1. Principles & Applications Residential Wiring Concepts
Electricity
Principles & Applications
Sixth Edition
Richard J. Fowler
Chapter 16
Residential Wiring Concepts
© Glencoe/McGraw-Hill

2. INTRODUCTION Equipment-grounding Conductor
Ground-Fault Circuit Interrupter
Arc-Fault Circuit Interrupter
Three-Way Lighting Circuit
Four-Way Lighting Circuit
Lighted-Handle Switches
Low-Voltage Control Circuit

3. Facts about Residential Wiring
A residence uses a 120-V/240-V single-phase system.
Hot conductors are 120 V with respect to neutral.
Hot conductors are 240 V with respect to each other.
Neutral conductors are either white or neutral gray.

4. More Facts About Residential Wiring
White conductors may be used as hot conductors.
An AFCI reduces the risk of electrical fires.
A GFCI protects people from ground-fault currents.
Equipment-grounding conductors are never fused.

5. Equipment-Grounding Conductor
Short
7.0 A
0.0 A
Ungrounded table
Grounded floor
Motor
standard
receptacle
7.5 A
0.5 A
There is no circuit fault. The motor is operating normally.
The motor develops a partial short. The branch circuit breaker doesn’t trip.
The motor continues to operate with some ground-fault current.
No shock is received because the motor frame is grounded.

6. Equipment-Grounding Conductor
?.? A
Motor
Short
standard
receptacle
7.5 A
7.0 A
Ungrounded table
Grounded floor
0.5A
7.0 A
The partially shorted motor continues to run. It doesn’t trip the branch circuit breaker.
Then the equipment-grounding conductor develops a broken or corroded connection.
A severe, or fatal, shock is received because the motor frame is not grounded.

7. Ground-Fault-Circuit Interrupter
Short
Motor
GFCI
receptacle
7.0 A
0.0 A
Ungrounded table
Grounded floor
0.0 A
0.0 A
A faulty equipment-grounding conductor doesn’t trip the GFCI.
With no ground, a partial short in the motor doesn’t trip the GFCI either.
No severe shock is received because the GFCI trips at about 5 mA.

8. Arc-Fault-Circuit-Interrupter Circuit Breaker
Loose screw
OFF ON
Hot bus
Neutral bus
This circuit breaker will open when an arc occurs.
Click the mouse to try it.

9. Ground-Fault Quiz
Is an equipment-grounding conductor ever fused or switched? No
Is a green conductor ever used for a neutral conductor? No
Can a neutral-gray conductor be used for a neutral conductor?
Yes
Will a ground-fault current greater than 10 mA trip a circuit breaker? No
Will a ground-fault current greater than 10 mA trip a GFCI?
Yes
Will a load current of 25 A trip a GFCI receptacle rated at 20 A? No
Will a 10-A ground-fault current cause an AFCI circuit breaker to trip? No

10. Wiring a Three-Way Lighting Circuit
fixture
14-3/G
14-2/G
Connect a hot conductor to the pole (dark-colored screw).
Ground the metal box.
Connect the throws together.
Continue the neutral and equipment-grounding conductors.
Connect a hot conductor to the remaining pole.
Again continue the neutral and equipment-grounding conductors.
Finally, connect the light fixture to the appropriate conductors.

11. A Four-Way Lighting Circuit
The circuit is in the off position. Equipment grounding is not shown.
Flipping the 4-way switch turns the circuit on.
Flipping either 3-way switch turns the light back off.
Flipping the 4-way switch again turns the circuit back on.
Flipping the other 3-way switch turns the circuit off again.
In summary, flipping any switch at any time will reverse the condition of the circuit.

12. Lighted-Handle Switch
120-V
lamp
When the light is off (switch open), the switch handle is lit.
When the light is on (switch closed), the switch handle is not lit.

13. Lighted-Handle 3-Way SwitchesB1 B2 H R1 R2 N
The light is on and the handles are not lit.
When either switch is toggled, the light goes out and both handles are lit.

14. Low-Voltage-Controlled Light Circuit
supply
Click the mouse and watch.
A switch is rocked to off.
The relay opens.
The light goes out.
And, the switch returns to its open position.
Another switch is rocked to off.
Nothing happens.
Again, the switch returns to its open position.
Now, a switch is rocked on.
The relay closes.
The light goes on.
Again, the switch returns to its open position.

15. Switching-Circuit Quiz
A 3-way lighting circuit requires _____
insulated conductors between switches.
three
A 4-way lighting circuit requires _____
insulated conductors between switches.
three
A _____ colored conductor should not
be used in the return leg of a switch.
white
A 4-way lighting circuit provides
control of a light from _____ locations.
three
The handle of a lighted-handle 3-way
switch is lit when the light is _____ .
off
A three-terminal relay stays in the on
position until the _____ is pulsed.
off coil

16. REVIEW Equipment-Grounding Conductor Ground-Fault Circuit Interrupter
Arc-Fault Circuit Interrupter
Three-Way Lighting Circuit
Four-Way Lighting Circuit
Lighted-Handle Switches
Low-Voltage Control Circuit