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(c) (NEC(c)). 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(c), 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(c). Attachment plugs and connectors should conform to Article 422 of the NEC(c).

Unit switches that are part of an appliance that disconnect all ungrounded conductors are permitted as the disconnecting means. Refer to Article 422 of the NEC(c) for other means of disconnection on the various types of occupancies. When you are grounding an appliance, refer to the NEC(c), Article 250. Any part of an appliance that may be energized must be grounded except for those mentioned within this article.

SMALL APPLIANCE BRANCH CIRCUIT A circuit that supplies electrical energy to one or more outlets to which appliances are to be connected is called an appliance branch circuit. These circuits are not to have any permanently connected lighting fixtures that are not a part of an appliance. The NEC(c) states special requirements for appliance branch circuits. We will go over a few of these requirements. In dwelling occupancies, small appliance loads, including refrigeration equipment, dining areas, kitchens, family rooms, pantries, and breakfast rooms, should have two or more 20-ampere branch circuits installed (referred to as special-purpose outlets) in addition to the branch circuits previously mentioned. These circuits will have no other outlets except for clock outlets.

At least two appliance receptacle branch circuits will be installed in the kitchen for receptacle outlets. In the laundry room at least one 20-ampere branch circuit will be provided. Again, always refer to the NEC(c) before installing any circuit or equipment to ensure you have the proper number of circuits needed and the correct size wiring and disconnecting means necessary for each branch circuit, appliance, and piece of equipment that you are to install,