Cut down PC shutdowns

UPS and running
The UPS fits in between the wall socket and a PC – most UPS boxes have several sockets, so you should be able to run other devices, such as a printer, from it, too.

During normal use, the UPS charges its battery and monitors the power from the mains, which it passes through to your PC. If the voltage drops, it very quickly (typically within a few milliseconds) switches circuits, so AC power is supplied to your PC from its battery, through the inverter. It does this so quickly that the PC is unaffected.

When the power is restored to its normal level, the UPS switches back to its monitoring status and recharges its battery for the next time. Obviously, when it’s running, the UPS battery quickly discharges, typically in 15 to 30 minutes. The word ‘uninterruptible’ is therefore a bit of a misnomer – it simply buys a little time. That time can be used to save work and shut down your PC properly.

In fact, many UPS boxes come with software that does this automatically, saving open documents to a temporary folder so you don’t lose work should there be a power cut while you’re making a coffee.

UPS boxes start from around £40 and rise in price depending on the sophistication of their power sensing the level of the power they can supply. For example, you’ll pay a lot more for a UPS that can run several PCs on a network, than for one that handles a single machine.

To work out which UPS rating will suit, you need to find out how much power your PC uses. This sounds a little complicated on the face of it, but is in fact a case of using basic maths skills.

UPS manufacturers tend to rate their devices in VA, which is like a watt, but not the same. The watt takes into account that the power is AC and therefore the voltage and current are not in the same ‘phase’.

We don’t need to go into the technicalities, but you need to realise that when a UPS is rated at, for example, 200VA, it doesn’t mean 200W. The conversion, known as the ‘power factor’, for a PC is around 1.4, so you would need a 280VA UPS to cover a 200W load. We’ll explain how to do a rough calculation of your computer’s VA rating below.

Find out how many watts your PC consumes and how much your monitor uses, too. This information is usually included in any specification sheets that came with the computer, or is stamped on a label on the side of the power unit inside your computer. If your PC is a popular brand, try looking up the specifications on the manufacturer’s website.

Multiply the wattage by 1.4 and you should have calculated the approximate VA.

Notebook PCs aren’t as dependent on the mains supply as desktops. Because they have batteries built in, notebooks will automatically start to run from the battery if the mains power disappears. In effect, they have a UPS built in, and one which will typically power them for several hours.

The two most popular manufacturers of UPS units are APC and Belkin and UPS boxes suitable for domestic and small business uses are available from most online computer stores, such as Dabs, Ebuyer and Misco.

Power trip
The easiest way to assess whether you need to invest in a UPS is to fantasise about losing the most important thing on your PC. Is it the manuscript to your first novel, or the first three stages of Luxor?

Only you can decide what it would mean to lose it, but if it would involve a lot of hard work to put right, it might be worth paying £70-80 to avoid. And there’s really little argument about a surge protector. At £25 or so, they’re cheap protection for expensive kit.

Wise though it is to back up, physical protection saves your precious information and the computer holding it.

Zapped!
It’s not just loss of power you need to guard against, but too much. Power surges and spikes can destroy electrical equipment, and computers are among the most costly to repair or replace. A surge suppressor built into a multi-way power block – four or six mains outlets – can guard against this and most come with substantial insurance guarantees.

It’s not just mains that needs protecting from electrical surges. They can just as easily come through the phone wires. We know at least one village where half a dozen people all lost their broadband modems when lightning struck near one of the telephone poles and induced a spike, which zapped them. Some of the multi-way blocks also include phone surge suppressors.