Category: Technologies · Last updated 28 Sept 2026
What is the nbn battery backup and do I need one?
Why nbn connections stop during a blackout, and how backup power works.
Unlike the old copper phone network, which was powered from the telephone exchange, nbn equipment relies on power at your home. That means your nbn connection - and any home phone running over it - stops working during a power outage unless you have backup power.
Who this affects
Every nbn technology type. On FTTP, HFC, FTTC, Fixed Wireless and Satellite, the nbn Connection Box and your modem both need power. On FTTN and FTTB, your modem needs power.
Backup power options
- A UPS (uninterruptible power supply) - a battery unit your modem and nbn equipment plug into, which keeps them running for a period during a blackout. How long depends on the battery size.
- Battery backup for FTTP - some older FTTP installations have an nbn battery backup unit. These are no longer supplied as standard.
- A mobile phone - the simplest backup for calls, as long as the mobile network in your area has power.
If anyone in your household relies on a home phone or medical alarm for health or safety reasons, talk to us before you connect. We can help you plan backup power or a mobile-based alternative, and you should also register your medical alarm with nbn Co.
Related Articles
- TechnologiesWhat is nbn and how does it work?A plain-English explanation of Australia's national broadband network, how it reaches your home, and why your choice of provider still matters.
- TechnologiesFibre to the Premises (FTTP): what it is and what to expectHow FTTP works and why it's the fastest nbn technology type available.
- TechnologiesFibre to the Node (FTTN): what it is and what to expectHow FTTN works, why your copper line and in-home wiring matter, and how to choose a speed tier.
- TechnologiesFibre to the Curb (FTTC): what it is and what to expectHow FTTC differs from FTTN and what the small device outside your home does.
Was this article helpful?
Your feedback helps us improve our support content.