Builders when they build the forms. The conduit will be
placed in or through the form before the concrete is
Mechanical drawings include all drawings and
notes that have something to do with the water supply,
sewage, drainage, heating and ventilating,
refrigeration, air conditioning, and gas supply systems.
It may also include other drawings that are necessary to
present the system properly in relation to the other
portions of the project.
Shop drawings are drawings and related data used
to show some portion of the work prepared by the
construction contractor, manufacturer, distributor, or
supplier. Product data, such as brochures, illustrations,
standard schedules, performance charts, and other
information, are furnished by the contractor or the
manufacturer to show a material, product, or system for
some portion of the work. Engineering Aids are
sometimes required to draft shop drawings for minor
shop and field projects. These drawings may include
shop items, such as doors, cabinets, and small portable
buildings (prefabricated berthing quarters and
modifications of existing structures), or they may come
from portions of design drawings, specifications, or
freehand sketches given by the design engineer.
Working from a shop drawing is much like working
from other working drawings. You convert the ideas
you get from your interpretation of the lines and
symbols into the product represented by the drawing.
In addition to the construction drawings discussed
above, you will be working with other types of electrical
drawings or diagrams.
These drawings show the
arrangement and relationship of parts. Electrical
diagrams are usually used to show how the parts of one
or more pieces of equipment are wired together. There
are several types of these diagrams. They are similar,
yet different in some way. The short description of each
that follows should enable you to recognize their
The isometric diagram is not often seen in electrical
work. It may be used to show the electrical wiring
system in multilevel buildings. Appliances sometimes
have an isometric diagram glued to an access panel so
that it may be referred to for a quick look at an entire
wiring system. (See fig. 2-13.)
A block diagram is a simple drawing showing the
relationships of major parts of a wiring circuit or
system. Figure 2-14 shows a block diagram of a motor
control system You can easily see how it gets its name.
Sometimes the blocks are connected with only one line
that may represent one or more conductors or cables.
Either major or minor components or parts may be
represented by blocks. This type of diagram is often
used to show something of the relationship of
components in a power distribution system. The block
diagram provides little help in troubleshooting.
Figure 2-13.Isometric wiring diagram.