Short answer: Four things decide whether a home internet connection survives an outage: the box that receives your provider's signal (a cable or DSL modem, or a fiber optical network terminal, called an ONT), the router that creates your Wi-Fi, any separate unit your provider installed, and the charger that keeps your phone alive. Many homes have only two or three of these boxes, because some providers supply one combined unit. This checklist helps you find which ones you own, label them, and test them before the power goes out.
This article expands our planning guide, Home Wi-Fi During an Outage: Router, Modem, and Backup-Power Planning. That guide explains the terms. This one helps you identify and test your own equipment. Last reviewed September 30, 2026.
Why Powering Only the Router Often Fails
Your router and your modem or ONT work as a chain. If the box that connects to your provider has no power, a powered router can still make a local Wi-Fi network, but nothing behind it reaches the internet. The FCC and FEMA also warn that broadband-enabled telephone service will not work during an electric outage without a battery or other backup power source (FCC/FEMA Emergency Communications Tips).
Step 1: Identify the Four Dependencies
Walk to the spot where your internet enters the home and look at what is plugged in. Then answer these four questions.
- Modem or ONT (the provider-facing box). Look at the cable entering it. A round coaxial cable usually means a cable modem. A phone-style line usually means DSL. A thin fiber cable means an ONT. The ONT may not sit next to your router, so check your provider's setup documents if you can't find it.
- Router. This is the box that creates your Wi-Fi. If your provider gave you a single unit that does both jobs, you have a combined gateway, and that one unit covers items 1 and 2.
- Anything else in the chain. Note extra Wi-Fi nodes, network switches, or a provider-installed battery. If you have a battery, the FCC advises testing it periodically, learning how long it should last, and knowing how to replace it (FCC/FEMA Emergency Communications Tips).
- Phone charging. Ready.gov advises planning batteries and other alternative power for the things you rely on, such as a portable charger or power bank (Ready.gov, Power Outages). Count the charger, cable, and any power bank your household would use.
Step 2: Fill In Your Device Sheet
Copy this into a notebook. Write one line per item.
- Modem, ONT, or combined gateway: model ______ | where it sits ______ | power adapter label reads ______ | on backup power? yes / no
- Router (if separate): model ______ | where it sits ______ | power adapter label reads ______ | on backup power? yes / no
- Extra nodes or switches: ______ | ______ | ______ | yes / no
- Phone charging: charger and cable ______ | power bank ______ | charged? yes / no
- Home phone: corded / cordless / internet-based / not sure ______
The power adapter label shows a rating, which is a ceiling and not what the device actually draws. To size a backup unit, measure real use with a plug-in meter and follow the steps in our room-by-room runtime worksheet. If the numbers on a backup unit's label are unfamiliar, read Power Station Labels: Watt-Hours, Watts, and Runtime Estimates Explained.
Step 3: Run the Test
Do this while power is on, at a time when a short internet interruption is fine.
- Plug every item you marked “yes” into your chosen backup source.
- Unplug the backup source from the wall, or switch off the outlet, so the equipment is running only on backup.
- Wait a few minutes. Confirm the lights on the modem or ONT and the router come back to their normal state.
- On a phone, check that a web page loads over Wi-Fi.
- Note the time and check again after 30 minutes. Write down what still works.
- If the router shows Wi-Fi but pages will not load, check the modem or ONT. It is the most common miss in this chain.
- Restore wall power, and record any device that needed a manual restart.
A home test cannot show what happens on your provider's side. Your connection can stay down if equipment on your street or at your provider's facility loses power, so ask your provider what backup exists on its end.
Step 4: Test Phone Charging
- Fully charge your power bank now, and check that its cable fits your phone.
- Charge a phone from it once and note how much of the phone's battery it restored. That is your real figure.
- Ready.gov advises keeping phones charged and having alternative charging methods ready (Ready.gov, Power Outages). The FCC and FEMA note that a charged laptop or tablet can recharge a phone over USB, but doing so may drain the laptop or tablet (FCC/FEMA Tips for Communicating During an Emergency).
- If you charge a phone from a car, the Department of Energy says to keep the car in a well-ventilated place (Department of Energy, Keeping Mobile Devices Charged).
- If you plan to use your phone as a hotspot, test that too, because it may drain the battery faster than ordinary use. That expectation is an assumption to check, not a figure I have a source for.
Check Your Home Phone
The FCC and FEMA say traditional telephone service may work during electric outages, though you may need a corded phone, because many cordless home phones rely on electric power. They also say broadband-enabled phone service will not work without a battery or other backup (FCC/FEMA Emergency Communications Tips). Ready.gov advises determining whether your home phone will work in an outage and how long battery backup will last (Ready.gov, Power Outages). If you are unsure which type you have, ask your provider.
In 2015 the FCC adopted rules requiring providers of certain fixed residential voice services that are not line-powered to offer an option to buy backup power, and to give subscribers information about its limits and duration (Federal Register, Ensuring Continuity of 911 Communications). Ask your provider what applies to your service today.
Limits and When to Get Professional Help
- Medical devices. If anyone in your home depends on an electrically powered medical device or refrigerated medicine, do not treat this checklist as your plan. Ready.gov advises talking to your medical provider about an outage plan for both (Ready.gov, Power Outages).
- Emergency calls. Do not assume an internet-based phone line will work. Confirm with your provider and keep a charged mobile phone available.
- Generators. Ready.gov says generators, camp stoves, and charcoal grills belong outdoors and at least 20 feet from windows (Ready.gov, Power Outages).
- Home wiring. Do not connect a power source to your home's wiring or panel yourself. Ask a licensed electrician.
- Provider equipment. Do not open or modify your ONT or modem. Ask your provider about battery options and replacement.
What to Do Next
- Fill in the device sheet this week.
- Run the wall-unplug test and the phone-charging test, and note the results.
- Call your provider with three questions: does my ONT or modem have a battery option, will my home phone work in an outage, and what backup power exists on your network?
- Only after that, decide whether you need extra equipment. You may find that a charged power bank and a written plan cover most of what you need. For food-safety and appliance planning, see Can a Portable Power Station Run a Refrigerator?
Sources
- Ready.gov, Power Outages
- Federal Communications Commission, FCC/FEMA Emergency Communications Tips
- FCC/FEMA Tips for Communicating During an Emergency (PDF)
- U.S. Department of Energy, Keeping Mobile Devices Charged
- Federal Register, Ensuring Continuity of 911 Communications
By InfinitePowerSolutions.com Technology Desk. This article is general educational information, not electrical, medical, or telecommunications advice, and it does not recommend any product. It reflects no hands-on testing by our staff. See our Editorial Standards for how we research articles.
