Protecting your business equipment from Kenyan power

A surge takes out a computer, a till or a router, and the claim is refused because the warranty does not cover damage from the mains. This happens constantly and it is almost entirely preventable.

## The three separate problems

They are different and they need different answers.

A **surge** is a brief spike, often when the power comes back after an outage. It kills equipment outright.

**Sags and brownouts** are the voltage dropping below what the equipment expects. This does not kill anything today; it shortens the life of the power supply over months, and the failure looks like bad luck when it comes.

An **outage** is the power going off. The damage there is not to the hardware but to whatever was half-written when it went.

## What to buy for each

For surges, a surge protector on anything valuable. This is the cheapest insurance in the building and most businesses skip it. It is a consumable: it absorbs a large surge and is spent, so replace it after a serious one rather than assuming it still works.

For sags, an AVR, or a UPS with AVR built in, which is most of them. It holds the output steady while the input wanders.

For outages, a UPS, but understand what it is for. It is not a generator. Fifteen to twenty minutes on a typical unit is enough to finish the transaction and shut down properly, and that is the whole job. Trading through a long outage is a generator or an inverter, which is a different purchase and a different budget.

## What to put on a UPS, in order

Anything that holds data: the server, the till, the computer the books are on. A database interrupted mid-write is the expensive failure.

Then the router and the switch. A computer that stays up while the network dies is not much use, and this costs very little.

Then the desks, if the budget reaches. This is comfort rather than protection.

Do not put a laser printer on a UPS. It draws far more than the unit expects when it warms up and will trip it.

## Which UPS

For a till or a desktop, an ordinary line-interactive unit is right.

For a server, or anything with an active PFC power supply, buy a pure sine wave unit. The stepped waveform a cheaper UPS produces can be refused outright by that kind of supply, and you will find out at the worst moment.

## Earthing, and who checks it

A surge protector works by sending excess voltage to earth. If the socket it is plugged into is not properly earthed, it has nowhere to send it, and the protector gives you a feeling of safety and very little else. Older buildings and hurried extensions are where this most often goes wrong.

An electrician can test the earthing in an afternoon, and it is worth doing before you spend money on equipment that depends on it. Ask them to check that the sockets your computers, tills and network equipment use are on a circuit that is not shared with a kettle, a fridge or a welding shop next door.

## The part everybody forgets

The battery is a consumable. Two to three years in Kenyan conditions, less where the power is bad. A UPS with a dead battery beeps and does nothing, and plenty of them sit under desks in exactly that state.

Test it twice a year: pull the plug and see how long things stay up. Write the date on the unit. Replacing a battery costs a fraction of replacing the UPS, and a great deal less than the outage it fails to cover.