ASTM NCATT Electrical Troubleshooting
Assessment Newest (2025 - 2026
Update) From Real Past Papers
Questions – A Set Of 100 Most Common
Exam Frequently Tested Questions And
Answers In Details 100% Verified Exam
Highly Recommendable For Grade A+
1. A technician is troubleshooting a circuit with no voltage at the load. What
should be checked first?
A. Replace the load
B. Verify the power source
C. Replace the switch
D. Replace the wiring
Answer: B. Verify the power source
Explanation: Troubleshooting begins by confirming that the circuit has a proper
power supply before investigating downstream components.
2. Which instrument is most commonly used to measure voltage?
A. Clamp meter
B. Megohmmeter
C. Digital multimeter
,D. Oscilloscope
Answer: C. Digital multimeter
Explanation: A digital multimeter is the standard instrument for measuring AC and
DC voltage.
3. An open circuit is best described as:
A. Excessive current flow
B. Low resistance
C. Broken current path
D. High voltage condition
Answer: C. Broken current path
Explanation: An open circuit interrupts current flow by creating a break in the
electrical path.
4. Before measuring resistance, power should be:
A. Increased
B. Reduced
C. Left on
D. Turned off
Answer: D. Turned off
Explanation: Resistance measurements must be performed on de-energized
circuits to prevent inaccurate readings and meter damage.
5. A blown fuse usually indicates:
A. Low voltage
B. High resistance
C. Excessive current
,D. Open neutral
Answer: C. Excessive current
Explanation: Fuses open when current exceeds their rated value to protect the
circuit.
6. Which troubleshooting method isolates sections of a circuit until the fault is
located?
A. Guess-and-check
B. Replacement method
C. Divide-and-conquer
D. Random testing
Answer: C. Divide-and-conquer
Explanation: Dividing the circuit into sections quickly narrows down the location of
a fault.
7. Zero ohms across a closed switch indicates:
A. Faulty contacts
B. Open circuit
C. High resistance
D. Good continuity
Answer: D. Good continuity
Explanation: A closed switch should provide a nearly resistance-free path.
8. Infinite resistance across a closed switch indicates:
A. Proper operation
B. Low voltage
C. Open contacts or defective switch
, D. Short circuit
Answer: C. Open contacts or defective switch
Explanation: A closed switch should not measure infinite resistance.
9. A short circuit generally results in:
A. Low current
B. High resistance
C. Very high current flow
D. No current
Answer: C. Very high current flow
Explanation: Shorts reduce circuit resistance and dramatically increase current.
10.The first safety step before troubleshooting energized equipment is to:
A. Replace components
B. Disconnect the load
C. Wear appropriate PPE
D. Remove the fuse
Answer: C. Wear appropriate PPE
Explanation: Proper personal protective equipment reduces shock and arc-flash
hazards.
11.Continuity testing determines whether:
A. Voltage is present
B. Frequency is correct
C. A complete electrical path exists
D. Current is excessive
Assessment Newest (2025 - 2026
Update) From Real Past Papers
Questions – A Set Of 100 Most Common
Exam Frequently Tested Questions And
Answers In Details 100% Verified Exam
Highly Recommendable For Grade A+
1. A technician is troubleshooting a circuit with no voltage at the load. What
should be checked first?
A. Replace the load
B. Verify the power source
C. Replace the switch
D. Replace the wiring
Answer: B. Verify the power source
Explanation: Troubleshooting begins by confirming that the circuit has a proper
power supply before investigating downstream components.
2. Which instrument is most commonly used to measure voltage?
A. Clamp meter
B. Megohmmeter
C. Digital multimeter
,D. Oscilloscope
Answer: C. Digital multimeter
Explanation: A digital multimeter is the standard instrument for measuring AC and
DC voltage.
3. An open circuit is best described as:
A. Excessive current flow
B. Low resistance
C. Broken current path
D. High voltage condition
Answer: C. Broken current path
Explanation: An open circuit interrupts current flow by creating a break in the
electrical path.
4. Before measuring resistance, power should be:
A. Increased
B. Reduced
C. Left on
D. Turned off
Answer: D. Turned off
Explanation: Resistance measurements must be performed on de-energized
circuits to prevent inaccurate readings and meter damage.
5. A blown fuse usually indicates:
A. Low voltage
B. High resistance
C. Excessive current
,D. Open neutral
Answer: C. Excessive current
Explanation: Fuses open when current exceeds their rated value to protect the
circuit.
6. Which troubleshooting method isolates sections of a circuit until the fault is
located?
A. Guess-and-check
B. Replacement method
C. Divide-and-conquer
D. Random testing
Answer: C. Divide-and-conquer
Explanation: Dividing the circuit into sections quickly narrows down the location of
a fault.
7. Zero ohms across a closed switch indicates:
A. Faulty contacts
B. Open circuit
C. High resistance
D. Good continuity
Answer: D. Good continuity
Explanation: A closed switch should provide a nearly resistance-free path.
8. Infinite resistance across a closed switch indicates:
A. Proper operation
B. Low voltage
C. Open contacts or defective switch
, D. Short circuit
Answer: C. Open contacts or defective switch
Explanation: A closed switch should not measure infinite resistance.
9. A short circuit generally results in:
A. Low current
B. High resistance
C. Very high current flow
D. No current
Answer: C. Very high current flow
Explanation: Shorts reduce circuit resistance and dramatically increase current.
10.The first safety step before troubleshooting energized equipment is to:
A. Replace components
B. Disconnect the load
C. Wear appropriate PPE
D. Remove the fuse
Answer: C. Wear appropriate PPE
Explanation: Proper personal protective equipment reduces shock and arc-flash
hazards.
11.Continuity testing determines whether:
A. Voltage is present
B. Frequency is correct
C. A complete electrical path exists
D. Current is excessive
