Power Outage Uptime for Two Switches: UPS vs. PDU and Circuits
Short answer
D Use a UPS so battery backup keeps the two switches running during a power outage, unlike separate PDUs or circuits that only distribute utility power.
Question
Key Takeaways
It tests distinguishing power distribution (PDU/circuit) from power backup (UPS); the trap is assuming separate PDUs or circuits keep switches running when utility power is lost.
This N10-009 question tests power redundancy for network switches during an outage; the best option is D, because a UPS provides battery backup that PDUs and separate circuits do not.
Common mistake: Option C is tempting because separate PDUs sound redundant, but PDUs only distribute power and do not supply battery runtime during an outage.
Expert Analysis
The tempting wrong turn: separate PDUs Option C sounds like the textbook redundancy answer: each switch gets its own power distribution unit, so a PDU failure cannot take both down. That is useful for outlet-level or PDU-level resilience, and it satisfies part of the wording about “uptime.” The single point where it stops being correct is the outage itself: a standard PDU distributes utility power; it does not generate or store power. In a building-wide outage, both PDUs go dark together.
Why separate circuits are not enough Option B has similar appeal. Different circuits protect against one breaker tripping or one branch circuit being overloaded, but they normally still trace back to the same utility feed. A power outage is not a circuit-level failure; it removes power from both circuits. This option improves availability against a local electrical fault, not against the scenario asked about.
The decisive property: battery runtime Option D is the only choice that introduces a UPS. A UPS contains batteries and an inverter, so it can continue supplying power to the switches for a period after utility power fails. That directly addresses “if a power outage occurs” and gives the switches time to ride through short outages or shut down gracefully. The wording “both switches into a different UPS” is awkward, but the exam intent is clear: use UPS-backed power rather than merely redistributed or diversified utility power. Option A is weaker still, since one PDU for both switches creates a shared distribution point with no battery backup.
Maximum uptime caveat For true design redundancy, each switch would ideally use a separate UPS on a separate circuit, and the UPSs would be monitored and tested. The question’s options do not offer that perfect design. Among A–D, D is the only one that keeps the switches powered during the outage. The supplied comments echo this: a PDU distributes electricity, while a UPS provides emergency battery backup. Therefore the correct answer is D.
Official Reference
https://www.comptia.org/certifications/network
This link opens the official vendor documentation in a new tab.
Exam Strategy
When a question asks about uptime during an outage, separate power-distribution devices from power-backup devices. A PDU, circuit, or outlet strip only moves electricity; a UPS or generator supplies it when the utility feed drops. Also watch for single points of failure: if an option places both switches on one UPS, it may still beat options with no battery, but the ideal design is separate UPSs on separate circuits. Eliminate answers that address breaker trips rather than a full outage.
Frequently Asked Questions
Does plugging each switch into a different PDU provide battery backup during a power outage?
Why are separate circuits not the best answer for a power outage?
Is one UPS for both switches enough for maximum uptime?
Community Votes
100% of anonymous learners picked answer D. Votes are pick records left by other test-takers — they are not the verified answer.
Discussion 2 contributions
Compiled from public community threads and reader submissions, lightly edited for clarity. Handles and vote tallies are shown as recorded, and comments reflect the views of individual contributors.
From public community threads 2
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Provost 👍 1 Answered DCorrect answer: D — connect each switch to a separate UPS. The option’s wording is awkward, but that appears to be its intent. A UPS (Uninterruptible Power Supply) provides battery power during an outage, keeping the switches running. - A. Same PDU: A Power Distribution Unit distributes electricity but ordinarily provides no battery backup. - B. Different circuits: Protects against one circuit failing, but not a building-wide outage. - C. Different PDUs: Provides distribution redundancy, but no backup power by itself. Power outage + continued uptime → UPS.
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ERB14 👍 1 Answered DPlugging both switches into a different UPS: An Uninterruptible Power Supply (UPS) provides emergency battery backup power when utility power fails. Connecting each switch to a separate/different UPS ensures that if a power outage occurs or if one UPS fails, battery power keeps the switches running, providing maximum redundancy and uptime.
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