Maryland Master Electrician Practice
Exam Questions with Correct Answers
(Verified Answers) Plus Rationales 2026
Q&A | Instant Download Pdf
1. What electrical quantity is measured in volts?
A. Resistance
B. Current
C. Potential difference
D. Power
Rationale: Voltage is the electrical potential difference between two points. It
represents the electrical pressure that causes current to flow through an
impedance.
2. A 240-volt heating element has a resistance of 24 ohms. What current does it
draw?
A. 5 A
B. 10 A
C. 20 A
D. 24 A
Rationale: Ohm's law states that I = E/R. Therefore, 240 V ÷ 24 Ω = 10 A.
3. Which condition produces the greatest voltage drop in a conductor when
conductor size remains unchanged?
A. Decreasing circuit length
B. Decreasing load current
,C. Increasing conductor size
D. Increasing circuit length
Rationale: Conductor resistance increases with length. With the conductor size
and load otherwise unchanged, a longer circuit produces greater voltage drop.
4. A 120-volt load draws 8 amperes. What is its power consumption?
A. 15 W
B. 960 W
C. 960 W
D. 128 W
Rationale: For a unity-power-factor load, power is calculated as P = E × I. Thus,
120 V × 8 A = 960 W.
5. Which instrument is most appropriate for measuring current without opening
the circuit?
A. Megohmmeter
B. Clamp ammeter
C. Ohmmeter
D. Phase-sequence indicator
Rationale: A clamp ammeter measures current by sensing the magnetic field
surrounding a conductor. This permits current measurement without
disconnecting the conductor in normal applications.
6. What happens to the total resistance when two equal resistors are connected
in parallel?
A. It doubles
B. It remains equal to one resistor
C. It becomes one-half the resistance of one resistor
D. It becomes four times the resistance
,Rationale: For two equal resistors in parallel, the equivalent resistance is R/2.
Parallel circuits provide multiple current paths, reducing total resistance.
7. A 120/240-volt single-phase system has 120 volts from each ungrounded
conductor to neutral. What is the voltage between the two ungrounded
conductors?
A. 120 V
B. 208 V
C. 240 V
D. 480 V
Rationale: The two ungrounded conductors in a typical 120/240-volt single-phase
system are opposite in phase, producing 240 volts between them.
8. What is the primary purpose of an equipment grounding conductor?
A. To carry normal neutral current
B. To increase circuit voltage
C. To reduce the normal operating current
D. To provide an effective path for fault current
Rationale: The equipment grounding conductor connects normally non-current-
carrying metal parts to the grounding system and provides a low-impedance path
for fault current so protective devices can operate.
9. Which conductor identification is normally associated with a grounded circuit
conductor?
A. Green
B. Orange
C. White or gray
D. Green with yellow stripes
, Rationale: Grounded circuit conductors are generally identified with white or gray
insulation or other permitted identification methods. Green is generally associated
with equipment grounding conductors.
10. What is the primary function of overcurrent protection?
A. To increase available fault current
B. To protect conductors and equipment from excessive current
C. To increase motor speed
D. To stabilize utility frequency
Rationale: Fuses and circuit breakers limit excessive current caused by overloads
and faults, protecting conductors and equipment from damage.
11. A continuous load is calculated at 16 amperes. What minimum ampacity is
required when applying the 125% continuous-load factor?
A. 16 A
B. 18 A
C. 20 A
D. 24 A
Rationale: A continuous load is generally multiplied by 125%. Thus, 16 A × 1.25 =
20 A.
12. Which NEC article primarily addresses grounding and bonding?
A. Article 110
B. Article 210
C. Article 240
D. Article 250
Rationale: NEC Article 250 contains the principal requirements for grounding and
bonding electrical systems and equipment.
Exam Questions with Correct Answers
(Verified Answers) Plus Rationales 2026
Q&A | Instant Download Pdf
1. What electrical quantity is measured in volts?
A. Resistance
B. Current
C. Potential difference
D. Power
Rationale: Voltage is the electrical potential difference between two points. It
represents the electrical pressure that causes current to flow through an
impedance.
2. A 240-volt heating element has a resistance of 24 ohms. What current does it
draw?
A. 5 A
B. 10 A
C. 20 A
D. 24 A
Rationale: Ohm's law states that I = E/R. Therefore, 240 V ÷ 24 Ω = 10 A.
3. Which condition produces the greatest voltage drop in a conductor when
conductor size remains unchanged?
A. Decreasing circuit length
B. Decreasing load current
,C. Increasing conductor size
D. Increasing circuit length
Rationale: Conductor resistance increases with length. With the conductor size
and load otherwise unchanged, a longer circuit produces greater voltage drop.
4. A 120-volt load draws 8 amperes. What is its power consumption?
A. 15 W
B. 960 W
C. 960 W
D. 128 W
Rationale: For a unity-power-factor load, power is calculated as P = E × I. Thus,
120 V × 8 A = 960 W.
5. Which instrument is most appropriate for measuring current without opening
the circuit?
A. Megohmmeter
B. Clamp ammeter
C. Ohmmeter
D. Phase-sequence indicator
Rationale: A clamp ammeter measures current by sensing the magnetic field
surrounding a conductor. This permits current measurement without
disconnecting the conductor in normal applications.
6. What happens to the total resistance when two equal resistors are connected
in parallel?
A. It doubles
B. It remains equal to one resistor
C. It becomes one-half the resistance of one resistor
D. It becomes four times the resistance
,Rationale: For two equal resistors in parallel, the equivalent resistance is R/2.
Parallel circuits provide multiple current paths, reducing total resistance.
7. A 120/240-volt single-phase system has 120 volts from each ungrounded
conductor to neutral. What is the voltage between the two ungrounded
conductors?
A. 120 V
B. 208 V
C. 240 V
D. 480 V
Rationale: The two ungrounded conductors in a typical 120/240-volt single-phase
system are opposite in phase, producing 240 volts between them.
8. What is the primary purpose of an equipment grounding conductor?
A. To carry normal neutral current
B. To increase circuit voltage
C. To reduce the normal operating current
D. To provide an effective path for fault current
Rationale: The equipment grounding conductor connects normally non-current-
carrying metal parts to the grounding system and provides a low-impedance path
for fault current so protective devices can operate.
9. Which conductor identification is normally associated with a grounded circuit
conductor?
A. Green
B. Orange
C. White or gray
D. Green with yellow stripes
, Rationale: Grounded circuit conductors are generally identified with white or gray
insulation or other permitted identification methods. Green is generally associated
with equipment grounding conductors.
10. What is the primary function of overcurrent protection?
A. To increase available fault current
B. To protect conductors and equipment from excessive current
C. To increase motor speed
D. To stabilize utility frequency
Rationale: Fuses and circuit breakers limit excessive current caused by overloads
and faults, protecting conductors and equipment from damage.
11. A continuous load is calculated at 16 amperes. What minimum ampacity is
required when applying the 125% continuous-load factor?
A. 16 A
B. 18 A
C. 20 A
D. 24 A
Rationale: A continuous load is generally multiplied by 125%. Thus, 16 A × 1.25 =
20 A.
12. Which NEC article primarily addresses grounding and bonding?
A. Article 110
B. Article 210
C. Article 240
D. Article 250
Rationale: NEC Article 250 contains the principal requirements for grounding and
bonding electrical systems and equipment.
