Idaho Master Electrician Exam
Questions And Correct Answers
(Verified Answers) Plus Rationales 2026
Q&A | Instant Download Pdf
1. What is the maximum overcurrent protection allowed for a 12 AWG
copper conductor used for general lighting in a dwelling?
A. 15 amps
B. 20 amps
C. 25 amps
D. 30 amps
B. 20 amps
12 AWG copper conductors are rated for 20 amps according to the
NEC 310.15(B)(16).
2. What is the purpose of a grounding electrode conductor?
A. Carry normal current
B. Prevent overcurrent
C. Connect the system to earth
D. Protect against short circuits
C. Connect the system to earth
It provides a low-impedance path to dissipate fault currents safely
into the earth.
3. In a 120/240V single-phase dwelling service, what is the voltage
between the two ungrounded conductors?
A. 120V
B. 208V
C. 240V
, D. 480V
C. 240V
The two hot legs in a split-phase system provide 240 volts across
them.
4. Which conductor color is typically used for the neutral in AC wiring?
A. Black
B. White
C. Red
D. Green
B. White
NEC requires the grounded conductor (neutral) to be white or gray.
5. What is the minimum size copper equipment grounding conductor for
a 60-ampere circuit?
A. 14 AWG
B. 12 AWG
C. 10 AWG
D. 8 AWG
C. 10 AWG
According to NEC Table 250.122, a 60-amp circuit requires a 10 AWG
copper grounding conductor.
6. What type of wiring method is commonly used for residential branch
circuits?
A. EMT
B. RMC
C. NM cable
D. MC cable
C. NM cable
Nonmetallic-sheathed (NM) cable, commonly known as Romex, is
widely used in residential wiring.
7. What is the maximum number of 12 AWG conductors allowed in a
standard 20-ampere residential electrical box with a volume of 18
, cubic inches?
A. 3
B. 4
C. 5
D. 6
C. 5
NEC Chapter 314 allows 2 conductors per 18 cubic inch box plus 1 for
the device and 1 for ground; 12 AWG counts as one unit per
conductor.
8. Which NEC article covers grounding and bonding requirements?
A. Article 210
B. Article 250
C. Article 300
D. Article 310
B. Article 250
NEC Article 250 addresses grounding and bonding of electrical
systems and equipment.
9. What is the maximum number of disconnects allowed in a single
service disconnecting means for a single-family dwelling?
A. 1
B. 2
C. 3
D. 6
D. 6
NEC 230.71(A) allows up to six disconnects in a single service for a
one-family dwelling.
10. What is the ampacity of a 6 AWG copper conductor in a raceway
at 30°C ambient temperature?
A. 40 amps
B. 55 amps
C. 65 amps
Questions And Correct Answers
(Verified Answers) Plus Rationales 2026
Q&A | Instant Download Pdf
1. What is the maximum overcurrent protection allowed for a 12 AWG
copper conductor used for general lighting in a dwelling?
A. 15 amps
B. 20 amps
C. 25 amps
D. 30 amps
B. 20 amps
12 AWG copper conductors are rated for 20 amps according to the
NEC 310.15(B)(16).
2. What is the purpose of a grounding electrode conductor?
A. Carry normal current
B. Prevent overcurrent
C. Connect the system to earth
D. Protect against short circuits
C. Connect the system to earth
It provides a low-impedance path to dissipate fault currents safely
into the earth.
3. In a 120/240V single-phase dwelling service, what is the voltage
between the two ungrounded conductors?
A. 120V
B. 208V
C. 240V
, D. 480V
C. 240V
The two hot legs in a split-phase system provide 240 volts across
them.
4. Which conductor color is typically used for the neutral in AC wiring?
A. Black
B. White
C. Red
D. Green
B. White
NEC requires the grounded conductor (neutral) to be white or gray.
5. What is the minimum size copper equipment grounding conductor for
a 60-ampere circuit?
A. 14 AWG
B. 12 AWG
C. 10 AWG
D. 8 AWG
C. 10 AWG
According to NEC Table 250.122, a 60-amp circuit requires a 10 AWG
copper grounding conductor.
6. What type of wiring method is commonly used for residential branch
circuits?
A. EMT
B. RMC
C. NM cable
D. MC cable
C. NM cable
Nonmetallic-sheathed (NM) cable, commonly known as Romex, is
widely used in residential wiring.
7. What is the maximum number of 12 AWG conductors allowed in a
standard 20-ampere residential electrical box with a volume of 18
, cubic inches?
A. 3
B. 4
C. 5
D. 6
C. 5
NEC Chapter 314 allows 2 conductors per 18 cubic inch box plus 1 for
the device and 1 for ground; 12 AWG counts as one unit per
conductor.
8. Which NEC article covers grounding and bonding requirements?
A. Article 210
B. Article 250
C. Article 300
D. Article 310
B. Article 250
NEC Article 250 addresses grounding and bonding of electrical
systems and equipment.
9. What is the maximum number of disconnects allowed in a single
service disconnecting means for a single-family dwelling?
A. 1
B. 2
C. 3
D. 6
D. 6
NEC 230.71(A) allows up to six disconnects in a single service for a
one-family dwelling.
10. What is the ampacity of a 6 AWG copper conductor in a raceway
at 30°C ambient temperature?
A. 40 amps
B. 55 amps
C. 65 amps
