Quick answer: The fibre network itself usually keeps working in a power cut, but your connection at home goes down because your ONT (the fibre box on the wall) and your router need electricity. To stay online, plug both into a UPS, inverter or backup battery. How long you stay connected depends on the battery’s capacity and how much power the two devices draw.
Power cuts still happen, from planned maintenance to storms and local faults, and they can bring chaos to our daily lives. Whether you’re working from home, streaming your favourite shows or gaming online, a power cut can throw everything into disarray – especially if your internet goes down.
But does fibre internet actually stop working during a power cut? The answer isn’t a simple yes or no. Fibre networks are operational during power cuts but your connection at home depends on whether your router and ONT (Optical Network Terminal) have power. In this article we’ll look at how different types of internet react to power outages, why mobile networks struggle and how you can keep your fibre internet running even when the lights go out.How Power Outages Affect Internet Connectivity
When the power goes off so does most of South Africa’s internet infrastructure. However, different types of internet react in different ways:- Fibre Internet: Fibre cables don’t need electricity to transmit data. However, your home’s ONT and router require power so without a backup solution your internet will go down.
- LTE & 5G Mobile Networks: Mobile towers have backup batteries but during prolonged power outages these batteries run out and you get weak or no signal.
- ADSL: ADSL runs through copper telephone lines and relies on powered exchanges to function. Most ADSL connections fail during power outages.
- Satellite Internet: The satellites themselves are not affected by power cuts. However, they require a satellite modem and dish both of which need electricity.
Does Fibre Internet Work Without Electricity?
The good news is that fibre internet itself doesn’t need electricity to work. Fibre-optic cables use light to transmit data so as long as your Fibre Network Operator (FNO) and Internet Service Provider (ISP) have power the network itself is live.Why Does Fibre Go Down During a Power Cut?
- Your Router & ONT Lose Power: Even though the fibre network is operational your home devices need electricity to receive and transmit data.
- Your ISP’s Network Can Be Affected: While most ISPs have backup power for their infrastructure some may be affected during prolonged outages.
- Power Surges & Damage: Sudden outages and returns of electricity can sometimes damage network equipment and cause temporary downtime.
How to Keep Your Fibre Internet Running During Power Cuts
If you want uninterrupted connectivity during power cuts there are a few simple backup power solutions to consider:1. Using a UPS (Uninterruptible Power Supply)
A UPS is one of the easiest and most cost-effective solutions to keep your fibre internet running during power cuts. ✅ How it helps: A UPS supplies backup power to your ONT and router, keeps them running for a limited time. How long does a UPS last? It depends on the UPS battery and the power draw of your ONT and router; check the manufacturer’s runtime figures. Recommended UPS models for home fibre:- Mecer 2000VA Line Interactive UPS (for longer uptime)
- Ellies 1200VA UPS (budget-friendly option)
- EcoFlow Delta Mini (a portable power station rather than a UPS, for high-power needs)
2. Using an Inverter or Generator
For longer outages, a power inverter or generator can keep your entire home network running. ✅ How it helps: Inverters connect to your home’s electrical system, ensuring multiple devices stay powered. Generators provide backup electricity but are noisier and require fuel. Best for: Households that experience long power outages (4+ hours).3. Power-Cut-Friendly Internet Plans
Some ISPs offer backup-ready fibre solutions, which include:- Battery-powered routers that work without mains electricity.
- Hybrid fibre & LTE packages that switch to mobile data when fibre goes offline.
- Cloud-based failover systems that reroute traffic to secondary connections.
Alternative Internet Solutions When Fibre is Down
Even with backup power, it’s good to have a secondary internet option in case of network disruptions. Here’s how alternative internet types compare:1. LTE & 5G: Do They Work During Power Cuts?
✅ Short power cuts: Mobile networks stay online for a while since cell towers have backup batteries. ❌ Long outages: Once batteries drain, signal drops or disappears entirely, making LTE unreliable during extended power outages.2. Satellite Internet: A Backup Solution?
✅ Satellites unaffected: Satellites aren’t affected by power outages on the ground, but your dish and router still need backup power. ❌ High costs & latency: Satellite internet is expensive and slower than fibre.3. Public Wi-Fi & Co-Working Spaces
If your home internet is completely down, consider:- Local coffee shops with generators.
- Co-working spaces offering uninterrupted fibre connectivity.
- Friends or family with better backup setups.
