Correct option is D
Laser printers draw very high power, especially during fuser warm-up and printing bursts, causing large inrush and peak currents.
These surges can overload a typical UPS, shorten its battery life, and trigger overload faults or voltage drops that affect other protected devices.
Manufacturers commonly advise plugging laser printers directly into a wall outlet (often on a separate circuit) rather than into the battery-backed UPS outlets.
In contrast, low-power IT gear (PCs, servers, switches, routers, NAS, monitors) is appropriate for UPS protection.
If surge protection is desired, some UPS units offer “surge-only” outlets for printers—no battery backup.
Hence, laser printers are usually not connected to a UPS’s battery-backed outputs.
Manufacturers commonly advise plugging laser printers directly into a wall outlet (often on a separate circuit) rather than into the battery-backed UPS outlets.
In contrast, low-power IT gear (PCs, servers, switches, routers, NAS, monitors) is appropriate for UPS protection.
If surge protection is desired, some UPS units offer “surge-only” outlets for printers—no battery backup.
Hence, laser printers are usually not connected to a UPS’s battery-backed outputs.
Important Key Points
- High Peak Draw: The fuser heater in laser printers can momentarily exceed the UPS’s rated VA/W, causing overload.
- Battery Stress: Large current spikes rapidly deplete/age UPS batteries, reducing runtime for critical devices.
- Power Quality Risk: Printer surges can cause voltage dips, rebooting other devices on the UPS.
- Recommended Practice: Plug laser printers into wall power; use a separate surge protector or surge-only UPS outlets if needed.
- UPS Loads to Include: PCs, servers, networking equipment, and storage—devices that benefit from ride-through and safe shutdown.
- Exception Cases: Only very large, line-interactive/online UPS systems sized for printers should carry them—and that’s uncommon in offices.
Knowledge Booster
- (a) KVM switch: Very low power (typically a few watts); safe and common to place on a UPS to maintain console access during outages.
- (b) External mouse: Negligible power via USB from a UPS-protected PC; no issue for UPS capacity.
- (c) USB video camera: Usually low power (USB-powered), rarely stresses a UPS; acceptable if the host system is on UPS.
- Why printers differ: Inkjet printers draw less than lasers but still not mission-critical; laser printers’ heater/fuser causes the problematic high inrush and cyclical power spikes.
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