IAEI Residential Electrical Inspector
Examination Prep: Practice Questions
with Verified Answers and NEC
Rationales
1. What is the minimum size copper grounding electrode conductor
required for a 200-ampere residential service?
o Answer: 2 AWG
o Rationale: The sizing of the grounding electrode conductor is
determined by the size of the largest service-entrance conductor, not
the overcurrent device rating alone. For a typical 200-ampere
residential service, NEC Table 250.66 requires a minimum 2 AWG
copper conductor for the connection to the grounding electrode .
2. Which type of receptacle is mandated for installation in a residential
bathroom?
o Answer: GFCI protected
o Rationale: NEC 210.8(A)(1) specifically requires ground-fault circuit-
interrupter (GFCI) protection for all 125-volt, 15- and 20-ampere
receptacles installed in bathrooms. This is a critical safety requirement
to prevent electrocution in areas with high moisture .
3. What is the maximum distance allowed between receptacles along a
wall in a living room?
o Answer: 12 feet
,o Rationale: The NEC (210.52(A)(1)) requires that no point along the
wall floor line is more than 6 feet from a receptacle. This ensures that
a lamp or appliance with a standard 6-foot cord can be plugged in
without crossing a doorway, resulting in a practical maximum spacing
of 12 feet between receptacles .
4. How many 20-ampere small appliance branch circuits are required to
serve the kitchen countertop receptacles in a dwelling?
o Answer: 2 or more
o Rationale: NEC 210.11(C)(1) mandates at least two 20-ampere small-
appliance branch circuits for the receptacles in the kitchen, pantry,
breakfast room, and similar dining areas. This ensures sufficient
capacity for high-wattage countertop appliances .
5. What is the standard color identification for a neutral conductor in
residential wiring?
o Answer: White or gray
o Rationale: NEC 200.6 requires that the grounded (neutral) conductor
be identified by a continuous white or gray outer finish. It can also be
identified by three continuous white stripes on other than green
insulation .
6. What is the maximum overcurrent protection permitted for a 14 AWG
copper conductor?
o Answer: 15 amperes
o Rationale: NEC 240.4(D) provides the standard ampacity limits for
small conductors. 14 AWG copper is rated for 15 amperes, 12 AWG for
20 amperes, and 10 AWG for 30 amperes, unless otherwise permitted
by specific exceptions .
7. What is the maximum overcurrent protection for a 12 AWG copper
conductor?
o Answer: 20 amperes
,o Rationale: As per NEC 240.4(D), a 12 AWG copper conductor must be
protected by an overcurrent device rated at a maximum of 20
amperes .
8. Is GFCI protection required for receptacles in a residential garage?
o Answer: Yes
o Rationale: NEC 210.8(A)(2) requires GFCI protection for all 125-volt,
15- and 20-ampere receptacles installed in garages and accessory
buildings. This applies regardless of whether the garage is attached or
detached .
9. Is GFCI protection required for receptacles in a residential kitchen?
o Answer: Yes
o Rationale: NEC 210.8(A)(6) requires GFCI protection for all receptacles
that serve kitchen countertop surfaces. This is to protect against
electric shock in an area where water and small appliances are
commonly used .
10. What is a primary requirement for a lighting outlet in a habitable
room?
o Answer: It must be controlled by a wall switch.
o Rationale: NEC 210.70(A)(1) requires at least one lighting outlet in
every habitable room and bathroom. This outlet must be controlled by
a wall switch, providing a user-friendly way to illuminate the space .
11. What is the minimum rating for the service disconnect for a single-
family dwelling?
o Answer: 100 amperes
o Rationale: NEC 230.79(C) states that for a one-family dwelling, the
service disconnecting means must have a rating of not less than 100
amperes. This ensures the service can handle the calculated load of
modern homes .
12. What is the purpose of an arc-fault circuit interrupter (AFCI)?
, o Answer: To protect against line-to-ground faults that could cause
arcing.
o Rationale: AFCI devices are designed to protect against the effects of
arcing faults that can cause fires. These faults can occur in branch
circuit wiring, extension cords, and even within appliances .
13. In which dwelling unit rooms is AFCI protection currently required?
o Answer: Bedrooms, living rooms, and other habitable rooms.
o Rationale: The NEC (210.12) has expanded AFCI requirements over
several code cycles. The 2023 NEC requires AFCI protection for 120-
volt, 15- and 20-ampere branch circuits supplying outlets in dwelling
unit kitchens, family rooms, dining rooms, living rooms, parlors,
libraries, dens, bedrooms, sunrooms, recreation rooms, closets,
hallways, laundry areas, and similar rooms .
14. What is the minimum height required for a receptacle installed above
a kitchen countertop?
o Answer: At least 15 inches
o Rationale: NEC 210.52(C)(5) states that receptacles installed to serve
kitchen countertops shall be located not more than 20 inches above
the countertop. The practical minimum height is often around 15-18
inches above the countertop to be above the backsplash. However,
they must be readily accessible and not behind appliances .
15. What is the minimum burial depth for an underground feeder (UF)
cable under a residential driveway?
o Answer: 24 inches
o Rationale: NEC Table 300.5 specifies the minimum cover
requirements for underground installations. For UF cable under a
driveway, which is considered a location subject to vehicle traffic, the
minimum cover is 24 inches .
16. Where must a disconnecting means be located relative to the service
equipment?
Examination Prep: Practice Questions
with Verified Answers and NEC
Rationales
1. What is the minimum size copper grounding electrode conductor
required for a 200-ampere residential service?
o Answer: 2 AWG
o Rationale: The sizing of the grounding electrode conductor is
determined by the size of the largest service-entrance conductor, not
the overcurrent device rating alone. For a typical 200-ampere
residential service, NEC Table 250.66 requires a minimum 2 AWG
copper conductor for the connection to the grounding electrode .
2. Which type of receptacle is mandated for installation in a residential
bathroom?
o Answer: GFCI protected
o Rationale: NEC 210.8(A)(1) specifically requires ground-fault circuit-
interrupter (GFCI) protection for all 125-volt, 15- and 20-ampere
receptacles installed in bathrooms. This is a critical safety requirement
to prevent electrocution in areas with high moisture .
3. What is the maximum distance allowed between receptacles along a
wall in a living room?
o Answer: 12 feet
,o Rationale: The NEC (210.52(A)(1)) requires that no point along the
wall floor line is more than 6 feet from a receptacle. This ensures that
a lamp or appliance with a standard 6-foot cord can be plugged in
without crossing a doorway, resulting in a practical maximum spacing
of 12 feet between receptacles .
4. How many 20-ampere small appliance branch circuits are required to
serve the kitchen countertop receptacles in a dwelling?
o Answer: 2 or more
o Rationale: NEC 210.11(C)(1) mandates at least two 20-ampere small-
appliance branch circuits for the receptacles in the kitchen, pantry,
breakfast room, and similar dining areas. This ensures sufficient
capacity for high-wattage countertop appliances .
5. What is the standard color identification for a neutral conductor in
residential wiring?
o Answer: White or gray
o Rationale: NEC 200.6 requires that the grounded (neutral) conductor
be identified by a continuous white or gray outer finish. It can also be
identified by three continuous white stripes on other than green
insulation .
6. What is the maximum overcurrent protection permitted for a 14 AWG
copper conductor?
o Answer: 15 amperes
o Rationale: NEC 240.4(D) provides the standard ampacity limits for
small conductors. 14 AWG copper is rated for 15 amperes, 12 AWG for
20 amperes, and 10 AWG for 30 amperes, unless otherwise permitted
by specific exceptions .
7. What is the maximum overcurrent protection for a 12 AWG copper
conductor?
o Answer: 20 amperes
,o Rationale: As per NEC 240.4(D), a 12 AWG copper conductor must be
protected by an overcurrent device rated at a maximum of 20
amperes .
8. Is GFCI protection required for receptacles in a residential garage?
o Answer: Yes
o Rationale: NEC 210.8(A)(2) requires GFCI protection for all 125-volt,
15- and 20-ampere receptacles installed in garages and accessory
buildings. This applies regardless of whether the garage is attached or
detached .
9. Is GFCI protection required for receptacles in a residential kitchen?
o Answer: Yes
o Rationale: NEC 210.8(A)(6) requires GFCI protection for all receptacles
that serve kitchen countertop surfaces. This is to protect against
electric shock in an area where water and small appliances are
commonly used .
10. What is a primary requirement for a lighting outlet in a habitable
room?
o Answer: It must be controlled by a wall switch.
o Rationale: NEC 210.70(A)(1) requires at least one lighting outlet in
every habitable room and bathroom. This outlet must be controlled by
a wall switch, providing a user-friendly way to illuminate the space .
11. What is the minimum rating for the service disconnect for a single-
family dwelling?
o Answer: 100 amperes
o Rationale: NEC 230.79(C) states that for a one-family dwelling, the
service disconnecting means must have a rating of not less than 100
amperes. This ensures the service can handle the calculated load of
modern homes .
12. What is the purpose of an arc-fault circuit interrupter (AFCI)?
, o Answer: To protect against line-to-ground faults that could cause
arcing.
o Rationale: AFCI devices are designed to protect against the effects of
arcing faults that can cause fires. These faults can occur in branch
circuit wiring, extension cords, and even within appliances .
13. In which dwelling unit rooms is AFCI protection currently required?
o Answer: Bedrooms, living rooms, and other habitable rooms.
o Rationale: The NEC (210.12) has expanded AFCI requirements over
several code cycles. The 2023 NEC requires AFCI protection for 120-
volt, 15- and 20-ampere branch circuits supplying outlets in dwelling
unit kitchens, family rooms, dining rooms, living rooms, parlors,
libraries, dens, bedrooms, sunrooms, recreation rooms, closets,
hallways, laundry areas, and similar rooms .
14. What is the minimum height required for a receptacle installed above
a kitchen countertop?
o Answer: At least 15 inches
o Rationale: NEC 210.52(C)(5) states that receptacles installed to serve
kitchen countertops shall be located not more than 20 inches above
the countertop. The practical minimum height is often around 15-18
inches above the countertop to be above the backsplash. However,
they must be readily accessible and not behind appliances .
15. What is the minimum burial depth for an underground feeder (UF)
cable under a residential driveway?
o Answer: 24 inches
o Rationale: NEC Table 300.5 specifies the minimum cover
requirements for underground installations. For UF cable under a
driveway, which is considered a location subject to vehicle traffic, the
minimum cover is 24 inches .
16. Where must a disconnecting means be located relative to the service
equipment?
