CO CLASS E ELECTRICAL CONTRACTOR EXAM
QUESTIONS AND CORRECT ANSWERS (VERIFIED
ANSWERS) Q&A 2027 |INSTANT DOWNLOAD PDF
1. What is the primary purpose of the National Electrical
Code (NEC)?
A. To establish electrical utility rates
B. To provide practical safeguards for persons and
property from electrical hazards
C. To regulate electrician wages
D. To determine contractor insurance premiums
Rationale: The NEC establishes minimum safety
requirements for electrical installations.
Correct Answer: B. To provide practical safeguards for
persons and property from electrical hazards
2. Which unit is used to measure electrical current?
A. Volt
B. Ohm
C. Ampere
D. Watt
Rationale: Current is measured in amperes, commonly
called amps.
Correct Answer: C. Ampere
3. Which unit measures electrical resistance?
A. Ohm
, B. Volt
C. Ampere
D. Watt
Rationale: The ohm is the standard unit of electrical
resistance.
Correct Answer: A. Ohm
4. Which formula represents Ohm's Law?
A. P = I/R
B. V = I × R
C. R = V × I
D. I = V × R
Rationale: Ohm's Law states that voltage equals current
multiplied by resistance.
Correct Answer: B. V = I × R
5. What is the purpose of an overcurrent protective device?
A. Increase voltage
B. Reduce electrical resistance
C. Protect conductors and equipment from excessive
current
D. Increase circuit frequency
Rationale: Fuses and circuit breakers protect circuits
against excessive current.
Correct Answer: C. Protect conductors and equipment from
excessive current
6. Which device is designed to open a circuit automatically
when excessive current occurs?
, A. Transformer
B. Circuit breaker
C. Receptacle
D. Switchboard
Rationale: Circuit breakers automatically interrupt current
when an overcurrent condition occurs.
Correct Answer: B. Circuit breaker
7. What does GFCI stand for?
A. Ground Fault Circuit Interrupter
B. General Fuse Circuit Indicator
C. Ground Frequency Current Instrument
D. General Fault Control Interface
Rationale: GFCI devices detect current leakage and
interrupt power under specified conditions.
Correct Answer: A. Ground Fault Circuit Interrupter
8. What is the main purpose of a GFCI?
A. Protect against electric shock from ground faults
B. Increase circuit voltage
C. Prevent all overloads
D. Improve power factor
Rationale: GFCI protection is primarily intended to reduce
shock hazards caused by ground-fault current.
Correct Answer: A. Protect against electric shock from
ground faults
9. What is the purpose of an equipment grounding
conductor?
, A. Carry normal load current
B. Provide a low-impedance path for fault current
C. Increase voltage
D. Reduce conductor size
Rationale: The equipment grounding conductor provides a
path for fault current so the protective device can operate.
Correct Answer: B. Provide a low-impedance path for fault
current
10. Which conductor normally carries current in a
grounded AC circuit?
A. Grounding electrode conductor
B. Equipment grounding conductor
C. Grounded conductor
D. Bonding jumper only
Rationale: The grounded conductor, commonly called the
neutral in many systems, normally carries return current.
Correct Answer: C. Grounded conductor
11. What is the primary function of bonding?
A. Increase resistance
B. Establish electrical continuity between conductive parts
C. Increase voltage
D. Eliminate the need for overcurrent protection
Rationale: Bonding connects conductive parts so they
remain at substantially the same electrical potential and
provide a fault-current path where required.
QUESTIONS AND CORRECT ANSWERS (VERIFIED
ANSWERS) Q&A 2027 |INSTANT DOWNLOAD PDF
1. What is the primary purpose of the National Electrical
Code (NEC)?
A. To establish electrical utility rates
B. To provide practical safeguards for persons and
property from electrical hazards
C. To regulate electrician wages
D. To determine contractor insurance premiums
Rationale: The NEC establishes minimum safety
requirements for electrical installations.
Correct Answer: B. To provide practical safeguards for
persons and property from electrical hazards
2. Which unit is used to measure electrical current?
A. Volt
B. Ohm
C. Ampere
D. Watt
Rationale: Current is measured in amperes, commonly
called amps.
Correct Answer: C. Ampere
3. Which unit measures electrical resistance?
A. Ohm
, B. Volt
C. Ampere
D. Watt
Rationale: The ohm is the standard unit of electrical
resistance.
Correct Answer: A. Ohm
4. Which formula represents Ohm's Law?
A. P = I/R
B. V = I × R
C. R = V × I
D. I = V × R
Rationale: Ohm's Law states that voltage equals current
multiplied by resistance.
Correct Answer: B. V = I × R
5. What is the purpose of an overcurrent protective device?
A. Increase voltage
B. Reduce electrical resistance
C. Protect conductors and equipment from excessive
current
D. Increase circuit frequency
Rationale: Fuses and circuit breakers protect circuits
against excessive current.
Correct Answer: C. Protect conductors and equipment from
excessive current
6. Which device is designed to open a circuit automatically
when excessive current occurs?
, A. Transformer
B. Circuit breaker
C. Receptacle
D. Switchboard
Rationale: Circuit breakers automatically interrupt current
when an overcurrent condition occurs.
Correct Answer: B. Circuit breaker
7. What does GFCI stand for?
A. Ground Fault Circuit Interrupter
B. General Fuse Circuit Indicator
C. Ground Frequency Current Instrument
D. General Fault Control Interface
Rationale: GFCI devices detect current leakage and
interrupt power under specified conditions.
Correct Answer: A. Ground Fault Circuit Interrupter
8. What is the main purpose of a GFCI?
A. Protect against electric shock from ground faults
B. Increase circuit voltage
C. Prevent all overloads
D. Improve power factor
Rationale: GFCI protection is primarily intended to reduce
shock hazards caused by ground-fault current.
Correct Answer: A. Protect against electric shock from
ground faults
9. What is the purpose of an equipment grounding
conductor?
, A. Carry normal load current
B. Provide a low-impedance path for fault current
C. Increase voltage
D. Reduce conductor size
Rationale: The equipment grounding conductor provides a
path for fault current so the protective device can operate.
Correct Answer: B. Provide a low-impedance path for fault
current
10. Which conductor normally carries current in a
grounded AC circuit?
A. Grounding electrode conductor
B. Equipment grounding conductor
C. Grounded conductor
D. Bonding jumper only
Rationale: The grounded conductor, commonly called the
neutral in many systems, normally carries return current.
Correct Answer: C. Grounded conductor
11. What is the primary function of bonding?
A. Increase resistance
B. Establish electrical continuity between conductive parts
C. Increase voltage
D. Eliminate the need for overcurrent protection
Rationale: Bonding connects conductive parts so they
remain at substantially the same electrical potential and
provide a fault-current path where required.
