1. Chapter Six
Ground-Fault Circuit Interrupters, Arc-Fault Circuit Interrupters, Surge Protective Devices, Immersion Detection Circuit Interrupters, and Appliance Leakage Current Interrupters

2. Objectives After studying this chapter, you should be able to:
Understand how GFCIs, AFCIs, IDCIs, and ALCIs operate
Understand NEC® requirements of where and how GFCIs and AFCIs are to be installed and connected
Understand why AFCIs and GFCIs should not be used on a shared neutral branch circuit unless it is listed as such

3. Objectives (cont’d.)
Select and install other special purpose devices including tamper-resistant and weather-resistant receptacles
Understand the important NEC® requirements for replacing existing receptacles
Know the rules for providing GFCI protection on construction sites
Understand the basics of surge protective devices

4. Electrical Shock Hazards
There can be no compromise where human life is involved!
If equipment is not properly grounded, the potential for an electrical shock is present
The shock hazard exists whenever the user can touch both the defective equipment and grounded surfaces

5. Electric Shock Hazards (cont’d.)
Electrical shock can cause internal damage
The effect of current passing through the body depends on:
Circuit characteristics
Body resistance
Contact duration
Path
Humidity

6. Electric Shock Hazards (cont’d.)
The resistance (ohms) of the human body varies from a few hundred ohms to many thousand ohms
Generally, voltages less than 50 volts are safe
Voltages 50 volts and greater are considered lethal

7. FIGURE 6-1 The time/current curve shows the tripping characteristics of a typical Class A GFCI. Note that if you follow the 6-mA line vertically to the crosshatched typical time/current curve, you will find that the GFCI will open in from approximately second to just less than 0.1 second. One electrical cycle is 1/60 of a second ( second). An air bag in an automobile inflates in approximately 1/20 of a second (0.05 second). © Cengage Learning 2015 14

8. Electric Shock Hazards (cont’d.)
AC systems from 50 to 1000 volts are required to be grounded
A grounded system enhances safety

9. Code Requirements for Ground-Fault Circuit Interrupters (210.8)
There are many receptacle locations that are required to be GFCI protected
Receptacles located near water must be GFCI protected

10. FIGURE 6-5 Ground-fault circuit interrupter as part of the feeder supplying a panel that serves a number of 15- and 20-ampere branch circuits. This is permitted by NEC® but is rarely—if ever—used in residential wiring. © Cengage Learning 2015 14

11. Ground-Fault Circuit Interrupters in Residence Circuits
GFCI protection is not required for a receptacle for a fire alarm or burglar alarm system
GFCI breakers protect the entire circuit

12. Feed-Through Ground-Fault Circuit Interrupter
Most GFCI receptacles on the market today have the “feed-through” feature
GFCI receptacles can be wired to protect “downstream” receptacles
All GFCI receptacles have a manual TEST button and a RESET button

13. Testing and Recording of Test Data for GFCI Receptacles
GFCIs should be tested often
Particularly in high lightning strike areas
Self-testing GRCIs are available
UL requires detailed installation and testing instructions in GFCI packaging

14. Arc-Fault Circuit Interrupters (AFCIs)
AFCI devices are relatively new
There are circuit-breaker and receptacle type AFCIs
AFCI and GFCI protect against different types of electrical hazards

15. Testing and Recording of Test Data for GFCI Receptacles (cont’d.)
AFCI protection is required in dwelling unit
Kitchens
Family rooms
Dining rooms
Living rooms
Parlors
Libraries
Dens
Bedrooms
Sun rooms
Recreation rooms
Closets
Hallways
Laundry areas
Similar rooms or areas

16. Other Special Purpose Receptacles
Tamper-resistant receptacles
A major step to reduce the number of injuries
Small children especially insert “things” into slots
Weather resistant: installed in damp locations

17. Replacing Existing Receptacles
NEC is very specific on the type of receptacle permitted to be used for replacements
Code rules are found in 406.4(D)
Replacing existing two-wire receptacles
Where grounding means exists
Where grounding means does not exist

18. FIGURE 6-22 Where a grounding means does not exist, there are certain marking requirements as presented in this diagram. Do not connect an equipment grounding conductor between these receptacles; see 406.3(D)(2).
© Cengage Learning 2015 14

19. Personnel Ground-Fault Protection for All Temporary Wiring
Because of the nature of construction sites, there is a continual presence of shock hazard
Most electricians and other construction site workers carry their own listed portable ground-fault circuit-interrupter cord sets

20. IDCIs and ALCIs
The large attachment plug cap on hand-held grooming appliances such as hair dryers, combs, and curlers is an IDCI or ALCI
If the appliance is dropped into water or gets wet, the IDCI or ALCI will safely de-energize the appliance

21. FIGURE 6-26 An example of a temporary construction site combination meter, breakers, and receptacles. The breakers and receptacles are under the lift-up cover.
© Cengage Learning 2015 18

22. Surge Protective Devices (SPD)
Code requirements found in Article 285
Ring wave: originate within the building and can be caused by such things as copiers, computers, and printers
Impulse: these transients originate outside of the building and are caused by utility company switching, lightning, and so on