72 hours.
A workable household plan.

Start with three days, then adapt to local risks and official guidance. Plan for the people, access needs and pets in your home.

Supplies you can reach in the dark

• Drinking water and ready-to-eat food; a manual can opener and suitable pet supplies. Follow local official quantities.
• Medication, first-aid supplies, prescription details, hygiene items and accessibility equipment. Plan medication storage with your pharmacist.
• Battery lights, spare batteries, a charged phone power bank and the correct cables. Prefer torches to candles.
• Battery or wind-up radio, warm layers, essential documents and a paper household contact sheet.
• An affordable reserve of mixed small notes and coins, plus a physical payment card from a separate banking group.
• Offline maps, contact numbers, printed account backup codes stored securely and a separately reachable recovery method.

Before an outage

• Charge batteries; test the torch and each backup device. Agree where everyone will meet.
• Read both ONT and router power-adapter labels. Complete the compatibility checks on page 3.
• Print the wallet contacts. Rehearse account recovery without your everyday phone.

Official supply guidance: FEMA emergency supply checklist. Outside the US or UK, use your local emergency authority’s advice.

Keep another way to pay.

Cash and separate payment routes can help when a card terminal, app or network fails. They do not guarantee a shop can trade.

Small-note cash worksheet

Outage & Prep starting example: $200 for two people over three days, plus $40 per additional person, scaled by days. This is a channel planning example, not an official minimum. Use your actual essential spending and keep only what you can afford and store securely.

Carry a physical Chip & PIN card and use it periodically. Offline acceptance varies by terminal and payment method. Pay-at-pump can place a temporary hold; amounts vary.

Check both boxes.
Then check the load.

The fibre ONT and router both need power. So may a separate telephone adapter. A battery powers the home equipment; it cannot guarantee the outside network remains available.

Compatibility record

Examples such as 12V DC, centre-positive, 1.5A–3A and 5.5 × 2.1mm / 2.5mm are not universal. Match exact voltage, polarity, connector and required per-port / total current before connecting anything.

Capacity ÷ demand

Estimated runtime (hours) = capacity (Wh) × 0.85 ÷ average load (W). At 18W, an 88Wh DC UPS gives an estimated 4.2 hours. A 512Wh AC station at a 60W average gives about 7.3 hours. The 85% factor is a planning assumption, not a measured product specification.

Fridges cycle; starting surge is different from average running demand. Check the inverter’s continuous and surge output. Keep fridge and freezer doors closed during a cut; follow local food-safety advice. Agree medical equipment backup with your care team and manufacturer.

US: ask your provider how its voice service and battery options work during an outage. Other countries: confirm your local provider’s arrangements.

Mains equipment: 120V / US NEMA 5-15. Other countries: match local standards. Never back-feed home wiring.

Different brands?
Check the group.

Use this map to identify group membership. It does not establish a shared IT engine or simultaneous failure. Verify the legal institution before opening an account.

FDIC insurance does not keep card networks, ATMs or ACH online. Credit unions may use NCUA insurance; Fidelity cash management can involve underlying sweep banks. Check the legal entity and terms.

Make the second route usable

• Choose a separate institution / group and check the scheme printed on each card.
• Carry a usable physical card and know the PIN. Keep recovery independent of your phone.
• Confirm access to a backup balance before relying on it. Rehearse a small payment.

A second mobile network

US host-network candidates include Verizon, AT&T and T-Mobile; verify local coverage and device support. A second reseller brand may use the same network. Different networks can still share infrastructure.

Lose the phone.
Keep the way back in.

Tonight’s three steps

• Hide SMS and notification previews on the lock screen.
• Enable the SIM PIN using your carrier’s instructions. Store the PUK safely. Never guess the PIN or PUK; wrong attempts can permanently lock the SIM.
• Print backup codes for key accounts and register a separate home device or hardware key. Test it without the everyday phone.

A SIM PIN locks the SIM / eSIM after a restart or removal; it does not prevent carrier-account takeover. A security key works only with supported, registered accounts; it does not recover a SIM. Carrier replacement eSIM delivery varies. Vodafone and Three, for example, email replacement eSIM codes.

Break the circular dependency

Family callback plan

• Agree a private family verification phrase and a separately known callback number.
• When someone asks urgently for money, stop and call them on that known number.
• Keep the phrase private; a familiar voice alone is not identity verification.

Sources for your edition

Ready.gov: emergency supply kit · FCC: emergency communications · FDIC: disaster preparation · Apple: SIM PIN and PUK · Google · Backup codes