Michigan Electrical Code Exam
Questions and Correct Answers
(Verified Answers) Plus Rationales 2026
Q&A | Instant Download Pdf
Electrical Theory, General Knowledge, Grounding & Bonding, Overcurrent
Protection, Wiring Methods, and Services
1. Which formula expresses Ohm's Law for calculating current?
A. I = E × R
B. I = R ÷ E
C. I = E ÷ R
D. I = E + R
Answer: C. I = E ÷ R
Rationale: Ohm's Law states that current equals voltage divided by resistance.
Therefore, when voltage and resistance are known, current can be calculated
using I = E/R.
2. A 120-volt load has a resistance of 24 ohms. What current does the load
draw?
A. 5 amperes
B. 2 amperes
C. 24 amperes
D. 120 amperes
Answer: A. 5 amperes
Rationale: Using Ohm's Law, I = E/R = 120/24 = 5 amperes. The load therefore
draws 5 A under the stated conditions.
,3. What is the primary purpose of an equipment grounding conductor?
A. Carry normal load current continuously
B. Provide a low-impedance path for fault current
C. Increase the operating voltage of a circuit
D. Replace the grounded circuit conductor
Answer: B. Provide a low-impedance path for fault current
Rationale: The equipment grounding conductor provides a conductive path
intended to facilitate operation of the overcurrent protective device when a
ground fault occurs.
4. At a service, what is the primary function of the main bonding jumper?
A. Increase the ampacity of the service conductors
B. Protect branch-circuit conductors from overload
C. Connect the grounding electrode to the utility transformer
D. Establish the connection between the grounded conductor and the equipment
grounding/bonding system at the service
Answer: D. Establish the connection between the grounded conductor and the
equipment grounding/bonding system at the service
Rationale: The main bonding jumper establishes the required connection between
the grounded service conductor and the equipment grounding and bonding
system at the service disconnecting means.
5. Which device is normally used to protect a circuit conductor from excessive
current caused by an overload or short circuit?
A. Overcurrent protective device
B. Transformer
C. Disconnect handle
D. Junction box
,Answer: A. Overcurrent protective device
Rationale: Fuses and circuit breakers are overcurrent protective devices designed
to open a circuit when excessive current reaches the applicable operating
conditions.
6. A circuit breaker is rated at 20 amperes. What is the primary purpose of that
rating?
A. It indicates the voltage supplied by the utility
B. It identifies the maximum number of receptacles permitted
C. It establishes the circuit breaker's current rating
D. It identifies the conductor insulation temperature
Answer: C. It establishes the circuit breaker's current rating
Rationale: The ampere rating of a circuit breaker identifies the current rating of
the device under its applicable conditions of use. Conductor sizing must also
comply with the applicable NEC requirements.
7. Which wiring method provides a raceway system consisting of electrical
metallic tubing?
A. EMT
B. NM cable
C. UF cable
D. Type SE cable
Answer: A. EMT
Rationale: Electrical metallic tubing, commonly abbreviated EMT, is a metallic
raceway recognized by the NEC for permitted wiring installations.
8. What is the primary purpose of a junction box?
A. Increase circuit voltage
B. Provide an enclosure for permitted conductor splices and connections
, C. Replace circuit overcurrent protection
D. Serve as a grounding electrode
Answer: B. Provide an enclosure for permitted conductor splices and
connections
Rationale: Junction and outlet boxes provide enclosed locations for electrical
connections, splices, and device installations as permitted by the applicable code
requirements.
9. Which condition generally requires a conductor to have insulation suitable for
the environment in which it is installed?
A. Only installations containing motors
B. Only installations above 600 volts
C. The conditions of the location and intended use
D. Only installations in residential buildings
Answer: C. The conditions of the location and intended use
Rationale: Conductor insulation must be suitable for the application, including
factors such as temperature, moisture, chemicals, sunlight, and other
environmental conditions where applicable.
10. What is the primary function of a service disconnecting means?
A. Provide a means to disconnect the building's service conductors from the
source of supply
B. Control the speed of every motor in the building
C. Increase the available fault current
D. Replace all branch-circuit overcurrent devices
Answer: A. Provide a means to disconnect the building's service conductors
from the source of supply
Rationale: The service disconnecting means provides a means of disconnecting the
service conductors and is subject to specific location, rating, grouping, and
accessibility requirements.
Questions and Correct Answers
(Verified Answers) Plus Rationales 2026
Q&A | Instant Download Pdf
Electrical Theory, General Knowledge, Grounding & Bonding, Overcurrent
Protection, Wiring Methods, and Services
1. Which formula expresses Ohm's Law for calculating current?
A. I = E × R
B. I = R ÷ E
C. I = E ÷ R
D. I = E + R
Answer: C. I = E ÷ R
Rationale: Ohm's Law states that current equals voltage divided by resistance.
Therefore, when voltage and resistance are known, current can be calculated
using I = E/R.
2. A 120-volt load has a resistance of 24 ohms. What current does the load
draw?
A. 5 amperes
B. 2 amperes
C. 24 amperes
D. 120 amperes
Answer: A. 5 amperes
Rationale: Using Ohm's Law, I = E/R = 120/24 = 5 amperes. The load therefore
draws 5 A under the stated conditions.
,3. What is the primary purpose of an equipment grounding conductor?
A. Carry normal load current continuously
B. Provide a low-impedance path for fault current
C. Increase the operating voltage of a circuit
D. Replace the grounded circuit conductor
Answer: B. Provide a low-impedance path for fault current
Rationale: The equipment grounding conductor provides a conductive path
intended to facilitate operation of the overcurrent protective device when a
ground fault occurs.
4. At a service, what is the primary function of the main bonding jumper?
A. Increase the ampacity of the service conductors
B. Protect branch-circuit conductors from overload
C. Connect the grounding electrode to the utility transformer
D. Establish the connection between the grounded conductor and the equipment
grounding/bonding system at the service
Answer: D. Establish the connection between the grounded conductor and the
equipment grounding/bonding system at the service
Rationale: The main bonding jumper establishes the required connection between
the grounded service conductor and the equipment grounding and bonding
system at the service disconnecting means.
5. Which device is normally used to protect a circuit conductor from excessive
current caused by an overload or short circuit?
A. Overcurrent protective device
B. Transformer
C. Disconnect handle
D. Junction box
,Answer: A. Overcurrent protective device
Rationale: Fuses and circuit breakers are overcurrent protective devices designed
to open a circuit when excessive current reaches the applicable operating
conditions.
6. A circuit breaker is rated at 20 amperes. What is the primary purpose of that
rating?
A. It indicates the voltage supplied by the utility
B. It identifies the maximum number of receptacles permitted
C. It establishes the circuit breaker's current rating
D. It identifies the conductor insulation temperature
Answer: C. It establishes the circuit breaker's current rating
Rationale: The ampere rating of a circuit breaker identifies the current rating of
the device under its applicable conditions of use. Conductor sizing must also
comply with the applicable NEC requirements.
7. Which wiring method provides a raceway system consisting of electrical
metallic tubing?
A. EMT
B. NM cable
C. UF cable
D. Type SE cable
Answer: A. EMT
Rationale: Electrical metallic tubing, commonly abbreviated EMT, is a metallic
raceway recognized by the NEC for permitted wiring installations.
8. What is the primary purpose of a junction box?
A. Increase circuit voltage
B. Provide an enclosure for permitted conductor splices and connections
, C. Replace circuit overcurrent protection
D. Serve as a grounding electrode
Answer: B. Provide an enclosure for permitted conductor splices and
connections
Rationale: Junction and outlet boxes provide enclosed locations for electrical
connections, splices, and device installations as permitted by the applicable code
requirements.
9. Which condition generally requires a conductor to have insulation suitable for
the environment in which it is installed?
A. Only installations containing motors
B. Only installations above 600 volts
C. The conditions of the location and intended use
D. Only installations in residential buildings
Answer: C. The conditions of the location and intended use
Rationale: Conductor insulation must be suitable for the application, including
factors such as temperature, moisture, chemicals, sunlight, and other
environmental conditions where applicable.
10. What is the primary function of a service disconnecting means?
A. Provide a means to disconnect the building's service conductors from the
source of supply
B. Control the speed of every motor in the building
C. Increase the available fault current
D. Replace all branch-circuit overcurrent devices
Answer: A. Provide a means to disconnect the building's service conductors
from the source of supply
Rationale: The service disconnecting means provides a means of disconnecting the
service conductors and is subject to specific location, rating, grouping, and
accessibility requirements.
