Electromagnetic Pulse: What’s the Risk?

An electromagnetic pulse (EMP) is a burst of energy that is radiated or conducted by a source such as the sun or some form of explosive device. Whenever electrical current flows through a wire it produces an electrical and a magnetic field that radiate out perpendicular to the current flow. The size of these fields is proportional to the current flowing—more current, larger fields. As you’ll learn shortly, the length of the wire directly influences the strength of the current induced by an electromagnetic pulse.

For reference, this is the simplest and not-so-dangerous form of EMP in the home.

Flicking on a light switch to allow current to flow and energize a lamp produces a short burst of electrical and magnetic energy. The burst is so small it’s barely noticed. The switching actions in electrical circuitry, motors, and gas engine ignition systems produce small EMP pulse trains that can cause static on a nearby radio or television, so filters are used to absorb the effects of these small bursts of energy and remove the interference.

A higher energy pulse can occur when a charge of electricity is quickly discharged. This electrostatic discharge (ESD) can shock a person or cause a spark—dangerous around fuel vapors. As kids we would rub our feet on a carpet, and then touch a friend creating an ESD discharge. Then we’d all laugh and try to shock someone else. ESD is a form of EMP.

As the energy pulse gets stronger it can damage buildings and people. Lightning is a high energy form of EMP. The electrostatic discharge from a lightning bolt can be dangerous and actually start fires. Fortunately most lightning is shorted into the earth where the electrical charge is absorbed. The lightning rod invented by Benjamin Franklin saved many homes and barns from EMP damage by shorting lightning strikes around buildings to ground.

Power line surges occur when electrical appliances are energized. This surge is a form of EMP and washers, dryers, and vacuum cleaners are designed to handle this. Electronics can be damaged by electrical surges if protection is not designed into the equipment. Surge protectors can help but it’s best to unplug electrical and electronic equipment during a power outage to remove surge damage risks when power is restored. Then selectively re-energize everything.

Events such as nuclear explosions, high altitude non-nuclear detonations, or solar storms can produce high energy EMP that can be damaging to electrical and electronic equipment located far from the source of the event. These are the types of events that threaten our electrical power grid and the functioning of most electric and electronic things in our lives.

According to a report I read recently, high energy EMP can slam our electrical systems with a magnetic field as high as 4000 A/m (amps per meter) and an electric field stronger than 10 ⁵ V/m. These fields cause current to flow in wiring—the longer the wire, the more current flow. This current can be so strong it breaks down components in the path heating (frying) circuitry and preventing proper operation of equipment. Long lines of wire such as power and telephone lines can experience huge currents that can damage electrical substations and telephone relays. The current can overload transformers causing them to fail—some wiring can actually melt. It could take months to replace large transformers and repair damage done by a catastrophic EMP event.

A high energy EMP can disable or “fry” the electronics in your vehicle. Vehicles built without electronic ignitions (1980 or older) should still operate after a catastrophic EMP strike. So find and hold on to transportation that doesn’t use electronic ignition “just in case.” An old 1966 Ford Mustang is ideal for a post-EMP world. A bicycle or skate board could be all the transportation you may have available. Regardless, life will be different.

In your preparation be aware that all of the electrical and electronic devices in your home and garage are at risk for EMP damage. These could include:

• computers
• displays
• printers
• routers
• control systems
• transformers
• generators
• power supplies
• landline phones
• electronic circuits
• televisions
• radios (AM/FM, CB, shortwave, etc.)
• DVD players
• game devices
• entertainment centers
• video games
• amplifiers
• communication systems (transmitters, receivers, PA, intercomm)
• cables (data, telephone, coax, USB, etc.)
• wire (especially long lengths)
• antennas (external and internal)
• electric power cords
• ignition systems (auto and aircraft)
• furnace circuitry
• air conditioning appliances
• batteries (all types)
• flashlights
• relays
• alarm systems
• alternators
• charge controllers
• inverters
• meters
• calculators
• power tools
• test equipment
• spare parts
• chargers
• monitoring devices (CO2, smoke detectors, etc.)
• home medical electronics
• pacemakers
• life support systems
• hearing aids
• medical monitoring devices

According to my research, small systems are not likely to be affected by EMP if they are isolated from the power grid. Therefore, if you have advance warning of a coming EMP, disconnect everything plugged into the electrical sockets in your home and garage to isolate appliances and devices from those long, current-carrying wires (circuits) connected through the walls to the power distribution panel on the outside of your home.  Don’t forget to unplug your furnace blower motor and thermostat circuitry. Disconnect your solar panels and your home from the power grid—open the isolation switches between your solar panels and the inverter, and between the inverter and the power distribution panel. Also open the switches between the power distribution panel and the house circuits and between the power distribution panel and the local electrical grid. Isolate to preserve.

It takes just over eight minutes for a solar flare eruption on the surface of the sun to blast out and send an EMP to earth, so keeping informed is important. If you don’t get (or receive) advance warning, then all bets are off. And this is likely if a high altitude bomb is exploded above the center of the country. In this case you’ll know it happened when power goes out and vehicles stop running and roll to a stop. In this case, the EMP protections you have in place and the strength of the EMP pulse will determine what power and capabilities you’ll have from that moment on. Prior planning and proper protection can be critical. So select those devices and equipment that are especially sensitive or critical to have after an EMP, and protect these from damage by storing them in special containers.

Want to know more? Check out these related articles:

Electromagnetic Pulse: Protecting Your Components

EMP Effects On People | Electromagnetic Pulse

EMP Incoming! | What to Expect from an EMP