A graphic symbol represents the function of a part in the circuit.
Qualifying symbols may be added to symbols when the special characteristic is important to the function of the device and aids in the understanding of the overall function performed. For example, connection symbols shown in column 1 of figure 2-6 are headed "Qualifying Symbols." They are combined with transformer symbols shown further on in the figure.
Some symbols may be similar or identical to other symbols but have different meanings. Only one meaning will apply to a specific symbol used on a diagram. Notes, asterisks, and flagging techniques may be used with symbols having multiple meanings. A tabulation listing the intended meanings should be provided.
Except where noted, the orientation of a symbol on a drawing does not alter the meaning of the symbol.
When installing electrical systems and circuits, you will sometimes have to exchange information about your job with others. A freehand sketch can be an accurate and a concise way to communicate this information.
This type of drawing is informal in character, may or may not be drawn to scale, and need not follow any particular format. A sketch can be used in many ways. One example of where to use a sketch is to show a field change that must be made. Nomatterhowwellaproject is planned, occasionally field changes have to be made. You may see that a field change is necessary because a conduit run cannot practically be routed according to the approved drawing or plan. You can make a freehand sketch showing only what has to be changed. The sketch may include dimensions, symbols, and other information needed to convey your idea of the required change to someone else (like the project supervisor or project chief).
The types of drawings to be discussed here include working drawings, architectural drawings, mechanical drawings, shop drawings, and electrical diagrams.
A construction drawing is any drawing that furnishes the information required by the craftsmen to rough in equipment or erect a structure. The terms working drawings and construction drawings are sometimes used interchangeably. Information presented in a set of working drawings, along with the specifications, should be complete so the craftsman who uses them will require no further information. Working drawings show the size, quantity, location, and relationship of the building parts. Generally, working drawings may be divided into three main categories: architectural, mechanical, and electrical.
Regardless of the category, working drawings serve several functions:
They provide a basis for making material, labor, and equipment estimates before construction starts.
They give instructions for construction, showing the sixes and location of the various parts.
They provide a means of coordination between the different ratings.
They complement the specifications; one source of information is incomplete without the other when drawings are used for construction work.
Architectural drawings consist of all the drawings that describe the structural members of the building and their relationship to each other. This includes foundation plans, floor plans, framing plans, elevations, sections, details, schedules, and bills of materials.
A plan is actually a part of the architectural drawing that represents a view of the project from above. Two types of plans will be discussed here: plot plans and floor plans.Continue Reading