How to Prepare for a Power Grid Failure or EMP Event

A power grid failure or EMP event can cut off electricity, communication, and refrigeration with no warning, and utility crews may need days or longer to restore service after a widespread outage. The standard response is the same one behind all grid-down preparedness: shield your electronics from electromagnetic damage, secure a backup power source, and keep enough food, water, and supplies on hand to sustain your household for at least 72 hours.

What Causes a Power Grid Failure or EMP Event

Power grids can go down for a range of reasons: severe weather, equipment failure, cyberattacks on utility infrastructure, or a natural or man-made electromagnetic pulse (EMP). An EMP is a burst of electromagnetic energy that can damage or disable unprotected electronics, including phones, radios, and vehicle electronics. Whatever the cause, the practical result is the same: no lights, no refrigeration, spotty or nonexistent communication, and a household that has to rely on what it already has on hand.

How to Protect Electronics From an EMP: Faraday Bags

A Faraday bag (or Faraday cage) is a shielded enclosure that blocks electromagnetic signals from reaching whatever is stored inside it. Keeping a backup phone, a hand-crank or battery radio, and spare batteries inside a Faraday bag is a common, low-cost way to keep at least one line of communication and information intact if an EMP event damages unprotected devices.

A few practical notes on using Faraday protection:

• Store a spare, not just your primary device. If your daily-use phone stays in your pocket, it will not be shielded when it matters. Keep a backup device sealed and ready.
• Prioritize communication and information tools. A battery or hand-crank emergency radio is worth shielding even if you do not shield everything else.
• Check the seal. A Faraday bag only works if it is fully closed. A partially sealed bag offers little to no protection.

Backup Power Options When the Grid Goes Down

Once the grid is down, the next problem is keeping essential devices charged and, if needed, running small appliances or medical equipment. Portable solar power stations and battery power banks let a household generate or store electricity independent of the grid, which matters most for medical devices, communication gear, and basic lighting. Match your backup power capacity to what you actually need to run, rather than assuming a small power bank will cover a full household through an extended outage.

Building a Grid-Down Preparedness Plan

Protecting electronics and securing backup power only solve part of the problem. A full grid-down plan should also account for water, food, first aid, and a way to leave home quickly if conditions require it. Ready.gov recommends every household be able to sustain itself for at least 72 hours without outside help, with roughly one gallon of water per person, per day, as a baseline. Our Complete 72 Hour Fully Loaded Bug Out Bag is built around that same 72-hour standard, and our Bug Out Gear collection covers the broader category if you are building a kit piece by piece.

If you are starting from scratch, our guide on what a 72-hour kit is and why it matters is a good next step.

Check and rotate your supplies periodically. Twice a year is a common rule of thumb, so batteries, water, and food stay usable when you actually need them.

Frequently Asked Questions

What is an EMP and how does it damage electronics?

An EMP (electromagnetic pulse) is a burst of electromagnetic energy that can damage or disable unprotected electronic devices. Shielding electronics inside a Faraday bag or Faraday cage is a common way to protect them from this kind of damage.

How long should my household be prepared to go without power?

Ready.gov guidance recommends households be prepared to sustain themselves for at least 72 hours without outside help. That standard applies to grid-down events as well as most other emergencies.

Do I need a Faraday bag if I already have a backup generator or solar power station?

Yes, they solve different problems. A backup power source keeps devices charged, but it will not protect electronics from EMP damage. A Faraday bag is what shields sensitive electronics like radios and spare phones from an electromagnetic pulse.

How much water should I store for a grid-down emergency?

A commonly cited guideline is about one gallon of water per person, per day, which covers both drinking and basic sanitation needs.