Figure 9-21.-Three-way switch circuit.
Figure 9-22.-Four-way switch circuit.
Note that three- and four-way switches can be
used as single-pole switches, and four-way
switches can be used as three-way switches. Some
activities may install all small-wattage, four-way
switches for all lighting circuits to reduce their
inventories. However, three- and four-way
switches are usually larger than single-pole
switches and take up more box room. The size
of a switch depends on its ampacity (related
maximum amperage). The ampacity and maxi-
mum allowable voltage are stamped on the switch.
The electrical information and layouts in
construction drawings, just as the mechanical
plan, are generally superimposed on the
building plan and the plot plan.
In this chapter, we will address electrical plans
as those drawings that pertain to the ELECTRI-
CAL (POWER) DISTRIBUTION SYSTEM,
which indicate outside power lines and appurte-
nances for multibuilding installations, and the
INTERIOR ELECTRICAL WIRING SYSTEM.
As an EA3, the electrical layout for both light
and power is your main concern. You will be
required to draw electrical drawings and layouts
from notes, sketches, and specifications provided
by the designing engineer. Although you are not
required to design the electrical wiring system, you
must be familiar with the methods, the symbols,
and the nomenclature, as well as the basic
functions of the components associated with
the electrical systems, its transmission and
distribution, and the circuits hookup. In addition,
you must also be familiar with the codes (both
NEC® and local) and standards and specifica-
tions, and be able to apply that knowledge in
drawing electrical plans.
STANDARDS AND SPECIFICATIONS
Because the safety of the electrical system is
of prime importance, it is imperative that all Navy
electrical installations ashore conform to rigid
standards and specifications. When preparing
construction drawings, the EAs, like the CES, are
required to follow the specifications issued by the
Naval Facilities Engineering Command (NAV-
FACENGCOM). In particular, an EA working
on electrical wiring and layout diagrams for
electrical plans should refer to the latest edition
of ANSI Y32.9 and ANSI Y14.15.
Code requirements and installation procedures
offer protection for the consumer against un-
skilled electrical labor. Among other functions,
the NEC® serves as a basis for limiting the type
and wiring to be used, the circuit size, the outlet
spacings, the conduit requirements, and the like.
In addition, local codes are also used when
separate electrical sections are applicable to the
locale in which the building will be built. Be
certain that you always have a copy of the latest
edition of the NEC® available for your use.
Similarly, all of the types of electrical
devices and fixtures included in the materials list
prepared for electrical plans are to meet certain
specifications and minimum requirements. An
independent organization called Underwriters