Whatever stage Eskom’s schedule is on this week, South African businesses still lose power — to load shedding when it returns, and to cable theft, municipal faults, storms and maintenance that never appear on a schedule. For a business that runs on computers, the cost is not the two hours in the dark. It is the corrupted file, the dead router, the tills that will not take a card, and the server that never came back up properly. This guide covers what power cuts actually do to business IT, how to size backup power for your own equipment with a planner, the real differences between a UPS, an inverter, DC backup and a generator, how to protect servers, fibre, card machines and cameras, and the safety and compliance points that get skipped.
The Short Answer
Do not try to back up your whole office. Protect what keeps you online and what can be damaged, in this order: your internet connection first (router, ONT and access points, which need very little power), then servers and storage with automatic safe shutdown, then tills and card machines, then desk PCs — where laptops are a free battery. Use a line-interactive UPS for short cuts and surges, DC backup for small loads that must run for hours, and an inverter with a battery only where you genuinely need long runtimes on bigger loads. Get a registered electrician for anything fixed to the building, and test the whole setup by pulling the plug.
What Power Cuts Actually Do to Business IT
The obvious damage is that everything switches off. The expensive damage is what happens around the switching off.
- Corrupted files and databases. A cut in the middle of a save leaves a half-written file. On a server, it can leave a database or a disk array in an inconsistent state that takes hours to repair, or a restore from backup.
- Stressed hardware. Repeated hard shutdowns are tough on drives and power supplies. Failures tend to arrive weeks later and get blamed on age.
- The surge when power returns. Restoration is often rougher than the cut. A spike or a flicker as the supply comes back is a common way for routers, power supplies and monitors to die.
- Being offline while you have power. Fibre street equipment and cell towers run on batteries that long or back-to-back outages can drain, so your building can have electricity and no internet, or the other way round.
- Lost sales. Tills, card machines, online orders and bookings all stop. Our guide to NFC digital menus for restaurants and takeaways makes the point in one line: the tag needs no power, but the page it opens needs signal.
Data damage in particular is worth taking seriously, because the worst outcome is not an inconvenience but a recovery job. Our guide to data recovery covers what that involves.
Work Out What Actually Needs Power
The most common mistake in backup power is buying a system sized for the whole office, then discovering it needs a battery bank the size of a fridge. The size of a backup system is driven almost entirely by what you plug into it, and by how long you want it to last. Try it on your own equipment.
Two things are worth noticing. First, watts add up quickly: desktop PCs and servers dominate the total, while the whole connectivity stack — ONT, router, switch and access point — draws less than a single desktop. That is why the last box in the planner matters. Keeping only your connectivity up for a whole load-shedding block takes a small fraction of the battery, and it is often the difference between “we can still take orders on our phones” and “we are dark”.
Second, battery chemistry moves the answer a lot. The same load and the same runtime needs far less nominal battery energy on lithium than on lead-acid, because you can use most of a lithium battery each cycle and only about half of a lead-acid one without shortening its life. Try switching the battery type and watch the numbers change.
UPS, Inverter, DC Backup or Generator: Which Do You Need?
These get used interchangeably, and they are not the same thing.
Line-interactive and online UPS
A UPS is designed to switch to battery almost instantly and to clean up the power feeding your equipment. There are three broad kinds. Standby units are the cheapest and offer the least conditioning. Line-interactive units, the sensible choice for most offices, regulate voltage without using the battery and switch over within milliseconds. Online units keep the equipment permanently powered through the battery circuit, so there is no switchover at all; they cost more and use more electricity, and suit servers and other equipment that must never blink.
A standard plug-in UPS has a small sealed battery. Expect something like ten to twenty minutes for a single desktop PC and monitor. That is not a way to work through a load-shedding block; it is a way to save your work and shut down cleanly.
DC UPS and power banks
Most routers, ONTs and many access points run on low-voltage DC power. A DC UPS or a compact lithium power bank feeds them straight from a battery, without converting to mains and back, which is far more efficient. For small loads that must run for hours — your internet connection — this is by far the cheapest way to stay online. Check each device’s input voltage and connector first; a mismatch can destroy equipment.
Inverter and battery
An inverter turns stored battery energy into mains power for hours rather than minutes. It is the answer when you need longer runtimes on bigger loads, such as tills, PCs and cameras together. Two cautions: cheaper inverters can switch over slowly enough that a desktop PC reboots, so many businesses put a small UPS behind the inverter to bridge the gap; and IT equipment should run on a pure sine wave inverter, because cheaper modified sine wave units can make power supplies run hot and upset UPS units.
Generators and solar hybrids
Above a few kilowatts, or when the battery you would need becomes enormous, the answer is a generator with an automatic transfer switch or a solar-hybrid system. These are designed installations, not products you buy off a shelf, and they belong with a specialist. The cheapest way to make one smaller is to cut the load first.
Lead-Acid or Lithium?
- Lead-acid (including the sealed batteries inside most UPS units) is cheaper upfront, widely available and familiar. You can only use about half its capacity each cycle without shortening its life, it is heavy, and it typically needs replacing every few years.
- Lithium iron phosphate (LiFePO4) costs more upfront, but lets you use about 90% of the capacity, lasts for several thousand charge cycles, is much lighter and holds its voltage better under load. Where the system cycles regularly, the higher price often pays for itself over the battery’s life.
As a rough rule, lithium makes sense wherever backup power is used often, and lead-acid where cuts are rare and the budget is tight. Either way, ask for the usable capacity and the number of cycles, not just the label figure.
Protect the Network First
Your connection is the cheapest thing to keep alive and the most valuable thing to keep alive, because so much of a modern business now lives in the cloud.
- Put the ONT, router, firewall, switch and at least one access point on backup, all of them. The one you forget is the one that breaks the chain.
- Check what powers your access points. Many are powered over the network cable (PoE), so the switch feeding them needs backup as well.
- Add a cellular failover. A 4G or 5G backup connection takes over when your fibre fails. Choose a network different from the one your staff use for their phones, and remember that cell towers have batteries too.
- Keep backup power off your network’s critical path where you can. A small DC unit on the connectivity kit keeps working even if your main backup system is under strain.
Good network design also makes power protection easier — our guide to network security and WiFi setup covers the equipment and layout that makes it simpler to back up only what matters.
Servers and NAS: Shut Down Gracefully
A server that loses power suddenly can come back damaged. The purpose of a UPS on a server is not to keep it running forever; it is to give it time to shut itself down properly.
- Connect the UPS to the server by USB or network, and install its shutdown software.
- Set the shutdown to trigger with margin. Start the shutdown well before the battery is empty, with time for every service to stop.
- Include your storage and virtual machines in the sequence, not just the main server.
- Test it. Pull the plug and watch it shut down cleanly, then power back on and check that everything comes up.
- Keep a tested backup regardless. A UPS reduces the chance of a bad shutdown; it does not replace a backup. Our guides to server management and cloud backup cover both.
Tills, Card Machines and Cameras
- Tills and point-of-sale terminals should be on backup along with their router or switch, or they cannot reach the payment network.
- Card machines usually have a battery, but many depend on your network or a mobile connection to process a payment. Confirm what yours does when the connection drops.
- Cameras and recorders are easy to forget until you need the footage from the night the power was out. A recorder that shuts down badly can corrupt its own storage.
- Keep laser printers off your UPS. They draw large surges that can overload the unit. Plug them into a surge-protected socket that is not battery-backed.
Surges: The Danger After the Lights Come Back
Even a well-backed-up business can lose equipment to what happens when power returns or when a storm hits.
- Put a UPS or a good surge protector between the wall and expensive equipment. Plug a UPS straight into the wall, not into a power strip.
- Switch off or unplug big equipment when the lights go out, and give it a few minutes after they return before switching it on again. That skips the roughest moment of restoration.
- Remember that surge protectors wear out. The part that absorbs spikes degrades every time it takes one, so replace them every few years and after a nearby lightning strike.
- Check the earthing. Surge protection only works if the building is properly earthed, which is another job for a registered electrician.
- Do not forget the network cable and the aerial. Surges can travel in through any cable that leaves the building.
Move What You Can Off Your Own Power
The best way to survive a power cut is to depend less on the office being switched on.
- Move email, files and applications to the cloud. With Microsoft 365, staff can work from anywhere with a laptop and a connection, and the business no longer stops when the office server does.
- Back up to the cloud, so recovery does not depend on a device that might not survive the cut.
- Choose laptops over desktops where you can. A laptop is a free UPS, and it draws a fraction of what a desktop and monitor do — which changes your planner numbers dramatically. Our guide to desktop support covers the trade-offs.
- Use cloud telephony or mobile numbers, so your phones do not depend on a desk-phone system that needs mains power.
Safety and Compliance: The Part People Skip
- Use a registered electrician for anything fixed to the building. Installing inverters, battery banks and changeover switches is electrical work, and in South Africa a fixed installation should come with a Certificate of Compliance. Your insurer may ask for it after a fire or a claim.
- Never back-feed the grid. Plugging a generator or inverter into a wall socket to power the building can kill the people repairing the power lines. A proper changeover switch prevents it.
- Give batteries space and ventilation. Lead-acid batteries can give off gases when charging, and any large battery is a fire risk in a cramped, hot or cluttered cupboard. Keep them away from flammable material.
- Check what your grid-connected system needs. If a system can feed power back into the municipal network, your municipality may need to approve it.
- Do not overload sockets or daisy-chain extension leads. They are one of the most common causes of electrical fires.
Test It, Then Maintain It
A backup system you have never tested is a hope, not a plan.
- Once a month, pull the plug on purpose and check that everything stays up for the expected time. Note the runtime, and watch it drop as batteries age.
- Expect to replace standard UPS batteries every few years. They fade quietly, and the first time you find out is often the first time you need them.
- Read the alarms. A UPS that beeps is telling you something.
- Keep the shutdown software and firmware up to date.
- Label circuits and sockets so staff know what is on backup and what is not.
A Business Continuity Checklist
- Every device that needs power listed, with an honest wattage
- Connectivity — ONT, router, firewall, switch, access point — on its own backup
- A cellular failover for when fibre goes down
- Servers and NAS on a UPS with tested automatic shutdown
- Tills and payment equipment on backup with their network gear
- Laser printers kept off UPS battery outlets
- Surge protection on power and network cables, replaced every few years
- Fixed installations done by a registered electrician, with a Certificate of Compliance
- A monthly pull-the-plug test with the runtime recorded
- A tested backup and a cloud copy of everything important
- Staff who know what to do when the lights go out
Mistakes That Leave You Offline
- Sizing for the whole office. It produces a system nobody can afford. Start with connectivity and work up.
- Buying a UPS by VA alone. The rating says how much it can supply, not how long. Runtime depends on the battery.
- Forgetting the switch or access point. A backed-up router feeding an unpowered switch gets you nowhere.
- Cheap modified sine wave inverters. They save money on the shelf and cost it back in dead power supplies.
- No shutdown software. A UPS that only beeps until the battery dies gives you a hard shutdown anyway.
- Never testing. Batteries fail quietly.
- Unregistered installation. It can void your insurance at exactly the wrong moment.
How IT-Support-SA Can Help
We handle the IT side of power protection for South African businesses: auditing what needs protecting and what it really draws, specifying the right UPS or backup for each part of your setup, configuring automatic shutdown for servers and storage, checking that your network stays up on backup power, adding cellular failover, and testing the whole arrangement properly. Wiring and inverter installations should be done by a registered electrician, and we work alongside yours. For a business we already look after, this is usually folded into planned work; see our IT support cost guide for how managed support is typically priced, or our guide to choosing an IT company in KwaZulu-Natal if you are still comparing.
Conclusion
You cannot control when the power goes off, but you can decide what happens when it does. Keep your connection alive first, because it is small, cheap and valuable. Give servers time to shut down properly. Protect tills and cameras, keep desktops off the backup unless you truly need them, move what you can to the cloud, use the right kind of backup for each job, and have anything fixed installed by a registered electrician. Then pull the plug on purpose, once a month, before the grid does it for you.
Contact IT-Support-SA for a power-protection check — we will map what you rely on, tell you plainly what needs backup and what does not, and quote the simplest setup that keeps you trading. We support businesses across Pietermaritzburg, Durban, Ladysmith, Johannesburg, Cape Town and all 9 provinces of South Africa.