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How to Choose a UPS System to Meet Your Power Requirements

Updated: Feb 23, 2020

The recent load shedding period once again reminded South Africans of the need for backup or alternative power supply. Electronic equipment is sensitive to current surges and outages. Uninterrupted power supply (UPS) is the first line of defence against the effects of power interruptions. Knowing how to choose a UPS system that’s right for your particular needs is thus the first step towards countering the electricity interruption blues.

Use the guidelines below on how to choose a UPS system to make sure you select a system that meets your supply requirements. First, let’s get a better understanding of what the system involves and why you need one.

Essential battery backup power

At its core, the system provides backup power long enough to allow for proper switching off or shutting down of televisions, computers, console games and other electronic equipment when a cut in electricity supply is experienced. The two main components are the battery and surge protector. The latter serves to protect all the connected equipment from the effects of sudden cut or abnormalities in voltage supply that can cause damage to the devices.

Why you need the solution

At the onset of a power outage, the system provides for a controlled switch-over ensuring ongoing power supply. This is also why it is important to know how to choose the best UPS system for your particular needs since the battery life depends on the particular system and power usage. It should give sufficient time for controlled shutting down of the most delicate devices.

Types available

With three categories from which to choose, how do you know which system is best for your needs? Each category is based on the nature of power supply protection required.

Determine which power problems to address

Blackout – occurs when due to load shedding or another electricity supply interruption where all power to appliances is cut. It can be short or long period.

Line noise – disruption of the circuit action as the result of interferences in the current.

Variance in frequency – fluctuation in power as the result of generator power supply.

Brownout – The electricity provider may lower voltage to reduce strain on the grid in an effort to avoid complete grid failure.

Surge – an intense spike in supply, as can be caused by lightning strike This destroy important components in electronics. The voltage and current surge or spike can fry the circuit board of the particular electronic device.

Over voltage – higher voltage than normal, lower in voltage than a surge, but longer than a spike.

Voltage sag – short under-supply of voltage. Unlike a brownout, it is short and sudden.

Harmonic distortion – deviation of the desired electrical current.

Select a system to address specific problems

Make a list of the most common problems that you want to address.

Double conversion addresses:

BlackoutSurgeBrownoutLine noiseFrequency varianceOver voltageVoltage sag Harmonic distortion

Line interactive addresses:

Over voltage Under voltageBrownoutBlackoutSurge

Standby addresses:

Brownout BlackoutSurge

What size to choose?

The system must be able to support all the equipment connected to it. Check the UPS capacity measured in watts. To determine capacity needs, calculate the load. The latter refers to the combined power off all the appliances to be supported simultaneously.

Determine load

Choose the right system by listing the devices and the total watts required by each. The watts required will be listed somewhere on the device or in the user manual.

Determine outlet requirements

Choose a UPS with sufficient outlets to handle the specific number of devices that you want to connect.

Determine supply period requirements

After having determined size, problems to address, and number of outlets required, determine the battery time requirements. Do you want enough time to shut down connected equipment or do you want to keep specific equipment running during the power problem period?

To determine the runtime requirement, consider the period that the batteries can support the connected equipment. Determine how many minutes you need to safely shut-down the connected devices in order of wattage (load). You want a broad range of run times to ensure you can have more UPS systems to choose from. The range is the minimum time needed and the maximum time you need the system to provide power.

Determine whether you need sine wave output

Electricity is supplied in sine wave, the same as supplied by the UPS in the usual operation mode. In battery mode, the system produces sine wave or a simulated sine wave. With the simulated mode a power gap exists at each cycle. Some equipment cannot handle the gaps. The simulated sine wave has a square profile whereas the regular sine wave current is similar to smooth up and down hill movements.


You can choose between desktop, tower or rack-mount types, depending on where the system will be placed and used. The desktop type can be placed underneath a workspace whereas the tower with its attractive design can be placed on top of the desk. The rack-mount type is best-suited for placement a server room.

Get in touch for professional help to choose a UPS system from our product profile, ensuring your uninterrupted power supply needs can be met.

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