Electrical system design

Last updated

Electrical system design is the design of electrical systems. This can be as simple as a flashlight cell connected through two wires to a light bulb or as involved as the Space Shuttle. Electrical systems are groups of electrical components connected to carry out some operation. Often the systems are combined with other systems. They might be subsystems of larger systems and have subsystems of their own. For example, a subway rapid transit electrical system is composed of the wayside electrical power supply, wayside control system, and the electrical systems of each transit car. Each transit car’s electrical system is a subsystem of the subway system. Inside of each transit car there are also subsystems, such as the car climate control system.

Design

The following would be appropriate for the design of a moderate to large electrical system.

  1. A specification document is written. It probably would have been written by the customer. The specification document states in plain language and numerical detail what the customer expects. If it is well written, it will be used as a reference throughout the electrical system design.
  2. A functional specification (design) document that goes into more technical details may be created. It uses the specification document as its basis. Here calculations may be used or referenced to support design decisions.
  3. Functional diagrams may be made. These use block diagrams indicating information and electrical power flow from component to component. They are similar to the functional flow block diagrams used with computer programs.
  4. Schematic diagrams showing the electrical interconnections between the components are made. They may not show all the conductors and termination points. Except for one-line diagrams, this should show all the circuit nodes. One-line diagrams represent the three or four conductors of three-phase power circuits with one line.
  5. Wiring diagrams are sometimes made. These show and name the termination points and names of each conductor. In some systems, enough information can be put onto the schematics so that wiring diagrams are not needed.
  6. Physically smaller systems that are built many times may use a cable harness. A full-sized to-scale wiring diagram can be made of a cable harness. This wiring diagram can then be laid on a peg board and used to guide the construction of more cable harnesses. Harnesses can be inserted into their equipment as an assembly. Cable harnesses that are reused many times, like automobile wiring harnesses, are created with automated machinery.
  7. A wire list is made in spreadsheet or list format. It shows the electrical assembly people what wires are to be connected and to where. When it is printed out on paper, it is easy for the assembly people to check off conductors as they are connected. The wire list contains at a minimum each wire name, terminal name, and wire model number or gage. It may also contain the wire termination device model numbers, voltage classes, conductor class (high-voltage, medium voltage, or control wiring), etc.

Related Research Articles

<span class="mw-page-title-main">Ground (electricity)</span> Reference point in an electrical circuit from which voltages are measured

In electrical engineering, ground or earth is a reference point in an electrical circuit from which voltages are measured, a common return path for electric current, or a direct physical connection to the Earth.

<span class="mw-page-title-main">Schematic</span> Representation of a system using abstract graphic symbols

A schematic, or schematic diagram, is a designed representation of the elements of a system using abstract, graphic symbols rather than realistic pictures. A schematic usually omits all details that are not relevant to the key information the schematic is intended to convey, and may include oversimplified elements in order to make this essential meaning easier to grasp, as well as additional organization of the information.

<span class="mw-page-title-main">Electrical cable</span> Assembly of one or more wires running side by side or bundled

An electrical cable is an assembly of one or more wires running side by side or bundled, which is used to carry electric current.

<span class="mw-page-title-main">Electrical connector</span> Device used to join electrical conductors

Components of an electrical circuit are electrically connected if an electric current can run between them through an electrical conductor. An electrical connector is an electromechanical device used to create an electrical connection between parts of an electrical circuit, or between different electrical circuits, thereby joining them into a larger circuit. Most electrical connectors have a gender – i.e. the male component, called a plug, connects to the female component, or socket. The connection may be removable, require a tool for assembly and removal, or serve as a permanent electrical joint between two points. An adapter can be used to join dissimilar connectors.

A Controller Area Network is a robust vehicle bus standard designed to allow microcontrollers and devices to communicate with each other's applications without a host computer. It is a message-based protocol, designed originally for multiplex electrical wiring within automobiles to save on copper, but it can also be used in many other contexts. For each device, the data in a frame is transmitted serially but in such a way that if more than one device transmits at the same time, the highest priority device can continue while the others back off. Frames are received by all devices, including by the transmitting device.

Electrical wiring in North America follows the regulations and standards applicable at the installation location. It is also designed to provide proper function, and is also influenced by history and traditions of the location installation.

<span class="mw-page-title-main">Circuit diagram</span> Graphical representation of an electrical circuit

A circuit diagram is a graphical representation of an electrical circuit. A pictorial circuit diagram uses simple images of components, while a schematic diagram shows the components and interconnections of the circuit using standardized symbolic representations. The presentation of the interconnections between circuit components in the schematic diagram does not necessarily correspond to the physical arrangements in the finished device.

In an electrical system, a ground loop or earth loop occurs when two points of a circuit are intended to have the same ground reference potential but instead have a different potential between them. This is typically caused when enough current is flowing in the connection between the two ground points to produce a voltage drop and cause two points to be at different potentials. Current may be produced in a circular ground connection by electromagnetic induction.

Ground and neutral are circuit conductors used in alternating current electrical systems. The ground circuit is connected to earth, and neutral circuit is usually connected to ground. As the neutral point of an electrical supply system is often connected to earth ground, ground and neutral are closely related. Under certain conditions, a conductor used to connect to a system neutral is also used for grounding (earthing) of equipment and structures. Current carried on a grounding conductor can result in objectionable or dangerous voltages appearing on equipment enclosures, so the installation of grounding conductors and neutral conductors is carefully defined in electrical regulations. Where a neutral conductor is used also to connect equipment enclosures to earth, care must be taken that the neutral conductor never rises to a high voltage with respect to local ground.

<span class="mw-page-title-main">Electrical wiring</span> Electrical installation of cabling

Electrical wiring is an electrical installation of cabling and associated devices such as switches, distribution boards, sockets, and light fittings in a structure.

Electrical wiring in the United Kingdom is commonly understood to be an electrical installation for operation by end users within domestic, commercial, industrial, and other buildings, and also in special installations and locations, such as marinas or caravan parks. It does not normally cover the transmission or distribution of electricity to them.

<span class="mw-page-title-main">Power cable</span> Bundle of wires for transmitting electricity

A power cable is an electrical cable, an assembly of one or more electrical conductors, usually held together with an overall sheath. The assembly is used for transmission of electrical power. Power cables may be installed as permanent wiring within buildings, buried in the ground, run overhead, or exposed. Power cables that are bundled inside thermoplastic sheathing and that are intended to be run inside a building are known as NM-B.

<span class="mw-page-title-main">Structured cabling</span> Telecommunications cabling infrastructure

In telecommunications, structured cabling is building or campus cabling infrastructure that consists of a number of standardized smaller elements called subsystems. Structured cabling components include twisted pair and optical cabling, patch panels and patch cables.

An earthing system or grounding system (US) connects specific parts of an electric power system with the ground, typically the Earth's conductive surface, for safety and functional purposes. The choice of earthing system can affect the safety and electromagnetic compatibility of the installation. Regulations for earthing systems vary among countries, though most follow the recommendations of the International Electrotechnical Commission (IEC). Regulations may identify special cases for earthing in mines, in patient care areas, or in hazardous areas of industrial plants.

<span class="mw-page-title-main">Cable harness</span>

A cable harness, also known as a wire harness, wiring harness, cable assembly, wiring assembly or wiring loom, is an assembly of electrical cables or wires which transmit signals or electrical power. The cables are bound together by a durable material such as rubber, vinyl, electrical tape, conduit, a weave of extruded string, or a combination thereof.

In an electric power system, a fault or fault current is any abnormal electric current. For example, a short circuit is a fault in which a live wire touches a neutral or ground wire. An open-circuit fault occurs if a circuit is interrupted by a failure of a current-carrying wire or a blown fuse or circuit breaker. In three-phase systems, a fault may involve one or more phases and ground, or may occur only between phases. In a "ground fault" or "earth fault", current flows into the earth. The prospective short-circuit current of a predictable fault can be calculated for most situations. In power systems, protective devices can detect fault conditions and operate circuit breakers and other devices to limit the loss of service due to a failure.

<span class="mw-page-title-main">British telephone socket</span>

British telephone sockets were introduced in their current plug and socket form on 19 November 1981 by British Telecom to allow subscribers to connect their own telephones. The connectors are specified in British Standard BS 6312. Electrical characteristics of the telephone interface are specified by individual network operators, e.g. in British Telecom's SIN 351. Electrical characteristics required of British telephones used to be specified in BS 6305.

<span class="mw-page-title-main">Pothead</span> High-voltage electrical connection device

A pothead is a type of insulated electrical terminal used for transitioning between overhead line and underground high-voltage cable or for connecting overhead wiring to equipment like transformers. Its name comes from the process of potting or encapsulation of the conductors inside the terminal's insulating bushing.

<span class="mw-page-title-main">Copper conductor</span> Electrical wire or other conductor made of copper

Copper has been used in electrical wiring since the invention of the electromagnet and the telegraph in the 1820s. The invention of the telephone in 1876 created further demand for copper wire as an electrical conductor.

References