Engineering Fundamentals: An Introduction to Engineering, 4th ed.c

352 Chapter 12 Electric Current and Related Parameters

4 GCFI

Pool outlets

Basement lighting and outlets

First floor lighting

Living/family room

Bathroom lighting and outlets

Bedroom outlets

Kitchen appliances

Kitchen appliances

Kitchen outlets

Kitchen lighting

Garage outlets

Furnace

Shop equipment

Utility room

Utility room

Oven-range

Dishwasher

Sink disposal unit

Water heater

Central air

conditioner

20 A

15 A

15 A

15 A

15 A

15 A

15 A

20 A

20 A

20 A

20 A

20 A

20 A

20 A

30 A

50 A

50 A

20 A

15 A

20 A

GFCI

Conduit

to meter

Meter

Service cable

to house

200-amp main

circuit breaker

Circuit breaker

and distribution

panel

■Figure 12.7 An example of an electrical distribution system for a residential building.

Source:From Electrical Wiring, Second Edition, 1981, p18, Copyright © 1981 AAVIM. Reprinted by permission.

Residential Power Distribution

An example of a typical residential power distribution system is shown in Figure 12.7,

which gives examples of amperage requirements for outlets, lights, kitchen appliances, and

central air conditioning. To wire a building, an electrical plan for the building must first be

developed. In the plan, the location and the types of switches and outlets, including outlets

for the range and dryer, must be specified. We will discuss engineering symbols in more detail

in Chapter 16. For now, examples of electrical symbols used in a house plan are shown in

Figure 12.8. Moreover, an example of an electrical plan for a residential building is shown

in Figure 12.9.

12.4 Electrical Circuits and Components

Anelectrical circuitrefers to the combination of various electrical components that are

connected together. Examples of electrical components include wires (conductors), switches,

outlets, resistors, and capacitors. First, let us take a closer look at electrical wires. In a wire the

resistance to electrical current depends on the material from which the wire is made and its

length, diameter, and temperature. Materials show varying amount of resistance to the flow of

electric current.Resistivityis a measure of resistance of a piece of material to electric current.

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