How to Size an Uninterruptable Power Supply (UPS)

Understanding UPS Systems

What is an Uninterruptible Power Supply (UPS)?

A UPS (Uninterruptible Power Supply) provides backup power to equipment during a power outage, allowing systems to shut down safely. It helps prevent business disruptions and data loss caused by unexpected power failures.

What are the Different Types of UPS Systems?

UPS systems come in three main types: Standby, Line-Interactive, and Online. Each type offers different levels of protection based on your power requirements. You can learn more about each type and its benefits in our UPS Help Guide.

Why Do I Need a UPS System?

UPS systems are essential for protecting critical equipment from power-related issues like outages and voltage fluctuations. Different industries rely heavily on UPS systems to ensure operations aren’t interrupted—whether its keeping medical equipment running in hospitals, maintaining government services during emergencies, or protecting IT infrastructure in schools and universities. In any field, a UPS system helps prevent data loss, equipment damage, and downtime during unexpected power disruptions.

How are UPS Systems Sized?

UPS systems are typically sized using kilowatts (kW) or kilovolt-amperes (kVA). To properly size your UPS, there are two main questions to consider:

1. How much power is required to support my connected equipment? – This is the system’s capacity.
2. How long will the UPS need to support my equipment during an outage? – This is the runtime.

Sizing Your UPS by Capacity and Runtime

How Much Load Capacity does my UPS System Need?

1. Make a list of all the electronic devices you’ll be connecting to the UPS.
2. List the wattage (W) or volt-ampere (VA) for each device. These ratings can usually be found on the label on the back of the device.
3. Add up all your devices’ wattage or VA ratings to find the total load.
4. Increase the total load by 20-25% to account for power spikes and future growth. For example, if your total load is 2000W, adding 20% (400W) results in a total of 2400W.
5. Keep the load within 75-80% of the UPS’s capacity. For instance, running 900 watts on a 1kVA UPS means it’s operating at 100% load, which can risk overloading. To avoid this, aim for 75-80% capacity—450 watts on the 1kVA UPS is a safer, more efficient load at 50%.

How Long will the UPS Need to Support Your Equipment?

When choosing a UPS, it’s important to consider how long you want it to power your devices during an outage. Are you looking to safely shut down critical servers, keep your network infrastructure operational, or maintain essential equipment like security systems during an outage? This is where runtime becomes crucial.

What is Runtime?

Runtime refers to how long a UPS can keep your devices powered during a blackout. The minimum runtime is generally the time required for a safe shutdown. If you need to keep things running longer (such as during an extended outage), you’ll need a UPS with a longer runtime.

The runtime depends on the wattage load connected. The higher the load, the shorter the runtime, and vice versa.

How to Determine Your UPS Runtime

To choose the right runtime, start by considering how long you need for a safe shutdown. From there, you can create a range of acceptable runtimes, with more options available the broader the range.

For example:

• A 1kVA UPS (900 watts) from N1 Critical Technologies gives you 11 minutes of runtime at full load.
• A 2kVA UPS running the same 900-watt load would give 24 minutes at 50% load.
• A 3kVA UPS would offer more than 30 minutes at a lower load of 33%.

Other Important Considerations

Once you’ve figured out your capacity and runtime requirements, consider the following additional factors to choose the best UPS for your business, industry, and needs.

Number of Outlets

Ensure the UPS has enough outlets for all the devices you plan to connect. Once you've calculated your load, count the number of power cords, and choose a UPS that can accommodate them.

UPS Size

The physical size of the UPS is crucial, especially for businesses with limited space. There are three primary form factors:

• Compact UPS
• Tower UPS
• Rack-mountable UPS

Maintenance and Support

Review the warranty, maintenance options, and customer support available for the UPS system. This will ensure you're covered in case of any issues. We stand alone in the UPS industry as the sole providers of quality products with a 10-year replacement warranty on our batteries and all electronics.

Choosing the Right UPS for Your Needs

Selecting the right UPS is critical for maintaining business continuity during power disruptions. If you need assistance finding the perfect UPS for your business, reach out to N1C. Our experts are ready to help you choose the ideal system based on your unique requirements.