Chapter Eighteen – ELECTRICAL HAZARDS
TRUE OR FALSE: Place T or F in the space provided.
_____1. Grounding of electrical equipment is the primary method of reducing
electrical hazards.
_____2. The greatest danger to humans suffering electrical shock results from
current ow.
_____3. The path of ow of electrons is from a positive source to a negative
point.
_____4. To reduce the risk of electrocution by lightning, do not use electrical
equipment during storms.
_____5. Most industrial and domestic use of electricity is supplied by direct
current.
_____6. A continuity tester may be used to determine whether a conductor is
properly grounded or has a break in the circuit.
_____7. A circuit tester may be used to test 110-volt circuits only.
_____8. Television antenna towers do not require grounding.
_____9. The NEC speci1es industrial and domestic electrical safety
precautions.
_____10. An arc ash is an electrical short circuit that travels through the air.
_____11. Circuit breaker testing requirements are not contained in NFPA 70E.
_____12. A short circuit is one in which the load has been removed or
bypassed.
MULTIPLE CHOICE: Circle the letter before the correct answer.
1. Ohm’s law is stated as:
A. W=VI
B. V=IR
C. W=VR
D. I=RW
2. A tree is a common natural path for what type of electrical hazard?
A. Arc
B. Insulation failure
C. Lightning
D. Spark
3. Power is measured in:
A. Resistance
B. Amps
C. Ohms
D. Watts
4. In the US, standard AC circuits cycle how many times per second?
A. 60
B. 110
C. 220
D. 115
5. A safety device used to detect the ow of current to the ground and to
open the circuit is:
A. Circuit breaker
B. Fuse
C. Conductor
D. Ground fault interrupter
6. Which of the following is not included in NFPA 70E?
A. General maintenance requirements
B. Protective devices
C. Training requirements for electrical and electronic engineers
D. Fuses
12. T
6. C
1. De1ne zero potential. Explain the relationship between zero potential and
grounding.
2. Explain what each of the following terms measure: volt, amp, ohm, hertz,
and watt.
3. Briey discuss the difference between DC and AC using the concept of
effective current.
4. What is the relationship between the NEC and UL?
5. Briey state the relationship between potential difference, lightning, and
grounding.
6. De1ne open ground.
7. List at least 1ve lightning hazard control measures.
8. Explain the relationship between circuit load and short circuits.
9. How do ionizers, radioactive neutralizers, and antistatic materials work?
Why does humidi1cation work?
10. Discuss how bonding and grounding work together to increase electrical
safety.
11. How do continuity testers, circuit testers, and receptacle wiring testers
operate?
12. Explain freeze and let go current.
13. Describe the structure of an atom.
14. Discuss the proper wiring of a three-wire circuit.
15. Why is jumping the ground wire a hazard?
16. Explain reversed polarity.
17. Why are warning devices less effective than designed-in safety
precautions?
18. Explain 1ve strategies for establishing an effective electrical safety
program.
19. Explain why it is so important for safety personnel to help employees and
supervisors conduct self-assessments.
20. Explain how to reduce arc ash hazards.