- A
The power supply is not compatible with the motherboard.
Why wrong: While compatibility is important, the most common safety-related oversight is the voltage selector switch. Incompatibility would usually cause different symptoms.
- B
The power cord is not securely plugged into the power supply.
Why wrong: This is a simple connection issue, not a safety oversight. The question asks for a safety-related oversight.
- C
The voltage selector switch on the power supply is set to the wrong voltage.
This is correct. The voltage selector switch must match the outlet voltage. An incorrect setting can prevent power-up and damage the power supply.
- D
The power supply fan is blocked by debris.
Why wrong: A blocked fan could cause overheating later, but it would not prevent the computer from powering on initially.
Quick Answer
The answer is the voltage selector switch on the power supply being set to the wrong voltage. This is the most likely safety-related oversight because the switch must match the local mains voltage—typically 115V in North America or 230V in Europe. If the switch is set to 230V while the computer is plugged into a 115V outlet, the power supply receives insufficient voltage to start, causing the system to appear completely dead with no fan spin or lights. On the CompTIA A+ Core 2 220-1202 exam, this scenario tests your understanding of power supply installation safety and common troubleshooting oversights. A frequent trap is assuming a dead power supply is defective, when the real issue is an overlooked switch setting. To remember this, think “115 for the 5 (North America), 230 for the 30 (Europe)”—always check the switch before replacing the PSU.
220-1202 Safety Procedures and Compliance Practice Question
This 220-1202 practice question tests your understanding of safety procedures and compliance. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A technician is installing a new power supply in a desktop computer. After connecting all cables, the computer will not power on. What is the most likely safety-related oversight?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue:
"most likely"Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
The voltage selector switch on the power supply is set to the wrong voltage.
The voltage selector switch on the power supply must match the local mains voltage (typically 115V in North America or 230V in Europe). If set to 230V while plugged into a 115V outlet, the power supply will receive insufficient voltage to start, causing the computer to appear completely dead. This is a common safety-related oversight because the switch is often overlooked during installation.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
The power supply is not compatible with the motherboard.
Why it's wrong here
While compatibility is important, the most common safety-related oversight is the voltage selector switch. Incompatibility would usually cause different symptoms.
- ✗
The power cord is not securely plugged into the power supply.
Why it's wrong here
This is a simple connection issue, not a safety oversight. The question asks for a safety-related oversight.
- ✓
The voltage selector switch on the power supply is set to the wrong voltage.
Why this is correct
This is correct. The voltage selector switch must match the outlet voltage. An incorrect setting can prevent power-up and damage the power supply.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
The power supply fan is blocked by debris.
Why it's wrong here
A blocked fan could cause overheating later, but it would not prevent the computer from powering on initially.
Common exam traps
Common exam trap: answer the scenario, not the keyword
CompTIA often tests the voltage selector switch as a safety-related oversight because candidates mistakenly focus on physical connection issues (like a loose power cord) or component compatibility, overlooking the critical step of matching the power supply to the local mains voltage.
Detailed technical explanation
How to think about this question
The voltage selector switch is a mechanical switch that configures the power supply's input rectifier circuit to operate in either voltage-doubling mode (for 115V) or bridge-rectifier mode (for 230V). If set incorrectly, the power supply may fail to produce the required DC output voltages (e.g., +3.3V, +5V, +12V) because the primary-side capacitors do not charge to the correct level, preventing the power supply from starting. In some modern power supplies, this switch is absent and the unit is auto-switching, but on units with a manual switch, this is a classic oversight.
KKey Concepts to Remember
- Read the scenario before looking for a memorised answer.
- Find the constraint that changes the correct option.
- Eliminate answers that are true in general but not in this case.
TExam Day Tips
- Watch for words such as best, first, most likely and least administrative effort.
- Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A small business has 20 workstations on the 192.168.1.0/24 network and one public IP from its ISP. The router uses PAT (NAT overload) so all 20 devices share one public address using different source ports. NAT questions test whether you understand the four address terms and which direction each translation applies.
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
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Safety Procedures and Compliance — study guide chapter
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FAQ
Questions learners often ask
What does this 220-1202 question test?
Safety Procedures and Compliance — This question tests Safety Procedures and Compliance — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: The voltage selector switch on the power supply is set to the wrong voltage. — The voltage selector switch on the power supply must match the local mains voltage (typically 115V in North America or 230V in Europe). If set to 230V while plugged into a 115V outlet, the power supply will receive insufficient voltage to start, causing the computer to appear completely dead. This is a common safety-related oversight because the switch is often overlooked during installation.
What should I do if I get this 220-1202 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Are there clue words in this question I should notice?
Yes — watch for: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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Last reviewed: Jun 30, 2026
This 220-1202 practice question is part of Courseiva's free CompTIA certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the 220-1202 exam.
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