. They have a transformer substation to which it is possible to connect. Many teams have already established themselves and formed. Repairs and modernization of equipment were carried out at their expense, transformers, and installation of overhead lines. Newly emerging developers may be presented with monetary compensation for work already carried out and modernization of some equipment.
Another situation that I would like to consider is temporary power supply to a private house from neighbors. If, due to reasons beyond your control, electrification is being adjusted, but deadlines are running out, then it’s worth reaching an agreement with your neighbors. If such a kind person found, through an additional metering device the power supply is connected for the period of repair and construction. The amount of power supplied is specified in advance (control by metering device) and the installation of a protective limiting device. This is the easiest way to make temporary wiring to the site.
Separately, it is necessary to consider such a method of supplying electricity as. From a technical point of view, generator sets provide high-quality electricity. Builders use them at their own discretion and do not depend on anyone. The disadvantage is the high cost of the electricity produced. This type of supply is mainly resorted to at the beginning of construction, when there is a hitch with temporary supplies at the stage of paperwork.
Technical events
After all organizational issues have been resolved and a temporary power supply scheme has been selected at the construction site, the location for installing the input panel on a rack or support is determined. An additional support is also installed if the site is more than 25 meters away from the power line (see, clause 2.4.12.). But this value may differ even less according to the PUE Chapter 2.4. clause 2.4.19. According to the rules, the input panel is installed on the border or territory of the applicant. From the input box, cable routes or power transmission poles are already marked to the work site, power and lighting networks. For optimal distribution of power throughout the construction site, power wires are connected to lifting mechanisms, to the concrete preparation site, woodworking site, and the place where welding work is performed.
At the beginning of construction, a temporary lighting system may consist of several spotlights, and will be divided into main and emergency, local or general. You can learn more about it in our separate article.
Consumer connection diagrams
During the construction of the building, cable laying routes appear, the type and length of the cable, the characteristics of the loads are indicated, and a diagram for their inclusion is created. The connection diagram can be radial, ring, mixed wiring. Radial power is produced from one input, from which cables are distributed to power posts and lighting installations. If the developer has a backup generator, the temporary power supply scheme will be a ring or mixed type. The radial circuit is duplicated by the connection circuit from the generator set. This type supply allows construction to continue in the event of possible power failures.
Input design
One of our articles already talked about independent personal plot. The technology for assembling this shield is not much different; let us recall the important points.
The metering device and protection devices, such as, must be located in a sealed box that prevents the entry of moisture and foreign objects. It is also necessary to organize a grounding device, ground the shield and re-ground the zero from the overhead power line (clause 1.7.61), organize a system (PUE chapter 7.1, clause 7.1.13). Do not forget to take all safety measures to carry out the work.
Cable laying is possible both in trenches, in places where it will not experience loads from vehicles passing over it, or by hanging it on a cable at a safe height. We recommend studying the technology at your dacha.
Security measures
Construction always means movement and movement, which can result in unforeseen risks. 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. Related workers with a low tolerance group, or without qualifications, presence of flammable and caustic materials at the construction site, 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 require protection from indirect contact in cases where the voltage exceeds 50 Volts AC and 120 Volts 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 connects all open housings using protective connectors in the socket.
When illuminating an object, luminaires are chosen with IP54 protection class for outdoor installation. By following our recommendations and current rules, you will reduce the risk of injury to a minimum. Take care of yourself. Finally, we recommend watching a video that demonstrates a panel for temporarily supplying an area with electricity:
That's all I wanted to tell you about what temporary power supply to a construction site is and what requirements are placed on it. We hope you found these basics useful and interesting!