Internet Outages During Power Cuts: Staying Connected When the Lights Go Out

In modern Greek households, the loss of internet connectivity during a power outage is often more immediately disruptive than the darkness. Remote workers lose their connection to employer systems. Students cannot access online resources. Families are cut off from news and communication. Even the process of reporting an outage on Outage.gr or calling DEDDIE becomes harder without reliable connectivity.

Understanding why internet fails during power outages, how long different types of connections last, and what you can do to maintain connectivity is increasingly important practical knowledge for Greek residents.

Why Internet Fails During Power Outages

The short answer: because your router and modem need electricity. When your home's power goes out, unless you have backup power for your networking equipment, your internet connection fails along with the lights — even if your ISP's own infrastructure is still running.

But there is a second layer to the problem. Your ISP's local network equipment — the street cabinet, the DSL access multiplexer, the fiber optical network terminal (ONT) in the building, or the cable node serving your area — also needs power. ISPs maintain battery backup at many of these locations, but the duration varies.

DSL (ADSL/VDSL) connections: The telephone exchange serving your line maintains UPS battery backup at the exchange, typically providing 4–8 hours of backup power. During this window, your DSL service could remain available if you have backup power for your router. After the battery depletes, the exchange also loses power and the service fails at the network level.

Fiber (FTTH/FTTB) connections: Most fiber connections use an ONT device at or near your premises that requires a power supply. When mains power fails, the ONT fails unless it has its own UPS. ISPs vary in whether they provide ONTs with battery backup.

Cable (HFC) connections: Cable head-ends and nodes maintain backup power with varying durations. In Greece, cable infrastructure is primarily operated by Nova (formerly HOL) in certain urban areas.

4G/5G mobile data: Mobile network base stations typically have 4–8 hours of battery backup, sometimes extending to 24 hours at major sites. During power outages, 4G and 5G connectivity often remains available significantly longer than fixed-line internet — making mobile data a critical backup.

How Long Your Equipment Runs Without Power

Understanding your equipment's power dependency helps you plan:

Your router (without UPS): Fails immediately when mains power fails.

Your ONT/modem (without UPS): Fails immediately when mains power fails.

Your router + modem on a UPS: A standard home UPS (600 VA, €60–80) can power a router and modem (typically 10–15W combined) for 4–8 hours, depending on UPS battery capacity.

A mobile hotspot or smartphone in hotspot mode: Can provide 4G connectivity for 4–8 hours on its own battery, depending on usage and battery condition.

Practical Strategies for Staying Connected

Strategy 1: UPS for your router and modem The most complete fixed-line backup solution. A UPS with a capacity of 600–1000 VA (available from electronics retailers for €60–120) will power most home networking equipment for several hours. Connect your router and modem (or ONT) to the UPS, but not large appliances — the goal is to extend networking device runtime, not power everything.

Strategy 2: Mobile data backup A prepaid SIM with a data allowance is the most reliable backup. When your fixed-line internet fails during a power outage, switching to mobile data keeps you connected as long as the mobile network has power (usually 4–8 hours of battery backup at each base station).

Many modern routers support a USB port for a 4G dongle or can use a connected phone's mobile hotspot. Some ISPs offer routers with built-in 4G failover — when fixed-line service drops, the router automatically switches to 4G.

Strategy 3: Mobile hotspot Simply enabling the mobile hotspot feature on your smartphone allows other devices to use your mobile data connection when the router is down. This drains phone battery faster than normal use, so keep your phone on a power bank when using it as a hotspot during an outage.

Strategy 4: Public Wi-Fi fallback Many shopping centres, cafés, and public spaces maintain generator backup during extended outages. In an extended residential outage, a coffee shop or shopping centre can provide both power for charging and internet access.

Special Considerations for Remote Workers

For those working from home, internet connectivity during power outages is a professional necessity, not just a convenience. Recommended baseline setup:

• UPS for router, modem/ONT, and work computer
• Mobile data backup plan (a secondary SIM or a prepaid data plan)
• Cloud backup of work in progress (so that if the UPS runs out mid-session, work is not lost)
• Communication plan with employer (agree in advance that you will switch to mobile data during outages and notify them via mobile if unable to connect via primary connection)

Reporting Internet Outages

When your internet fails, check Outage.gr — community reports from neighbours with mobile data can confirm whether the outage is widespread. If it is, report it yourself (using mobile data) to help others in your area know the problem is not isolated.

Reporting an internet outage with your ISP name selected helps build the provider accountability data that Outage.gr publishes, contributing to a public picture of ISP reliability across Greece that benefits all consumers.