Rotating outages or rolling blackouts are sometimes called "load shedding", and they are intentionally engineered power outages. These rolling blackouts are used as a last resort by utility companies in order to prevent the whole power system from shutting down. Rotating outages usually happen in response to situations where the supply of power is exceeded by demand. The blackouts may be concentrated in a certain part of the grid, or it may be more widespread.

Rolling blackouts are far more common in parts of Africa, South Asia, and Latin America. Sometimes, rotating outages are scheduled for certain times of the day and the week, allowing people to plan ahead. However, the blackouts can happen without notice, especially when transmission frequency falls below accepted safe limits.

To prepare for a rotating outage, you should have an emergency plan in place. Your family may not all be in the same place when it happens, so you should all know what to do in case of a blackout. First, find a place where you will all meet. During rotating outages, local phone service may be intermittent, so try using an out of town contact to communicate with stranded family. It's also a good idea to have an emergency plan at work or school.

It's vital to consider the needs of your family before a rotating outage. Be sure to notify any caregivers about your emergency plan, and plan ahead for your pets as well. If anyone in your family uses medical equipment that depends on electrical power, notify your utility company. Most keep a list of customers that need power for medical reasons; ask them about alternative arrangements.

You should know whether or not your area is subject to rotating outages. Most last for about an hour before they shift to the next area. Typically, hospitals, airports, police and fire stations are exempt from blackouts, which can happen at any time and can also happen more than one time per day.

You should also learn about your local and state government's emergency plans for rotational outages. In an emergency, be sure to listen to the instructions provided by your local emergency management agency. Power companies usually try to warn customers when a rotational outage is happening, but that's not always possible.