Keeping Your Internet On Through Load-Shedding

Why your fibre dies the moment the lights go off

Fibre carries light, not electricity, so the cable into your home is unaffected by load-shedding. The problem is everything that converts and broadcasts that signal. Two devices in your home need mains power: the ONT (the small white box where the fibre plugs in, sometimes called the fibre modem) and your Wi-Fi router. Cut power to either and your connection drops instantly, even though the line outside is perfectly healthy.

There is a second, less obvious problem further up the chain. Open-access networks like Openserve, Vumatel, Frogfoot and MetroFibre run street-side cabinets and aggregation points that also need power. Many of these have their own batteries or generators, but battery life varies, and longer or back-to-back slots can drain them. So even with your home gear on battery, you may occasionally find the wider network has gone dark — though in well-maintained suburbs that is the exception, not the rule.

• +ONT (fibre box): needs power — usually low-voltage DC, low draw
• +Wi-Fi router: needs power — typically the bigger consumer of the two
• +Street cabinet / aggregation: the network's responsibility, usually battery-backed
• +The fibre cable itself: needs no power at all

Why mobile data is your most resilient backup

LTE and 5G can keep working through load-shedding because the mobile networks have spent heavily on tower backup — batteries, and generators at key sites. In practice, when your fibre and home Wi-Fi go down, a phone or LTE router on a mobile network is often still online. That makes mobile data the natural failover for South African households.

Coverage and tower backup are not equal across networks or areas. As a rough guide, the larger mobile operators have invested the most in keeping towers up during extended outages, while battery life can be patchier on smaller or rural sites regardless of provider. The honest answer is that it depends on your location — the tower you connect to matters more than the brand on the box. Before committing, test a prepaid SIM from one or two networks at your home during an actual load-shedding slot and see which stays up.

• +Tethering from your phone: quickest, zero extra hardware, fine for a laptop or two
• +A dedicated LTE/5G router with its own SIM: better for the whole household
• +5G where available: fast enough to genuinely replace fibre for streaming and calls
• +Always test locally — the tower nearest you decides how well this works

Option 1: A mini-UPS for your router and ONT (the smart-money pick)

For most homes, the best-value fix is a small dedicated battery — often sold as a 'mini-UPS' or 'router UPS'. These are compact lithium units, roughly the size of a paperback, that sit between the wall and your ONT and router. They output the low DC voltages networking gear needs (commonly 9V and 12V) and switch over instantly when the power drops, so your connection never even flickers.

Because routers and ONTs draw very little power, a decent mini-UPS can keep them running for several hours on a single charge — comfortably through a standard two-to-four-hour slot, and sometimes through two. The catch is that it powers nothing else: your laptop, phone and TV run off their own batteries. For laptop-and-phone households, that is usually all you need.

• +Powers: ONT + router only (and maybe a small switch)
• +Runtime: typically several hours, depending on capacity
• +Cost tier: budget — the cheapest way to keep Wi-Fi alive
• +Best for: anyone who just wants the connection to survive the slot

Option 2: An inverter or portable power station (whole-desk backup)

If you want to power more than the network gear — a laptop charger, a monitor, a desk lamp, maybe a TV box — step up to a portable power station or a small inverter-and-battery setup. These give you standard wall sockets, so you plug in whatever you like rather than being limited to DC outputs. A mid-sized unit will run a home-office desk plus your router for the length of a typical slot.

This is the middle tier: more flexible and more powerful than a mini-UPS, but heavier, pricier, and something you have to keep charged. A full home solution — an inverter wired into your distribution board, or solar with a large battery — sits above this and keeps lights, fridge and internet on through almost anything, but that is a significant installation and expense. For staying online specifically, you rarely need to go that far.

• +Powers: router/ONT plus laptops, monitors, small appliances
• +Cost tier: mid — more than a mini-UPS, less than a fixed install
• +Whole-home inverter/solar: premium — a wired-in installation
• +Best for: people who work from home and need a working desk, not just Wi-Fi

A practical setup that just works

You do not need to over-engineer this. For most South African homes, a mini-UPS on the ONT and router handles short-to-medium slots, with mobile data ready as failover for the rare times the wider network goes down or a slot runs long.

Set it up once and forget it. Keep the mini-UPS permanently plugged in and charged so it is always ready; keep a backup SIM topped up or on a small monthly bundle; and if your main router supports a USB modem or has a failover mode, configure it so the household rolls onto mobile data automatically when fibre drops. Match the battery to your slot length — if you regularly get four-hour stages, size up the capacity so you are not left dark halfway through.

• +Plug the mini-UPS into ONT and router, leave it on charge permanently
• +Keep a tested backup SIM (or LTE/5G router) topped up for failover
• +Enable automatic failover on your router if it supports it
• +Size your battery to your worst regular load-shedding stage, not the best case

Frequently asked questions

Will my fibre work during load-shedding if I keep my router on?

Usually yes. Keep your ONT and router powered with a battery or mini-UPS and your connection should stay up, because the fibre line itself needs no power. The exception is when the street cabinet or your network's local equipment runs out of battery — less common, but it does happen on long or back-to-back slots.

Do I need to power both the ONT and the router, or just one?

Both. The ONT brings the signal in from the fibre and the router shares it over Wi-Fi, so if either loses power you go offline. Any battery solution must feed both. The good news is they draw very little, so this is cheap to do — a small mini-UPS handles both for hours.

Is a mini-UPS enough, or should I buy a full inverter?

For keeping just your internet alive, a mini-UPS is almost always enough and far cheaper. Step up to a portable power station or inverter only if you also want to run laptops, monitors or other appliances off the same backup, or if you want to keep the whole house going through every stage.

Which network keeps its towers up longest during outages?

It depends on your location, because the specific tower you connect to matters more than the brand. The larger mobile operators have invested most in tower batteries and generators, but coverage varies suburb to suburb. The reliable way to choose is to test a prepaid SIM from one or two networks at your home during an actual load-shedding slot.

Can I just use my phone's hotspot instead of buying anything?

For light use, yes — tethering a laptop to your phone is a perfectly good free backup if your network's towers stay up in your area. The limits are battery drain on your phone, data costs, and that it won't comfortably serve a whole household of devices. For more than a person or two, a dedicated LTE or 5G router is worth it.