1.
A service disconnect is required to have a minimum rating based on calculated load. What is the minimum
rating permitted for a one-family dwelling service disconnect?
A. 60 A
B. 100 A
C. 100 A
D. 125 A
Rationale: NEC requires a minimum 100-amp service disconnect for one-family dwellings (NEC 230.79(C)).
2.
What is the minimum burial depth for rigid metal conduit (RMC) under a residential driveway?
A. 6 inches
B. 12 inches
C. 18 inches
D. 24 inches
Rationale: NEC Table 300.5 specifies 18 inches for RMC under driveways.
3.
Which conductor type is permitted for use in wet locations?
A. NM
B. THHN
C. THWN-2
D. UF-B only
Rationale: Only conductors rated for wet locations like THWN-2 are permitted (NEC 310.10).
4.
What is the maximum number of disconnects allowed for a service?
A. 4
B. 5
,C. 6
D. 8
Rationale: NEC 230.71 allows up to six disconnects.
5.
What is the required working space depth for equipment rated 0–150V to ground?
A. 2 ft
B. 3 ft
C. 4 ft
D. 5 ft
Rationale: NEC 110.26 requires 3 feet minimum depth.
6.
A feeder supplies a continuous load of 80A. What minimum conductor ampacity is required?
A. 80A
B. 90A
C. 100A
D. 125A
Rationale: Continuous loads require 125% sizing → 80 × 1.25 = 100A.
7.
Which wiring method is prohibited in plenums?
A. EMT
B. RMC
C. NM cable
D. MC cable
Rationale: NM cable is not plenum-rated (NEC 300.22).
8.
What is the minimum height for service drop conductors over a residential driveway?
A. 10 ft
B. 12 ft
C. 12 ft
D. 15 ft
Rationale: NEC 230.24 requires 12 ft minimum.
, 9.
What is the maximum overcurrent protection allowed for #14 copper conductors?
A. 15 A
B. 20 A
C. 25 A
D. 30 A
Rationale: NEC 240.4(D) limits #14 copper to 15A.
10.
Where is GFCI protection required?
A. Bedrooms
B. Living rooms
C. Bathrooms
D. Closets
Rationale: Bathrooms require GFCI protection (NEC 210.8).
11.
What is the minimum cover for direct burial cable under a sidewalk?
A. 12 inches
B. 18 inches
C. 24 inches
D. 30 inches
Rationale: NEC Table 300.5 → 18 inches.
12.
What type of receptacle is required for hospital-grade installations?
A. Standard duplex
B. Tamper-resistant
C. Hospital-grade listed
D. AFCI type
Rationale: Must be listed hospital-grade (NEC 517).
13.
A service disconnect is required to have a minimum rating based on calculated load. What is the minimum
rating permitted for a one-family dwelling service disconnect?
A. 60 A
B. 100 A
C. 100 A
D. 125 A
Rationale: NEC requires a minimum 100-amp service disconnect for one-family dwellings (NEC 230.79(C)).
2.
What is the minimum burial depth for rigid metal conduit (RMC) under a residential driveway?
A. 6 inches
B. 12 inches
C. 18 inches
D. 24 inches
Rationale: NEC Table 300.5 specifies 18 inches for RMC under driveways.
3.
Which conductor type is permitted for use in wet locations?
A. NM
B. THHN
C. THWN-2
D. UF-B only
Rationale: Only conductors rated for wet locations like THWN-2 are permitted (NEC 310.10).
4.
What is the maximum number of disconnects allowed for a service?
A. 4
B. 5
,C. 6
D. 8
Rationale: NEC 230.71 allows up to six disconnects.
5.
What is the required working space depth for equipment rated 0–150V to ground?
A. 2 ft
B. 3 ft
C. 4 ft
D. 5 ft
Rationale: NEC 110.26 requires 3 feet minimum depth.
6.
A feeder supplies a continuous load of 80A. What minimum conductor ampacity is required?
A. 80A
B. 90A
C. 100A
D. 125A
Rationale: Continuous loads require 125% sizing → 80 × 1.25 = 100A.
7.
Which wiring method is prohibited in plenums?
A. EMT
B. RMC
C. NM cable
D. MC cable
Rationale: NM cable is not plenum-rated (NEC 300.22).
8.
What is the minimum height for service drop conductors over a residential driveway?
A. 10 ft
B. 12 ft
C. 12 ft
D. 15 ft
Rationale: NEC 230.24 requires 12 ft minimum.
, 9.
What is the maximum overcurrent protection allowed for #14 copper conductors?
A. 15 A
B. 20 A
C. 25 A
D. 30 A
Rationale: NEC 240.4(D) limits #14 copper to 15A.
10.
Where is GFCI protection required?
A. Bedrooms
B. Living rooms
C. Bathrooms
D. Closets
Rationale: Bathrooms require GFCI protection (NEC 210.8).
11.
What is the minimum cover for direct burial cable under a sidewalk?
A. 12 inches
B. 18 inches
C. 24 inches
D. 30 inches
Rationale: NEC Table 300.5 → 18 inches.
12.
What type of receptacle is required for hospital-grade installations?
A. Standard duplex
B. Tamper-resistant
C. Hospital-grade listed
D. AFCI type
Rationale: Must be listed hospital-grade (NEC 517).
13.
