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Figure 6-24.—Pilot wire control of multiple-lighting circuits | Up
Construction Electrician Basic - Electricity handbook for electricians | Next
Small Appliance Branch Circuit |
CHAPTER 7
ELECTRICAL APPLIANCES, TEST EQUIPMENT,
MOTORS, AND CONTROLLERS
In this chapter we will discuss the installation,
principles of operation, troubleshooting, and repair of
electrical appliances, motors, and controllers. We will
also discuss the principles of operation and use of test
equipment. Some of the appliances that we will discuss
are washing machines, clothes dryers, electric ranges,
and hot-water heaters. No matter what type of
command you are assigned to, whether it be a mobile
construction battalion, public works, or construction
battalion unit, you, as a Construction Electrician (CE),
will be called upon to install, troubleshoot, and repair
various appliances.
The information on various representative
appliances applies generally to a number of different
makes and models. You can use the repair procedures
for other appliances that you will service. To
troubleshoot and repair appliances effectively, you must
understand the principles of operation that apply to
them.
Throughout this chapter you will see references to
the National Electrical Code© (NEC©). Look up each
article and read it. More specific information is
contained there than will be discussed in this chapter.
You will need this specific information to do your job
properly.
Appliances are of three types: fixed, portable, and
stationary. Fixed appliances are installed at a specific
location. Once installed, they become permanent.
Examples of fixed appliances are hot-water heaters and
central air-conditioning units. Portable appliances can
be moved from place to place. Examples of these are
food mixers and toasters. Stationary appliances are not
easily moved from place to place in normal use.
Examples of these are window air-conditioning units
and refrigerators.
The components of appliances range from a simple
ON/OFF switch to more essential components, such as
motors, pumps, and temperature control switches.
There are components in similar appliances that work
on the same principle and, in many cases, the majority
of the parts from one type of appliance can be
interchanged with another. The only difference in many
appliances is the housing and brand name. The
important point to remember is when a particular brand
name appliance is inoperative because of a broken
component, you may be able to use a component from
another brand name appliance to get the appliance back
into operation.
APPLIANCE INSTALLATION
REQUIREMENTS
Many factors affect the installation of appliances.
We will discuss some of the more important of factors in
this section, to include; connection to power, means of
disconnection, branch circuits, and installation by type
of appliance
Generally, appliances may be connected only to a
receptacle with the same rating as the appliance. A
standard 110-volt, 15-ampere duplex outlet may supply
a single 15-ampere fixed or a 12-ampere branch circuit.
On new construction projects all 15- and 20-ampere
receptacles must be of the grounding type. (Refer to
NEC©, Article 250.) Most household appliances, such
as toasters, flat irons, waffle irons, refrigerators, and
portable ovens, are rated at less than 12 amperes, so they
may be used in the standard outlet on a 110-volt, 15-
ampere circuit.
Each appliance should have a means for
disconnection from all ungrounded conductors. Since
there are different types of appliances, naturally there
are different disconnecting means.
For fixed or stationary appliances that are not rated
300 voltamperes or 1/8 horsepower (93.3 watts), the
branch-circuit overcurrent device can serve as the
disconnecting means. For an appliance rated greater
than 300 voltamperes or 1/8 horsepower (93.3 watts),
the circuit breaker may serve as the disconnecting
means if it is within sight from the appliance or is
capable of being locked in the open position. On
portable appliances, an attachment plug and receptacle
may serve as a disconnecting means; this disconnection
arrangement may include household ranges and clothes
dryers. The amperage rating of the receptacle should
not be less than the rating of the appliance, unless so
authorized by the NEC©. Attachment plugs and
connectors should conform to Article 422 of the NEC©.
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