Connecting a house, a transport facility or an engineering structure to a power supply system involves a number of electrical 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, including a wide list of operations. At the same time, there are standards for the technology of electrical work, which prescribe not only the rules for solving particular problems, but also safety requirements, as well as environmental protection.
Basics of electrical work
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 as intended. At each stage of the movement of electric current from the station of its generation to the direct consumer, certain types of work of this kind can be carried out. For example, in the book “Electrical Installation Technology” 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, wiring is nevertheless associated with operations that are carried out as part of the infrastructure of the electric panel - apartment / house. On this circuit, in particular, the most common operations are carried out for laying electrical wiring, installing sockets, electrical appliances, protective devices, etc.
With a wider scope of electrical work, it is also necessary to consider measures that are used on the lines of main networks with transformers, energy conversion and distribution units. Within the framework of the general technology of electrical installation work, operations on connecting networks, installing substations and putting equipment into operation are united by the regulatory framework, however, in each case, the nature of the measures taken has its own nuances in terms of execution rules. So, the installation of the main power system node involves the implementation of construction work with the connection of special equipment and the construction of the foundation for functional blocks. Conversely, the installation of a simple lighting device requires only a few minutes and basic skills in handling electric tools.
General technology of electrical work
Regardless of the target object, on which the installation is carried out, and the installation subject, the work is carried out on the basis of the prepared design solution. Even within the framework of minor operations, a conscientious contractor uses in the work a scheme, instruction or general regulatory documentation that 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 the project. The chief engineer on the basis of the principles of economic feasibility, energy efficiency and safety determines the most acceptable way to solve the problem with optimal parameters. At this stage, in particular, questions can be solved about the method of laying the cable, the equipment used, the number of workers, etc.
The technical part of the work is directly related to installation and, in turn, is divided into two stages. At the first, the technology for performing electrical work involves the installation of fasteners and supporting devices that, in principle, allow us to solve the problem. For example, in the case of large-format power systems, this stage will be expressed in the construction of the foundation and installation of the frame for the technical room. When installing the switchboard at the same stage, the fastening of the load-bearing elements to the wall will be implemented, and installing the outlet will require fixing devices to be screwed into the prepared niche.
The second stage of installation is reduced to the direct installation / placement of a power system element 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 phase will depend on the design technology of the 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 the integration of electrical devices of the corresponding purpose in a lightweight format. These can be cells and sections for opening switches, feeders, switchgear, elements of the converter unit, relay protection equipment, etc. To ensure convenient connection, electrical collector groups, splitters, blocks, and other components that provide compact devices for fixing and connecting wires.
Electrical Tools and Supplies
There are several groups of technical equipment that are used in the installation of electric networks and their equipment. The 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 implemented include the following:
- Keys for installing electrical cabinets.
- Round-nose pliers and thin-nose pliers.
- Pliers.
- Strippers and other cable strippers.
- Cable cutters.
- Soldering irons.
- Press pliers.
- Wiring tweezers.
In addition, a fitter works with devices for measuring network performance. This group includes multimeters and testers, as well as specialized tools 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 ducts.
- Insulating agents.
- Clips and terminals.
- Metal hoses.
- Switchgears.
- Brackets and wiring masts.
- PVC pipes and profiles to protect wiring.
- Trays and traverses for placement of cables.
Installation of electrical substations
One of the first critical nodes on the way of transporting electricity from a current source (nuclear power plants, thermal power plants, hydroelectric power stations, etc.) is a complex transformer substation. With its technical structure, construction and installation activities are carried out in the following general sequence:
- Preparation of the site for work.
- Transportation of building structures and equipment.
- Installation of the substation frame with modules for the installation of equipment.
- Installation and connection of electrical equipment.
- Commissioning works.
Directly, the technology for the production of electrical work has been implemented since the completion of the construction of the station buildings and its revision. Next, the installation of nodes with the terminals of the voltage windings, the connection of automatic machines and switchgears begins. During installation, contact tires, compression plates with plugs and other electrical fittings are used, due to which the transformer infrastructure is formed.
Technologies for installing overhead power lines
From the substation to other functional nodes of the power grid for the distribution, conversion or direct supply of consumers is a power line. As the subject of installation, a self-supporting insulated wire is used, which stretches at a certain distance. The phased implementation of this type of electrical installation technology can be represented as follows:
- Fixing the bandage tape on the supporting support. Such tapes are necessary to hold the mounting hooks. They are passed through special holes in the hooks, after which they are pulled and fixed with clips.
- Rolling the electric wire. By the time this operation is completed, special rollers must be prepared for the passage of the cable on the above hooks. Wires are conducted from a special drum from the rollers on one column to another. The ends of the wires are fixed with gripping stockings and are regulated by traction cables.
- Pulling the wire. According to regulatory requirements, the distance between the posts should not exceed 50 m. This is necessary so that the line does not sag. In modern technologies for performing electrical work, for the optimal tension of the power line, a combination of a manual winch and a carbine is used. In this case, specific indicators of effort are controlled using a dynamometer.
Grounding as part of electrical work
In different parts of the power supply lines during operation, bare surfaces that are dangerous to people and animals can form. In the complex of protective measures insuring 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, which 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, “Electrical Installation Work Technology,” V. M. Nesterenko proposes to consider grounding devices not just as a conductor for a particular 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 the wire elements is performed not only by a random metal object or wire, but by an electrical installation previously calculated in the project that has a conclusion to the ground. This solution has two technological features:
- Technically formed by special electrodes that increase the protective function of grounding.
- On the part of connecting to the target equipment or network section, it is assumed not a single input, but a group of modules or block, part of the connecting grooves of which is always free. That is, if it is necessary to ground a new circuit or equipment, it is enough to draw a line from it to the input group. This is usually done through the PE bus, standardized for the needs of protective wiring.
Installation of the electrical panel and its equipment
An electric panel or cabinet performs the tasks of distributing and receiving electricity to supply end consumers. Initially, a wiring diagram is planned and the optimal location for installing this design is determined. Depending on the operating conditions of the electrical panel, one or another of the requirements for external protection may be presented to its body. For example, household structures have a protection class of IP65, which allows them to work stably even in high humidity.
Installation is via brackets and wall anchors. That is, holes for hinged mounting of the structure are prepared in advance, while maintaining the possibility of third-party cabling. As for the internal content, the modern technologies of electrical installation work are guided by the individual assembly of the distributing power system of the shield. In special compartments, protective devices for residual current devices and difratomata are installed for specific load indicators, which are determined in the design decision. It is mandatory to integrate modular automation, contactors and protection relays. More modern installations also provide additional functionality with digital measuring devices and light indicators.
Placement of wiring, switches and sockets
From the electrical panel to the house or apartment, local wiring circuits for power supply devices are already laid. Posting is placed according to a previously prepared plan in open or hidden format. In the first case, installation and assembly of cable channels may also be required, and in the second case, the walls should be shredded to form channels for laying a line at a depth of 2-3 cm. The joints, turns and connections are formed by mounting boxes with contactors and a DIN rail.
After completing the cabling, the jacks with wiring outputs should remain at the facility. They install sockets, switches and other devices of the electrical infrastructure. In this part, the technology of electrical work requires the installation of a junction box. It is provided for when organizing new wiring. This is a practical solution that will facilitate further work on connecting new electrical devices. The junction box is made of plastic and mounted in the output node of the power cable. Its internal filling contains small-sized blocks and distribution rails for connection with adjustable wires leading to lighting devices, switches and other points of control and energy consumption.
Technology of electrical work on ships
As in the case of the energy supply of buildings, apartments and engineering structures, a project for the installation of electrical equipment and power supply circuits is preliminarily developed for the vessel. The main electrical installation activities in this case include the following:
- Along the entire route of laying the power line, the wire is placed, cut, terminated and tested with insulation check after installation.
- At points of direct consumption, the installation of the target electrical equipment is carried out.
- The main main canals cove and tie up in the zones of bottom-hole sites. We can say this is a backup wiring, which for the period of inactivity should be reliably protected from damage.
- At the final stage, commissioning activities are carried out with measurements of the power supply and testing the operation of the equipment.
Today, a parallel technology for performing electrical installation work on ships is increasingly being used, 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 installation processes, but 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 zones. In addition, there are organizational problems with the parallel installation of wiring and equipment connection in several blocks at once.
Conclusion
Installation of energy systems as such, even with small amounts of work, is a complex of technical operations. This is due to the fact that the energy supply process itself involves a number of objects for various purposes. Even the technology of marine electrical work within a limited space at least provides for a series of actions with cable laying. And this applies only to the direct organization of consumer nutrition infrastructure. In the process of operation, constant monitoring of the quality of the joints, the state of insulation and protective equipment will be necessary. And all this against the background of the dependence of the created infrastructure on the stability of the main source of electricity.