Pennsylvania Master Electrician Exam
Practice Questions and Correct Answers
(Verified Answers) Plus Rationales 2027
Q&A | Instant Download Pdf
Question 1 — General Knowledge
What is the primary purpose of the National Electrical Code?
A. To establish electrical utility rates
B. To regulate electrician wages
C. To provide practical safeguards for persons and property from electrical
hazards
D. To establish equipment manufacturing costs
Rationale: The NEC is primarily a safety standard. Its provisions are intended to
protect people and property from hazards associated with the use of electricity.
Question 2 — General Knowledge
Which NEC chapter contains the definitions used throughout the Code?
A. Chapter 2
B. Chapter 1
C. Chapter 3
D. Chapter 9
Rationale: Article 100, which contains many important NEC definitions, is located
in Chapter 1. Correctly understanding defined terms is essential when applying
Code requirements.
Question 3 — General Knowledge
Which NEC article primarily addresses grounding and bonding?
,A. Article 110
B. Article 210
C. Article 225
D. Article 250
Rationale: Article 250 contains the principal NEC requirements for grounding and
bonding, including grounding electrode systems, equipment grounding
conductors, bonding, and related requirements.
Question 4 — General Knowledge
An electrical plan shows a circuit identified as “2-20A-1P.” What does the “1P”
generally indicate about the circuit breaker?
A. It is rated for one ampere
B. It has one terminal
C. It is a single-pole breaker
D. It is a one-phase transformer
Rationale: “1P” commonly identifies a single-pole device. A single-pole breaker
normally supplies a 120-volt circuit from one ungrounded conductor in a typical
single-phase system.
Question 5 — General Knowledge
What does a one-line diagram primarily represent?
A. The physical dimensions of an electrical room
B. The general arrangement and relationships of electrical system components
C. The exact routing of every conductor
D. The manufacturer's internal wiring of each device
Rationale: A one-line diagram provides a simplified representation of an electrical
distribution system, showing relationships among services, transformers,
switchgear, feeders, and other major components.
,Question 6 — General Knowledge
What is the electrical relationship expressed by Ohm's law?
A. P = VI
B. P = I²R
C. E = IR²
D. E = IR
Rationale: Ohm's law states that voltage, or electromotive force, equals current
multiplied by resistance: E = I × R. The other formulas describe power relationships
or are not valid Ohm's-law equations.
Question 7 — General Knowledge
A circuit has 240 volts applied to a resistance of 12 ohms. What current flows
through the resistance?
A. 10 amperes
B. 20 amperes
C. 24 amperes
D. 28.8 amperes
Rationale: Using Ohm's law, I = E/R. Therefore, 240 ÷ 12 = 20 amperes.
Question 8 — General Knowledge
What is the primary purpose of an electrical load schedule on a set of plans?
A. To identify only the building's lighting fixtures
B. To determine utility ownership of equipment
C. To organize circuit, load, and equipment information for the electrical
installation
D. To replace the electrical code
Rationale: Load schedules organize information such as circuit numbers,
connected loads, demand loads, breaker sizes, and other design information. They
help the electrician understand and verify the planned electrical distribution.
, Question 9 — General Knowledge
Which unit is used to express electrical power?
A. Ohm
B. Volt
C. Ampere
D. Watt
Rationale: The watt is the unit of electrical power. Voltage is measured in volts,
current in amperes, and resistance in ohms.
Question 10 — General Knowledge
A 120-volt load draws 15 amperes. What is its approximate power?
A. 1,200 watts
B. 1,800 watts
C. 2,400 watts
D. 8 watts
Rationale: Power is calculated using P = V × I. Therefore, 120 × 15 = 1,800 watts.
Question 11 — Services and Service Equipment
What is the primary purpose of service equipment?
A. To control only lighting loads
B. To provide telecommunications service
C. To provide the main control and disconnecting means for the premises
electrical supply
D. To replace all branch-circuit overcurrent devices
Rationale: Service equipment includes the necessary equipment for controlling,
protecting, and disconnecting the electrical supply to a premises. It is located on
the supply side of the premises wiring system.
Practice Questions and Correct Answers
(Verified Answers) Plus Rationales 2027
Q&A | Instant Download Pdf
Question 1 — General Knowledge
What is the primary purpose of the National Electrical Code?
A. To establish electrical utility rates
B. To regulate electrician wages
C. To provide practical safeguards for persons and property from electrical
hazards
D. To establish equipment manufacturing costs
Rationale: The NEC is primarily a safety standard. Its provisions are intended to
protect people and property from hazards associated with the use of electricity.
Question 2 — General Knowledge
Which NEC chapter contains the definitions used throughout the Code?
A. Chapter 2
B. Chapter 1
C. Chapter 3
D. Chapter 9
Rationale: Article 100, which contains many important NEC definitions, is located
in Chapter 1. Correctly understanding defined terms is essential when applying
Code requirements.
Question 3 — General Knowledge
Which NEC article primarily addresses grounding and bonding?
,A. Article 110
B. Article 210
C. Article 225
D. Article 250
Rationale: Article 250 contains the principal NEC requirements for grounding and
bonding, including grounding electrode systems, equipment grounding
conductors, bonding, and related requirements.
Question 4 — General Knowledge
An electrical plan shows a circuit identified as “2-20A-1P.” What does the “1P”
generally indicate about the circuit breaker?
A. It is rated for one ampere
B. It has one terminal
C. It is a single-pole breaker
D. It is a one-phase transformer
Rationale: “1P” commonly identifies a single-pole device. A single-pole breaker
normally supplies a 120-volt circuit from one ungrounded conductor in a typical
single-phase system.
Question 5 — General Knowledge
What does a one-line diagram primarily represent?
A. The physical dimensions of an electrical room
B. The general arrangement and relationships of electrical system components
C. The exact routing of every conductor
D. The manufacturer's internal wiring of each device
Rationale: A one-line diagram provides a simplified representation of an electrical
distribution system, showing relationships among services, transformers,
switchgear, feeders, and other major components.
,Question 6 — General Knowledge
What is the electrical relationship expressed by Ohm's law?
A. P = VI
B. P = I²R
C. E = IR²
D. E = IR
Rationale: Ohm's law states that voltage, or electromotive force, equals current
multiplied by resistance: E = I × R. The other formulas describe power relationships
or are not valid Ohm's-law equations.
Question 7 — General Knowledge
A circuit has 240 volts applied to a resistance of 12 ohms. What current flows
through the resistance?
A. 10 amperes
B. 20 amperes
C. 24 amperes
D. 28.8 amperes
Rationale: Using Ohm's law, I = E/R. Therefore, 240 ÷ 12 = 20 amperes.
Question 8 — General Knowledge
What is the primary purpose of an electrical load schedule on a set of plans?
A. To identify only the building's lighting fixtures
B. To determine utility ownership of equipment
C. To organize circuit, load, and equipment information for the electrical
installation
D. To replace the electrical code
Rationale: Load schedules organize information such as circuit numbers,
connected loads, demand loads, breaker sizes, and other design information. They
help the electrician understand and verify the planned electrical distribution.
, Question 9 — General Knowledge
Which unit is used to express electrical power?
A. Ohm
B. Volt
C. Ampere
D. Watt
Rationale: The watt is the unit of electrical power. Voltage is measured in volts,
current in amperes, and resistance in ohms.
Question 10 — General Knowledge
A 120-volt load draws 15 amperes. What is its approximate power?
A. 1,200 watts
B. 1,800 watts
C. 2,400 watts
D. 8 watts
Rationale: Power is calculated using P = V × I. Therefore, 120 × 15 = 1,800 watts.
Question 11 — Services and Service Equipment
What is the primary purpose of service equipment?
A. To control only lighting loads
B. To provide telecommunications service
C. To provide the main control and disconnecting means for the premises
electrical supply
D. To replace all branch-circuit overcurrent devices
Rationale: Service equipment includes the necessary equipment for controlling,
protecting, and disconnecting the electrical supply to a premises. It is located on
the supply side of the premises wiring system.
