Construction Electrician Level 3 Exam
Questions with Correct Answers
(VerifiedAnswers) Plus Rationales 2026 Q&A
Instant Download PDF
Question 1
A 240 V single-phase load draws 15 A. What is the approximate
power consumed by the load?
A. 1,600 W
B. 2,400 W
C. 3,600 W
D. 4,800 W
Rationale: Electrical power in a single-phase resistive circuit can
be calculated using P = V × I. Therefore, 240 V × 15 A = 3,600 W.
Understanding the relationship between voltage, current,
resistance, and power is fundamental for sizing conductors,
overcurrent protection, and electrical equipment.
Question 2
What is the primary purpose of an overcurrent protective
device such as a circuit breaker?
,A. To increase circuit voltage
B. To improve power factor
C. To provide a path for normal current
D. To protect conductors and equipment from excessive
current
Rationale: Circuit breakers and fuses are designed to interrupt
excessive current before conductors or equipment are damaged.
Excessive current can result from overloads, short circuits, or
ground faults. The protective device must be properly
coordinated with the circuit conductors and equipment.
Question 3
In a series circuit, which quantity is the same through every
component?
A. Voltage
B. Resistance
C. Power
D. Current
Rationale: In a series circuit, there is only one continuous path
for current. Consequently, the same current flows through every
component. Voltage is divided among the loads according to
their resistance, while the total resistance is the sum of the
individual resistances.
Question 4
,What happens to total resistance when two equal resistors are
connected in parallel?
A. It doubles
B. It remains unchanged
C. It becomes half the resistance of one resistor
D. It becomes four times the resistance
Rationale: Parallel circuits provide multiple paths for current,
reducing total resistance. For two equal resistors, the equivalent
resistance is R/2. For example, two 10 Ω resistors in parallel
produce an equivalent resistance of 5 Ω.
Question 5
Which instrument is specifically designed to measure current
without opening the circuit?
A. Megohmmeter
B. Voltmeter
C. Clamp meter
D. Phase-sequence meter
Rationale: A clamp meter measures current by sensing the
magnetic field produced around a conductor. This allows an
electrician to measure current without disconnecting the
conductor or placing the meter directly in series with the circuit.
This feature is particularly useful during troubleshooting and
commissioning.
, Question 6
What is the main purpose of a transformer?
A. To convert AC into mechanical energy
B. To store electrical energy permanently
C. To change AC voltage and current levels through
electromagnetic induction
D. To eliminate all electrical resistance
Rationale: A transformer transfers electrical energy between
circuits through electromagnetic induction. Depending on its
turns ratio, it can step voltage up or down. Transformers
operate with alternating current because changing magnetic
flux is required to induce voltage in the secondary winding.
Question 7
A transformer has more turns on its secondary winding than on
its primary winding. What type of transformer is it?
A. Isolation transformer only
B. Step-down transformer
C. Step-up transformer
D. Current-limiting transformer
Rationale: Transformer voltage is proportional to the ratio of
secondary turns to primary turns. When the secondary has
more turns than the primary, the secondary voltage is higher
than the primary voltage, making it a step-up transformer.
Questions with Correct Answers
(VerifiedAnswers) Plus Rationales 2026 Q&A
Instant Download PDF
Question 1
A 240 V single-phase load draws 15 A. What is the approximate
power consumed by the load?
A. 1,600 W
B. 2,400 W
C. 3,600 W
D. 4,800 W
Rationale: Electrical power in a single-phase resistive circuit can
be calculated using P = V × I. Therefore, 240 V × 15 A = 3,600 W.
Understanding the relationship between voltage, current,
resistance, and power is fundamental for sizing conductors,
overcurrent protection, and electrical equipment.
Question 2
What is the primary purpose of an overcurrent protective
device such as a circuit breaker?
,A. To increase circuit voltage
B. To improve power factor
C. To provide a path for normal current
D. To protect conductors and equipment from excessive
current
Rationale: Circuit breakers and fuses are designed to interrupt
excessive current before conductors or equipment are damaged.
Excessive current can result from overloads, short circuits, or
ground faults. The protective device must be properly
coordinated with the circuit conductors and equipment.
Question 3
In a series circuit, which quantity is the same through every
component?
A. Voltage
B. Resistance
C. Power
D. Current
Rationale: In a series circuit, there is only one continuous path
for current. Consequently, the same current flows through every
component. Voltage is divided among the loads according to
their resistance, while the total resistance is the sum of the
individual resistances.
Question 4
,What happens to total resistance when two equal resistors are
connected in parallel?
A. It doubles
B. It remains unchanged
C. It becomes half the resistance of one resistor
D. It becomes four times the resistance
Rationale: Parallel circuits provide multiple paths for current,
reducing total resistance. For two equal resistors, the equivalent
resistance is R/2. For example, two 10 Ω resistors in parallel
produce an equivalent resistance of 5 Ω.
Question 5
Which instrument is specifically designed to measure current
without opening the circuit?
A. Megohmmeter
B. Voltmeter
C. Clamp meter
D. Phase-sequence meter
Rationale: A clamp meter measures current by sensing the
magnetic field produced around a conductor. This allows an
electrician to measure current without disconnecting the
conductor or placing the meter directly in series with the circuit.
This feature is particularly useful during troubleshooting and
commissioning.
, Question 6
What is the main purpose of a transformer?
A. To convert AC into mechanical energy
B. To store electrical energy permanently
C. To change AC voltage and current levels through
electromagnetic induction
D. To eliminate all electrical resistance
Rationale: A transformer transfers electrical energy between
circuits through electromagnetic induction. Depending on its
turns ratio, it can step voltage up or down. Transformers
operate with alternating current because changing magnetic
flux is required to induce voltage in the secondary winding.
Question 7
A transformer has more turns on its secondary winding than on
its primary winding. What type of transformer is it?
A. Isolation transformer only
B. Step-down transformer
C. Step-up transformer
D. Current-limiting transformer
Rationale: Transformer voltage is proportional to the ratio of
secondary turns to primary turns. When the secondary has
more turns than the primary, the secondary voltage is higher
than the primary voltage, making it a step-up transformer.
