IAEI RESIDENTIAL ELECTRICAL INSPECTOR EXAM PRACTICE QUESTIONS
& CORRECT ANSWERS (VERIFIED ANSWERS) WITH DETAILED
RATIONALES LATEST UPDATE
SECTION 1: GENERAL REQUIREMENTS, SERVICES & FEEDER CALCULATIONS (Q1–30)
1. What is the minimum size copper grounding electrode conductor for a 200-
ampere
residential service?
a) 6 AWG
b) 4 AWG
c) 2 AWG
d) 1/0 AWG
Answer: c) 2 AWG
Rationale: According to NEC Table 250.66, a 200-amp service requires a minimum
2 AWG copper grounding electrode conductor.
2. Which type of receptacle is required in a bathroom?
a) Standard 15A
b) GFCI-protected
c) AFCI-protected
d) Tamper-resistant only
Answer: b) GFCI-protected
Rationale: NEC 210.8(A)(1) requires all 125V, 15A and 20A receptacles installed
in bathrooms to have GFCI protection.
3. What is the minimum number of 20-ampere small-appliance branch circuits
required for a dwelling unit kitchen?
a) One
b) Two
c) Three
d) Four
1
, Answer: b) Two
Rationale: NEC 210.11(C)(1) requires at least two 20A small-appliance branch
circuits to supply kitchen countertop receptacles.
4. The maximum total load on a 120V, 15A branch circuit in a residential dwelling
is:
a) 1200 VA
b) 1440 VA
c) 1800 VA
d) 1920 VA
Answer: c) 1800 VA
Rationale: 15A x 120V = 1800 VA. For continuous loads, derate to 80%, but
general residential circuits are not all continuous; the maximum rating is the
full 1800 VA.
5. What is the minimum clearance for overhead service conductors above a
residential
driveway?
a) 10 ft
b) 12 ft
c) 15 ft
d) 18 ft
Answer: b) 12 ft
Rationale: NEC 230.24(B) requires a minimum vertical clearance of 12 ft over
residential driveways and other areas subject to vehicle traffic.
6. Which section of the NEC defines a "dwelling unit"?
a) Article 100
b) Article 210
c) Article 220
2
, d) Article 310
Answer: a) Article 100
Rationale: Article 100 (Definitions) defines a dwelling unit as a single unit
providing complete independent living facilities.
7. For a one-family dwelling, the standard method of load calculation requires
a general lighting load of how many VA per square foot?
a) 2 VA
b) 3 VA
c) 5 VA
d) 8 VA
Answer: b) 3 VA
Rationale: NEC Table 220.12 requires 3 VA per square foot for dwelling unit
general lighting.
8. When applying demand factors to a dwelling unit's general lighting load,
what is the demand factor for the first 3000 VA?
a) 100%
b) 75%
c) 50%
d) 35%
Answer: a) 100%
Rationale: NEC Table 220.42 allows a 100% demand factor for the first 3000 VA
of general lighting in a dwelling.
9. A 240V electric range rated 12 kW in a dwelling has a minimum branch-circuit
rating of:
a) 30 A
b) 40 A
c) 50 A
3
, d) 60 A
Answer: b) 40 A
Rationale: NEC Table 220.55 permits a demand of 8 kW for a 12 kW range, and
NEC 210.19(A)(3) requires branch-circuit rating not less than the calculated
load. 8,000W / 240V = 33.3A → next standard size is 40A.
10. What is the maximum number of disconnecting means permitted for a
residential
service?
a) One
b) Two
c) Three
d) Six
Answer: d) Six
Rationale: NEC 230.71(A) permits up to six switches or circuit breakers as
the service disconnecting means.
11. The service disconnecting means for a dwelling must be installed at a readily
accessible location, either outside or:
a) Inside the garage
b) Inside the basement
c) Inside nearest the point of entrance
d) Under the stairs
Answer: c) Inside nearest the point of entrance
Rationale: NEC 230.70(A)(1) requires that if indoors, the service disconnect
be installed nearest the point of entry of the service conductors.
12. What is the minimum size aluminum grounding electrode conductor for a
100A
residential service?
4
& CORRECT ANSWERS (VERIFIED ANSWERS) WITH DETAILED
RATIONALES LATEST UPDATE
SECTION 1: GENERAL REQUIREMENTS, SERVICES & FEEDER CALCULATIONS (Q1–30)
1. What is the minimum size copper grounding electrode conductor for a 200-
ampere
residential service?
a) 6 AWG
b) 4 AWG
c) 2 AWG
d) 1/0 AWG
Answer: c) 2 AWG
Rationale: According to NEC Table 250.66, a 200-amp service requires a minimum
2 AWG copper grounding electrode conductor.
2. Which type of receptacle is required in a bathroom?
a) Standard 15A
b) GFCI-protected
c) AFCI-protected
d) Tamper-resistant only
Answer: b) GFCI-protected
Rationale: NEC 210.8(A)(1) requires all 125V, 15A and 20A receptacles installed
in bathrooms to have GFCI protection.
3. What is the minimum number of 20-ampere small-appliance branch circuits
required for a dwelling unit kitchen?
a) One
b) Two
c) Three
d) Four
1
, Answer: b) Two
Rationale: NEC 210.11(C)(1) requires at least two 20A small-appliance branch
circuits to supply kitchen countertop receptacles.
4. The maximum total load on a 120V, 15A branch circuit in a residential dwelling
is:
a) 1200 VA
b) 1440 VA
c) 1800 VA
d) 1920 VA
Answer: c) 1800 VA
Rationale: 15A x 120V = 1800 VA. For continuous loads, derate to 80%, but
general residential circuits are not all continuous; the maximum rating is the
full 1800 VA.
5. What is the minimum clearance for overhead service conductors above a
residential
driveway?
a) 10 ft
b) 12 ft
c) 15 ft
d) 18 ft
Answer: b) 12 ft
Rationale: NEC 230.24(B) requires a minimum vertical clearance of 12 ft over
residential driveways and other areas subject to vehicle traffic.
6. Which section of the NEC defines a "dwelling unit"?
a) Article 100
b) Article 210
c) Article 220
2
, d) Article 310
Answer: a) Article 100
Rationale: Article 100 (Definitions) defines a dwelling unit as a single unit
providing complete independent living facilities.
7. For a one-family dwelling, the standard method of load calculation requires
a general lighting load of how many VA per square foot?
a) 2 VA
b) 3 VA
c) 5 VA
d) 8 VA
Answer: b) 3 VA
Rationale: NEC Table 220.12 requires 3 VA per square foot for dwelling unit
general lighting.
8. When applying demand factors to a dwelling unit's general lighting load,
what is the demand factor for the first 3000 VA?
a) 100%
b) 75%
c) 50%
d) 35%
Answer: a) 100%
Rationale: NEC Table 220.42 allows a 100% demand factor for the first 3000 VA
of general lighting in a dwelling.
9. A 240V electric range rated 12 kW in a dwelling has a minimum branch-circuit
rating of:
a) 30 A
b) 40 A
c) 50 A
3
, d) 60 A
Answer: b) 40 A
Rationale: NEC Table 220.55 permits a demand of 8 kW for a 12 kW range, and
NEC 210.19(A)(3) requires branch-circuit rating not less than the calculated
load. 8,000W / 240V = 33.3A → next standard size is 40A.
10. What is the maximum number of disconnecting means permitted for a
residential
service?
a) One
b) Two
c) Three
d) Six
Answer: d) Six
Rationale: NEC 230.71(A) permits up to six switches or circuit breakers as
the service disconnecting means.
11. The service disconnecting means for a dwelling must be installed at a readily
accessible location, either outside or:
a) Inside the garage
b) Inside the basement
c) Inside nearest the point of entrance
d) Under the stairs
Answer: c) Inside nearest the point of entrance
Rationale: NEC 230.70(A)(1) requires that if indoors, the service disconnect
be installed nearest the point of entry of the service conductors.
12. What is the minimum size aluminum grounding electrode conductor for a
100A
residential service?
4
