A UPS (Uninterrupted Power Supply) device is normally bought as an afterthought, if any money is left after buying the PCs. But a UPS not only keeps work going in case of a power- cut, but also protects machines as an advanced surge protector and a device that provides clean power supply essential for a PC. All this comes at just a small price, but ensures that your valuable investment stays safe. Calculate your power needs. This is the tricky part. No matter which UPS (Uninterrupted Power Supply) company you approach, it would want to sell a high-end solution for your home office or small business, while you will be better off with a solution that is much more attuned to your needs. Before purchasing a UPS you need to consider your PC’s power consumption.

A regular Pentium 4 computer with a generic 17-inch monitor consumes close to 400W or 560VA (Volt/amps) of power. We will assume this consumption if the configuration has a single hard drive, 256 MB of RAM and a Combo drive. No printers or other external power consuming equipment have been considered. In such a situation, it would be wise to go in for UPS with 600VA rating. Also, a UPS falters if the load on it exceeds its rating. So if a 500VA load is applied on to a UPS that provides 500VA of power, you will end up getting only five minutes of back up time. Based on this thumb rule, calculate the VA rating for each device you want connected to the UPS.

Here’s an easy way of calculating the VA rating for each device that you have: 1. List all equipment you want connected to the UPS— monitors, hubs, external hard drives, in fact anything that requires power and needs protection. 2. If any device has a power rating given in watts, take that figure and multiply by 1.4. This gives you the device’s VA rating. 3. Check the amps and volts ratings of the devices you have listed. To get a VA rating, multiply the amps by the volts. 4. Add the VA ratings of all your devices to get a grand total. 5. Multiply this total by 1.2 if you want to factor in one more device later. 6. Make sure that whatever type of UPS you opt for, your VA total should not exceed the VA rating of the UPS. It is always recommended to buy a UPS with a higher VA rating than your cumulative VA rating.

Before you set up…

SoHo (Small Office Home Office) businessmen would typically face two scenarios when it comes to UPS implementation— whether to connect one big UPS to centrally control all PCs at the same time, or to have individual UPS for every PC. Why only PCs? Because connecting a printer (especially if it is a laser printer) to a battery output socket on the UPS will cause considerable power drain, which could instead be used for another PC. Based on our power calculation earlier, a modest eight-person SoHo outfit would require at least a 5kVA UPS considering eight Pentium 4 PCs with 17-inch monitors. This done, check the UPS type you consider to be the best option in your budget. We would recommend spending a little more and get a good UPS rather than go for an ‘in-the-budget’ solution.

For a single PC home solution with a printer and scanner, considered with a backup time of around 10 minutes, you will need to opt for a UPS that provides at least 700VA of power and will vary for the different options that we mentioned above.

And some thoughts for the road… SoHo or home users can easily opt for solutions mentioned above. There are several UPS brands available in the market and quite a few local brands have earned themselves a good reputation. Nevertheless, make sure you go through the product brochure and take some time to understand the ups and downs of the product. What may look good at first sight, may turn out to be bad oversight on your part. No matter what option you pick—centralised or decentralised—depending on your budget and the priority and importance that you assign to your machines, make an investment that will last you through the years.

Before you sign the cheque…

- Check for the warranty offered. Some UPS manufacturers provide model specific warranties. - Pay attention to the manufacturer's support agreement. Do they have a replacement policy? Do they have trained support personnel? What happens in case the UPS goes kaput? Do they have a policy of providing standby UPS machines? Ask your vendor these questions before you buy. - What software do you get to monitor the UPS? How effective is it? Does it automatically shut down PCs if it is low on battery? Does it continuously monitor and give you a status report of voltage conditions and situations like brownouts? Questions like these would put to rest the doubts about the software solution provided with the UPS. - The best possible situation is to test the UPS at your location. Ask the manufacturer to arrange for a demo that will simulate your work conditions and check if the claims of the manufacturer match the performance of the UPS.