UPS Systems 101: How Uninterruptible Power Supply Systems Work and Why They’re Important

UPS Systems 101:
How Uninterruptible Power Supply Systems Work and Why They’re Important

Data privacy and security are important topics these days, but what about data preservation? Have you ever wondered how critical data is kept intact during a blackout? The answer is an uninterruptible power supply, or UPS, system. You’ve probably seen one and didn’t know what it was. It’s a crucial part of modern data management, but it’s basically just an expensive battery.


Now, obviously calling this important piece of equipment just an expensive battery is an oversimplification. But the principle is the same.

Batteries come in all shapes and sizes and power anything from children’s toys to cars. They’re such an integral part of modern life that you might be surprised to learn they’ve been around since before the light bulb was invented. According to HowStuffWorks, one of the earliest known forms of electrical power storage was invented in 1800 by Alessandro Volta. And yes, the “volt” is named after him.

While the technology has improved over the years, the core principle is essentially unchanged from his original 19th century concept: with the right mix of metals and chemicals, electricity can be stored and used later.

So why is it important to understand the history of batteries, and what does that have to do with data preservation? After all, a battery can’t store information.


Most organizations these days have some form of a data server that they use to run their operation. Whether it’s a server they own themselves or server space they pay someone else to use, information has to be stored somewhere. Whether it’s a bank branch or corporate headquarters that keeps their data on-site, or a grocery or department story that keeps data at a centralized corporate location, it needs a home.

Fun fact: “cloud storage” is just paying someone else to use their server and access your info over the Internet.

So a server, then, is an important part of a secure network. There are various levels of servers depending on the needs of the organization. It doesn’t have its own power supply, though, which can be a serious weak point in the event of a blackout. Since a server needs consistent power in order to maintain the flow of data, power loss could result in the loss of critical information for that organization. At a minimum, employees or clients won’t be able to access it. But in the worst case scenario, it could actually erase the data altogether.

That’s where a UPS system comes in. It’s connected to and charged by the server’s normal power supply. When a loss of power is detected, the UPS system switches over to battery power and keeps the server up and running long enough to either restore normal power or back up the data before the battery dies. This is why they’re so expensive – they’re built to be a last line of defense before a server goes down. They can cost anywhere from a few hundred dollars for home use to upwards of $20,000 for enterprise infrastructure equipment, depending on the type of power it uses, its size, and the battery capacity.

They come in many shapes and sizes, all with the same main components. There’s a power input, internal batteries, power output, a sensor to monitor for power loss, and an internal switch between the normal power supply and the batteries.

For basic UPS systems that use standard wall outlets, anyone can install them by following the manufacturer’s provided instructions. But for commercial systems like those in most commercial server rooms, power will likely need to be routed to the location along with a specialized outlet to connect it. For that, you’ll need to call a licensed electrician.


If power supply is normal, then the UPS system is sitting on standby and not doing much. It allows electricity to pass through directly to the server and maintains the charge in its batteries. The only time it is actively working is when there’s a power failure. Then the sensor monitoring power flow triggers the internal switch and power is instantaneously switched over to the battery supply. This will typically last about 90 minutes, giving you enough time to diagnose the problem and secure the data – either by restoring power or backing up the server. Every UPS system is different so make sure you know which one you need before installing it. Your electrician can help you make that call.

We know this is an expensive piece of equipment – especially for something that you hope you’ll never have to use. But like a fire extinguisher or a natural disaster kit, you’ll be glad you have one if you ever do need it. And just like those things, a UPS system is important to maintain so you know you can rely on it when the time comes.

For enterprise level systems, maintenance includes visual inspection of the batteries and housing to look for damage or deterioration and swapping out old batteries on a 3-5 year schedule depending on the manufacturer’s recommendation. These larger systems can have components serviced and repaired, extending their effective lifetime and making the investment last longer. Smaller UPS systems are typically replaced rather than maintained. Damaged components often can’t be repaired, so the entire unit must be exchanged for a new one. To perform any kind of UPS maintenance, the data must be backed up so the power can be turned off to service the system.

And that’s pretty much it. An expensive, modern version of a technology that’s been around since the 1800s is the safety net that prevents critical data loss. Thank you, Mr. Volta.


Lately, a relative of the UPS system has started making its way into our homes. Home power storage, like Tesla’s Powerwall, works on the same principles as a UPS system, but has a couple of key differences. The home batteries store power generated by solar panels and they’re meant to be cycled repeatedly rather than hold a charge in case of an emergency.

They operate things like home appliances and lighting rather than data servers, but they work the same way as a UPS. When the power supply is flowing, solar energy in this case, it simultaneously charges the batteries and passes power through to the home. When the power supply is gone, such as at night or on a cloudy day, the batteries kick in and keep the home up and running – typically in conjunction with drawing power from the utility grid.

AAA Facility Services is a C-10 licensed electrician. Contact us to ask about whether a UPS system could help your business.

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