Is it permissible to connect a laser printer to a surge-only outlet through a UPS?
Is it permissible to connect a laser printer to a surge-only outlet through a UPS?
I recently purchased a laser printer and found information suggesting they shouldn't use a UPS. However, UPS units offer both surge and battery-powered as well as surge-only connections. Can I safely connect my printer to a surge-only outlet on the UPS?
My laser printers are connected to battery-backed outlets since I have a lot of extra UPS capacity from my solar system.
The initial power consumption of a laser printer can temporarily exceed twice the maximum rating shown on its label, which may trigger an immediate UPS shutdown if its power supply is suddenly overwhelmed—even though the line power remains stable.
This situation becomes significant when the printer’s label indicates 700-1000 watts, as there’s often a safe operating range between that and the alarm threshold.
Occasionally, the UPS overload warning sounds without causing an immediate shutdown, which can be frustrating each time you print.
I also use my furnace in battery-backed outlets. Induction motors draw much higher inrush currents than those of laser printers; for a brief moment, they can exceed the motor’s rating by up to ten times.
If the UPS runs on battery during motor startup, it’s essential to have extra capacity available. That’s why appliances like air conditioners or refrigerators—whose power needs vary—are better suited when drawing from a solar bank. These devices ramp up gradually, avoiding large inrush currents and making them more compatible with generators or UPS systems.
If you don’t need to print during an outage, surge-only outlets should suffice. I’ve never heard of a laser printer being damaged by a power interruption mid-print job, so the main risk is usually wasting paper.
However, if inkjet heads stay unparked for too long, they can become clogged.
The design varies by manufacturer. IsoBar surge protectors are constructed similarly to tanks, while many power strips are not.
I have related questions about UPS systems. My 2023 Mac mini outputs up to 150 watts. My old 27-inch Dell monitor draws 20 watts, making the total 170 watts. I own a Cyberpower 1,000 VA compact UPS with 12 outlets—6 surge and 6 battery-only. I don’t need all 12, so I’m considering upgrading to a smaller compact line-interactive UPS. The fewest outlets I’ve seen are six each. Should I upgrade to a higher wattage? A 170-watt unit wouldn’t last long. My monitor is failing and would likely draw more than 20 watts. A newer Mac mini would probably exceed 150 watts. So, is that acceptable? In other words, doubling the load to 340 watts? I want to stay under 1,000 VA. On the APC website, some UPS models use non-replaceable batteries—what does that mean?
I own a Brother MPC-L3720CDW multi-function color laser printer that I purchased about a year ago. It's a good printer, but Brother clearly warns against connecting it to any outlet on a UPS. I forgot this advice and connected it to both the battery-protected outlets and the surge-only outlets of my APC BR1500MS2 UPS. In both cases, the UPS began making noises when I attempted to print with the printer connected. After searching online, I discovered that Brother explicitly states the printer should never be connected to a UPS unit. Once I switched it to a regular wall outlet, everything worked fine. Other printers might handle a UPS, but not this Brother model. This is just my experience. YMMV.
Regards,
Phil