A graphic symbol represents the function of a part in the
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
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
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
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
TYPES OF DRAWINGS AND
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
architectural, mechanical, and
Regardless of the category, working drawings
serve several functions:
They provide a basis for making material, labor,
and equipment estimates before construction
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