MARYLAND MASTER ELECTRICIAN NEC
COMPREHENSIVE PRACTICE EXAM WITH
QUESTIONS AND VERIFIED ANSWERS,
PLUS DETAILED RATIONALES/EXPERT
VERIFIED FOR GUARANTEED PASS
2026/LATEST UPDATE/INSTANT
DOWNLOAD PDF
1.
A 120/240-volt single-phase service supplies a dwelling with a
calculated load of 72 amperes. The service-entrance conductors are
copper THHN/THWN-2 conductors installed in a raceway. The
terminals of the service equipment are listed for conductors rated 75°C.
Which conductor ampacity is generally appropriate for determining the
minimum size of the service-entrance conductors, assuming no other
adjustment or correction factors reduce the allowable ampacity?
A. 60 amperes based on the 60°C column
B. 70 amperes based on the 60°C column
C. 75 amperes based on the 75°C column
D. 85 amperes based on the 90°C column
Answer: C. 75 amperes based on the 75°C column
Rationale: When equipment is listed for use with conductors rated
75°C and the applicable conditions permit use of that column, the
75°C ampacity column is used for conductors sized under the
applicable NEC rules. The 90°C rating of THHN may be useful for
adjustment and correction calculations, but it does not automatically
mean the final conductor ampacity can be taken from the 90°C
column. The 60°C limitation generally applies to smaller conductors
1
,and certain equipment conditions, while equipment rated for 75°C
permits the higher column where the Code allows it.
2.
A 120-volt branch circuit supplies a continuous load of 16 amperes. No
other loads are connected to the circuit. What is the minimum branch-
circuit rating required for this continuous load?
A. 15 amperes
B. 16 amperes
C. 18 amperes
D. 20 amperes
Answer: D. 20 amperes
Rationale: A continuous load is generally calculated at 125% of its
actual load unless a specific provision permits otherwise. Therefore, 16
amperes × 125% = 20 amperes. A 15-ampere branch circuit cannot
legally supply this load merely because the actual measured load is 16
amperes; the continuous-load multiplier must be applied when sizing
the branch circuit and associated conductors.
3.
A 240-volt single-phase heating load consists of a 4,800-watt resistance
heater. Ignoring conductor and overcurrent-protection requirements for
the moment, what current does the heater draw?
A. 10 amperes
B. 20 amperes
C. 24 amperes
D. 40 amperes
Answer: B. 20 amperes
2
,Rationale: For a substantially resistive single-phase load, current can
be calculated using I = P ÷ E. Thus, 4,800 W ÷ 240 V = 20 A. This
calculation is fundamental for determining conductor size,
overcurrent protection, disconnect requirements, and the appropriate
branch-circuit rating. If the heater represents a continuous load, the
calculated load would subsequently be multiplied by 125% for sizing
purposes.
4.
A panelboard contains several branch circuits. An electrician installs a
neutral conductor that is bonded to the panelboard enclosure with the
bonding screw in a downstream panel supplied by a feeder. Which
statement is correct?
A. The bonding screw is required in every panelboard
B. The neutral-to-ground bond is generally permitted only at the service
disconnecting means for a typical grounded system
C. The neutral must be bonded in every panelboard to ensure low
impedance
D. The neutral must be bonded only when the feeder contains an
equipment grounding conductor
Answer: B. The neutral-to-ground bond is generally permitted only
at the service disconnecting means for a typical grounded system
Rationale: In a typical separately supplied feeder to a downstream
panel, the grounded conductor is isolated from the equipment
grounding/bonding system. Bonding the neutral to the enclosure
downstream of the service disconnect creates objectionable parallel
current paths on equipment grounding paths and metal enclosures.
The equipment grounding conductor provides the grounding/bonding
path back to the source while the neutral remains isolated
downstream.
3
, 5.
A conductor is protected by a 100-ampere overcurrent device. Under
ordinary conditions, the conductor must have an allowable ampacity of
at least:
A. 80 amperes
B. 90 amperes
C. 100 amperes
D. 125 amperes
Answer: C. 100 amperes
Rationale: Conductors are generally required to have an allowable
ampacity sufficient for the load and the overcurrent protection, subject
to the specific conductor-sizing rules and permitted exceptions. A 100-
ampere protective device does not normally allow an 80- or 90-ampere
conductor simply because the load might be smaller. Special
provisions, including standard-size overcurrent-device rules and
specific conductor applications, can create exceptions, but the basic
rule requires the conductor ampacity to be appropriately protected.
6.
A 120-volt, 20-ampere branch circuit supplies receptacles in a location
where personnel are likely to use portable cord-and-plug-connected
equipment. Which protection is generally required where the NEC
identifies the location as requiring ground-fault protection?
A. AFCI only
B. GFCI protection
C. Surge protection only
D. Overvoltage protection only
4
COMPREHENSIVE PRACTICE EXAM WITH
QUESTIONS AND VERIFIED ANSWERS,
PLUS DETAILED RATIONALES/EXPERT
VERIFIED FOR GUARANTEED PASS
2026/LATEST UPDATE/INSTANT
DOWNLOAD PDF
1.
A 120/240-volt single-phase service supplies a dwelling with a
calculated load of 72 amperes. The service-entrance conductors are
copper THHN/THWN-2 conductors installed in a raceway. The
terminals of the service equipment are listed for conductors rated 75°C.
Which conductor ampacity is generally appropriate for determining the
minimum size of the service-entrance conductors, assuming no other
adjustment or correction factors reduce the allowable ampacity?
A. 60 amperes based on the 60°C column
B. 70 amperes based on the 60°C column
C. 75 amperes based on the 75°C column
D. 85 amperes based on the 90°C column
Answer: C. 75 amperes based on the 75°C column
Rationale: When equipment is listed for use with conductors rated
75°C and the applicable conditions permit use of that column, the
75°C ampacity column is used for conductors sized under the
applicable NEC rules. The 90°C rating of THHN may be useful for
adjustment and correction calculations, but it does not automatically
mean the final conductor ampacity can be taken from the 90°C
column. The 60°C limitation generally applies to smaller conductors
1
,and certain equipment conditions, while equipment rated for 75°C
permits the higher column where the Code allows it.
2.
A 120-volt branch circuit supplies a continuous load of 16 amperes. No
other loads are connected to the circuit. What is the minimum branch-
circuit rating required for this continuous load?
A. 15 amperes
B. 16 amperes
C. 18 amperes
D. 20 amperes
Answer: D. 20 amperes
Rationale: A continuous load is generally calculated at 125% of its
actual load unless a specific provision permits otherwise. Therefore, 16
amperes × 125% = 20 amperes. A 15-ampere branch circuit cannot
legally supply this load merely because the actual measured load is 16
amperes; the continuous-load multiplier must be applied when sizing
the branch circuit and associated conductors.
3.
A 240-volt single-phase heating load consists of a 4,800-watt resistance
heater. Ignoring conductor and overcurrent-protection requirements for
the moment, what current does the heater draw?
A. 10 amperes
B. 20 amperes
C. 24 amperes
D. 40 amperes
Answer: B. 20 amperes
2
,Rationale: For a substantially resistive single-phase load, current can
be calculated using I = P ÷ E. Thus, 4,800 W ÷ 240 V = 20 A. This
calculation is fundamental for determining conductor size,
overcurrent protection, disconnect requirements, and the appropriate
branch-circuit rating. If the heater represents a continuous load, the
calculated load would subsequently be multiplied by 125% for sizing
purposes.
4.
A panelboard contains several branch circuits. An electrician installs a
neutral conductor that is bonded to the panelboard enclosure with the
bonding screw in a downstream panel supplied by a feeder. Which
statement is correct?
A. The bonding screw is required in every panelboard
B. The neutral-to-ground bond is generally permitted only at the service
disconnecting means for a typical grounded system
C. The neutral must be bonded in every panelboard to ensure low
impedance
D. The neutral must be bonded only when the feeder contains an
equipment grounding conductor
Answer: B. The neutral-to-ground bond is generally permitted only
at the service disconnecting means for a typical grounded system
Rationale: In a typical separately supplied feeder to a downstream
panel, the grounded conductor is isolated from the equipment
grounding/bonding system. Bonding the neutral to the enclosure
downstream of the service disconnect creates objectionable parallel
current paths on equipment grounding paths and metal enclosures.
The equipment grounding conductor provides the grounding/bonding
path back to the source while the neutral remains isolated
downstream.
3
, 5.
A conductor is protected by a 100-ampere overcurrent device. Under
ordinary conditions, the conductor must have an allowable ampacity of
at least:
A. 80 amperes
B. 90 amperes
C. 100 amperes
D. 125 amperes
Answer: C. 100 amperes
Rationale: Conductors are generally required to have an allowable
ampacity sufficient for the load and the overcurrent protection, subject
to the specific conductor-sizing rules and permitted exceptions. A 100-
ampere protective device does not normally allow an 80- or 90-ampere
conductor simply because the load might be smaller. Special
provisions, including standard-size overcurrent-device rules and
specific conductor applications, can create exceptions, but the basic
rule requires the conductor ampacity to be appropriately protected.
6.
A 120-volt, 20-ampere branch circuit supplies receptacles in a location
where personnel are likely to use portable cord-and-plug-connected
equipment. Which protection is generally required where the NEC
identifies the location as requiring ground-fault protection?
A. AFCI only
B. GFCI protection
C. Surge protection only
D. Overvoltage protection only
4
