An electrical drawing, a type of technical drawing, shows information about power, lighting, and communication for an engineering or architectural project. Any electrical working drawing consists of “lines, symbols, dimensions, and notations to accurately convey an engineering’s design to the workers, who install the electrical system on the job”.
A complete set of working drawings for the average electrical system in large projects usually consists of:
- A plot plan showing the building’s location and outside electrical wiring
- Floor plans showing the location of electrical systems on every floor
- Power-riser diagrams showing panel boards
- Control wiring schemes
- Schedules and other information in combination with construction drawings.
Electrical drafters prepare wiring and layout diagrams used by workers who erect, install, and repair electrical equipment and wiring in communication centers, power plants, electrical distribution systems, and buildings.
Drafters prepare technical drawings and plans, which are used to build everything from manufactured products such as toys, toasters, industrial machinery, and spacecraft to structures such as houses, office buildings, and oil and gas pipelines.
In the past, drafters sat at drawing boards and used pencils, pens, compasses, protractors, triangles, and other drafting devices to prepare a drawing by hand. Now, most drafters use Computer Aided Design and Drafting (CADD) systems to prepare drawings. Consequently, some drafters may be referred to as CADD operators.
With CADD systems, drafters can create and store drawings electronically so that they can be viewed, printed, or programmed directly into automated manufacturing systems. CADD systems also permit drafters to quickly prepare variations of a design. Although drafters use CADD extensively, it is only a tool. Drafters still need knowledge of traditional drafting techniques, in addition to CADD skills. Despite the nearly universal use of CADD systems, manual drafting and sketching are used in certain applications.
Drafters’ drawings provide visual guidelines and show how to construct a product or structure. Drawings include technical details and specify dimensions, materials, and procedures. Drafters fill in technical details using drawings, rough sketches, specifications, and calculations made by engineers, surveyors, architects, or scientists. For example, drafters use their knowledge of standardized building techniques to draw in the details of a structure. Some use their understanding of engineering and manufacturing theory and standards to draw the parts of a machine; they determine design elements, such as the numbers and kinds of fasteners needed to assemble the machine. Drafters use technical handbooks, tables, calculators, and computers to complete their work.
- Aeronautical drafters prepare engineering drawings detailing plans and specifications used in the manufacture of aircraft, missiles, and related parts.
- Architectural drafters draw architectural and structural features of buildings and other structures. These workers may specialize in a type of structure, such as residential or commercial, or in a kind of material used, such as reinforced concrete, masonry, steel, or timber.
- Civil drafters prepare drawings and topographical and relief maps used in major construction or civil engineering projects, such as highways, bridges, pipelines, flood control projects, and water and sewage systems.
- Electrical drafters prepare wiring and layout diagrams used by workers who erect, install, and repair electrical equipment and wiring in communication centers, power plants, electrical distribution systems, and buildings.
- Electronics drafters draw wiring diagrams, circuit board assembly diagrams, schematics, and layout drawings used in the manufacture, installation, and repair of electronic devices and components.
- Mechanical drafters prepare drawings showing the detail and assembly of a wide variety of machinery and mechanical devices, indicating dimensions, fastening methods, and other requirements.
- Process piping or pipeline drafters prepare drawings used in the layout, construction, and operation of oil and gas fields, refineries, chemical plants, and process piping systems.
Drafters usually work in comfortable offices. They may sit at adjustable drawing boards or drafting tables when doing manual drawings, although most drafters work at computer terminals much of the time. Because they spend long periods in front of computers doing detailed work, drafters may be susceptible to eyestrain, back discomfort, and hand and wrist problems. Most drafters work a standard 40-hour week; only a small number work part time.
Education and training
High school courses in mathematics, science, computer technology, design, computer graphics, and, where available, drafting are useful for people considering a drafting career. Employers prefer applicants who have also completed training after high school at a technical institute, community college, or 4-year college or university.
The kind and quality of drafting training programs vary considerably so prospective students should be careful in selecting a program. They should contact prospective employers to ask which schools they prefer and contact schools to ask for information about the kinds of jobs their graduates have, the type and condition of instructional facilities and equipment, and teacher qualifications.
Technical institutes offer intensive technical training, but they provide a less general education than do community colleges. Either certificates or diplomas may be awarded. Many technical institutes offer 2-year associate degree programs, which are similar to, or part of, the programs offered by community colleges or State university systems. Their programs vary considerably in length and in the type of courses offered. Some public vocational-technical schools serve local students and emphasize the type of training preferred by local employers. Most require a high school diploma or its equivalent for admission. Other technical institutes are run by private, often for-profit, organizations sometimes called proprietary schools.
Design engineer is a general term that covers multiple engineering disciplines including but not limited to electrical, mechanical and civil engineering, architectural engineers in the U.S. and building engineers in the U.K.
The design engineer is distinguished from the designer/drafter by virtue of the fact that a design engineer sets the direction of the design effort and does the most complex parts of design. The design engineer usually leads the project, designing the overall frameworks and the most far reaching parts, and directing the designers/drafters on sub-system design on the project’s more routine parts as necessary. He/she may work with industrial designers and marketing to develop the product concept and specifications and directs the design effort from that point. Products are usually designed with input from a number of sources such as manufacturing, purchasing, tool making and packaging engineering.
In many engineering areas, a distinction is made between the design engineer and the planning engineer in design. Planning engineers are more concerned with designing on a more systems engineering level, and overlaps onto the operational side are often necessary. Design engineers, in contrast, are more concerned with designing a particular new product or system. Analysis is important for planning engineers, while synthesis is paramount for design engineers.
When the design involves public safety, the design engineer is usually required to be licensed, for example a Professional Engineer in the U.S. There is usually an ‘industrial exemption’ for design engineers working on project internal to companies.
Design Engineer Tasks
The design engineer may direct a team of designers to create the drawings necessary for prototyping and production, or in the case of buildings, for construction. However, with the advent of CAD and solid modeling software (SolidWorks, Solid Edge, Autodesk Inventor, Pro/ENGINEER, NX, CATIA, etc, for example) the design engineer may create the drawings him or herself.
The next responsibility of many design engineers is prototyping. A model of the product is created and reviewed. Prototypes are usually functional and non-functional. Functional prototypes are used for testing and the non-functional are used for form and fit checking. This stage is where design flaws are found and corrected, and tooling, manufacturing fixtures, and packaging are developed.
Once the prototype is finalized, after many iterations, the next step is preproduction. The design engineer, working with a manufacturing engineer and a quality engineer reviews an initial run of components and assemblies for design compliance. This is often determined through statistical process control. Variations in the product are correlated to aspects of the process and eliminated. The most common metric used is the process capability index Cpk. A Cpk of 1.0 is considered the baseline acceptance for full production go-ahead.
The design engineer may follow the product and make requested changes and corrections throughout the life of the product. This is referred to as “cradle to grave” engineering.