Connecting a house, a transport facility or an engineering structure to a power supply system involves a series of electrical installation work. Their list and execution parameters depend on the conditions for the implementation of the task, but almost always we are talking about a multi-stage project that includes a wide range of operations. At the same time, there are standards for the technology of electrical work, which prescribe not only the rules for solving certain problems, but also safety requirements, as well as environmental protection.
The meaning of the production of electrical installation is to provide consumers with electricity. Through the channels of energy carriers, the current is delivered to the point of its reception with further use for its intended purpose. At each stage of the movement of electric current from the stationits development to the direct consumer can be carried out certain types of work of this kind. For example, in the book "Technology of electrical work" by V. M. Nesterenko, a wide coverage of the infrastructure of transmission networks is proposed, taking into account the construction of substations and high-voltage networks. In the most popular sense, however, electrical installation is still associated with operations that are performed within the infrastructure of an electrical panel - an apartment / house. This circuit, in particular, performs the most common operations for laying electrical wiring, installing sockets, electrical appliances, protective devices, etc.
With a wider coverage of electrical work, it is necessary to consider the activities that are used on the lines of backbone networks with transformers, energy conversion and distribution units. Within the framework of the general technology of electrical work, operations for connecting networks, installing substations and putting equipment into operation are united by the regulatory framework, however, in each case, the nature of the activities performed has its own nuances in terms of execution rules. Thus, the installation of a main power system node does involve construction work with the connection of special equipment and the construction of a foundation for functional blocks. In contrast, the installation of the simplest lighting device requires only a few minutes and basic skills in handling power tools.
General wiring technology
Regardless of the target on which the installation is being carried out and the subject of installation, the work is carried out on the basis ofprepared design solution. Even within the framework of minor operations, a conscientious performer uses a scheme, instruction or general regulatory documentation in his work, which allows him to ensure the proper quality of the result. The choice of technology for electrical work is also determined in the process of creating a project. Based on the principles of economic feasibility, energy efficiency and safety, the chief engineer determines the most appropriate way to solve the problem with optimal parameters. At this stage, in particular, questions about the method of laying the cable, the equipment used, the number of workers, etc. can be resolved.
The technical part of the work is directly related to the installation and, in turn, is divided into two stages. At the first, the technology for performing electrical work involves the installation of fasteners and load-bearing devices, which in principle allow solving the problem. For example, in the case of large-scale power systems, this stage will be expressed in the construction of the foundation and the installation of a frame for the technical room. When installing the switchboard at the same stage, the support elements will be fastened to the wall, and the installation of the socket will require screwing the fixing devices into the prepared niche.
The second stage of installation is reduced to the direct installation / placement of an element of the power system or consuming equipment on a specific section of the supply line, as well as to its connection. Again, the nature of the implementation of this stage will depend ondesign technology of work. Electrical work in relation to transformer substations, for example, is organized in order to fill the working blocks of the power system with functional equipment. To optimize installation and connection processes, manufacturers of electrical installations have long been developing special modules for integrating electrical devices for the corresponding purpose in a lightweight format. These can be cells and sections for input switches, feeders, switchgears, elements of a converter unit, relay protection, etc. To ensure convenient connection, electrical collector groups, splitters, blocks and other components can be used, which provide compact devices for fixing and connecting wires.
Wiring Tools & Consumables
There are several groups of technical means that are used in the installation of electrical networks and their equipment. Specific kits and consumables that will be used in the installation process, again, are determined by the design decision. The universal tools with which the implementation of electrical work is carried out include the following:
- Keys for installing electrical cabinets.
- Round and thin nose pliers.
- Strippers and other cable strippers.
- Cable Cutters.
- Soldering irons.
- Press tongs.
- Electrical tweezers.
Also locksmith-electrician works with devices for measuring network indicators. This group includes multimeters and testers, as well as specialized instruments like voltmeters and ammeters.
As for consumables, the technology of electrical work, depending on the conditions of the project, may include the use of the following auxiliary accessories:
- DIN rails.
- Insulating tape.
- Cable channels and boxes.
- Clamps and terminals.
- Metal hose.
- Distribution devices.
- Brackets and electrical masts.
- PVC pipes and wire protection profiles.
- Trays and traverses for cable placement.
Installation of electrical substations
One of the first critical nodes on the way of transporting electricity from a current source (NPP, TPP, HPP, etc.) is an integrated transformer substation. With its technical arrangement, construction and installation activities are carried out in the following general sequence:
- Preparing the site for work.
- Transportation of building structures and equipment.
- Installation of the substation frame with modules for equipment installation.
- Installation and connection of electrical equipment.
Directly, the technology for the production of electrical work is implemented from the moment the construction of the station buildings and its revision are completed. Furtherthe installation of nodes with voltage winding leads, the connection of automatic machines and switchgears begins. During installation, contact busbars, compression plates with plugs and other electrical fittings are used, due to which the infrastructure of the transformer is formed.
Technologies for mounting overhead power lines
From the substation to other functional nodes of the power grid for distribution, conversion or direct supply of consumers is a power line. As a subject of installation, a self-supporting insulated wire is used, which is pulled over a certain distance. The phased implementation of the technology of electrical work of this type can be represented as follows:
- Fixing the bandage tape on the bearing support. Such tapes are necessary to hold the fastening hooks. They are passed through special holes in the hooks, after which they are pulled and fixed with braces.
- Rolling out the wire. By the time this operation is performed, special rollers must be prepared on the aforementioned hooks to pass the cable. The wires are led from a special drum from rollers on one pole to another. The ends of the wires are attached with grip-stockings and are regulated by traction cables.
- Tightening the wire. According to regulatory requirements, the distances between the poles should not exceed 50 m. This is necessary so that the line does not sag. In modern technologies for performing electrical work, for optimal tension of the power line, they usea combination of a hand winch and a carabiner. At the same time, specific indicators of effort are controlled using a dynamometer.
Earthing as part of electrical work
During operation, bare surfaces may form in different parts of the power supply lines, which are dangerous for people and animals. In the complex of protective measures that insure against such situations, the method of grounding the electrical circuit is used. Its essence lies in the fact that the part of the power system that is energized is connected to the ground, thereby reducing the ability of current resistance in case of accidental contact with other objects. In the same book "Technology of electrical work" by Nesterenko V.M., it is proposed to consider grounding devices not just as a conductor for a specific circuit or equipment surface, but as a general integrated solution for connecting the entire local power grid to the ground surface. What does it mean? The function of wire elements is performed not only by a random metal object or wire, but by an electrical installation previously calculated in the project, which has a connection to the ground. This solution has two technological features:
- Technically formed by special electrodes that increase the protective function of grounding.
- From the side of connection to the target equipment or network section, it is assumed not a single input, but a group of modules or a block, part of the connecting grooves of which is always free. That is, if it is necessary to ground a new circuit orequipment, it is enough to draw a line from it to the introductory group. This is usually done via a PE bus standardized for protective wiring.
Installation of the electrical panel and its equipment
Electrical panel or cabinet performs the tasks of distributing and receiving electricity to supply end consumers. Initially, a wiring diagram is planned and the optimal place for installing this design is determined. Depending on the operating conditions of the electrical panel, certain requirements for external protection may be imposed on its body. For example, household structures have an IP65 protection class, which allows them to work stably even in high humidity conditions.
Mounting is carried out by means of brackets and anchors to the wall. That is, holes are prepared in advance for hinged fastening of the structure while maintaining the possibility of third-party cable entry. As for the internal filling, modern technologies of electrical work are guided by the individual assembly of the distributing power system of the shield. In special compartments, RCD protective devices and difautomats are installed for specific load indicators, which are determined in the design solution. It is mandatory to integrate modular automation, contactors and protection relays. More modern installations also provide additional functionality with digital meters and indicator lights.
Position of wiring, switches and sockets
From the electrical panel to the house or apartmentlocal wiring loops for power supply devices are already being laid. Posting is placed according to a previously prepared plan in an open or hidden format. In the first case, installation and assembly of cable channels may also be required, and in the second, wall chasing with the formation of channels for laying the line at a depth of 2-3 cm. Joints, turns and connections are made out of mounting boxes with contactors and a DIN rail.
After the completion of the cabling at the site of operation, sockets with wiring outlets should remain. They install sockets, switches and other electrical infrastructure devices. In this part, the technology of electrical work requires the installation of a junction box. It is provided for when organizing a new electrical wiring. This is a practical solution that will facilitate further work on connecting new electrical devices. The junction box is made of plastic and is mounted in the power cable output unit. Its internal filling contains small-format pads and distribution rails for connecting to razor wires leading to lighting devices, switches and other points of control and power consumption.
Technology of electrical work on ships
As is the case with the power supply of buildings, apartments and engineering structures, a project for the installation of electrical equipment and power delivery circuits is preliminarily developed for the ship. The main electrical installation activities in this case include the following:
- Across the entire route of laying the power line,placement of the wire, its cutting, termination and testing with checking the insulation after installation.
- The installation of targeted electrical equipment is being carried out at points of direct consumption.
- The main main channels are bayed and tied up in the zones of bottomhole sections. We can say that this is a backup wiring, which must be reliably protected from damage during inactivity.
- At the final stage, commissioning activities are carried out with measurements of the power grid and testing of the equipment.
Today, more and more often, parallel technology is used to perform electrical work on ships, according to which the external and internal organization of the power system is carried out simultaneously. This method is especially effective in the block layout of ships. It allows you to optimize the technological processes of installation, but it also has its drawbacks. For example, when implementing this method, a strict calculation of energy resources is necessary, since they can be simultaneously used in several functional areas. In addition, there are organizational problems with parallel wiring and connecting equipment in several units at once.
Installation of power systems as such, even with small amounts of work, is a complex of technical operations. This is due to the fact that the process of energy supply itself involves a number of objects for various purposes. Even the technology of ship electrical work withinlimited space at least involves a series of actions with cable laying. And this applies only to the direct organization of consumer food infrastructure. In the process of operation, constant monitoring of the quality of connections, the state of insulation and protective equipment will be required. And all this against the background of the dependence of the created infrastructure on the stability of the main source of electricity.