Power quality and protection – Which device protects against line deficiencies (sags, brownouts, outages)?

Introduction / Context:
Computers and networking gear are sensitive to line conditions. “Line deficiencies” include sags, brownouts, frequency anomalies, and full outages. Choosing the correct protection device prevents data loss and hardware damage.

Given Data / Assumptions:

• Goal: protect equipment from undervoltage and outages, not just overvoltage spikes.
• Office/home environment with standard AC mains power.
• Typical IT loads (PCs, servers, modems/routers).

Concept / Approach:

A surge protector primarily clamps transient overvoltages (spikes) using MOVs or similar components. It does not supply power during an outage and does little for sustained sags. By contrast, a UPS contains batteries and power conversion stages to maintain output voltage during deficiencies, surviving outages for minutes and bridging to shutdown or generator power.

Step-by-Step Solution:

Verification / Alternative check:

Line-interactive and online double-conversion UPS models actively regulate output across a range of input voltages and ride through outages. Specifications list transfer times or continuous conversion.

Why Other Options Are Wrong:

Surge protectors address spikes only. A logic probe is a digital diagnostic tool, and a capacitor across mains is unsafe and ineffective for sags/outages.

Common Pitfalls:

Assuming a surge strip equals power protection; undersizing UPS capacity; ignoring battery maintenance leading to failed protection when needed.

Final Answer:

UPS (Uninterruptible Power Supply).