Circuit restoration is the reestablishment of communication after it has been broken due to error, mechanical damage, or other issues. This applies to a wide variety of electrical circuits, including those used in telecommunications and the circuits that supply electrical power to customers of a utility. Utilities work to reduce circuit downtime and have a number of measures in place to address failing or broken circuits as quickly as possible. In some cases, they can act before customers notice a problem to restore power.
In telecommunications, failsafe mechanisms allow circuits to roll over to backups if they begin to falter. These can keep a phone call on the line even when the original circuit starts to cut out and can prevent loss of electric power. Circuits may lose connectivity for a variety of reasons, ranging from trees falling on a line to switching errors. In the event a circuit drops out entirely, the utility can work to restore communication with both automated and manual means.
Manual circuit restoration can become necessary in cases of extensive or complex damage. Systems may also need attention from a technician when they have been hacked or modified by an external source, as the utility company may need to reverse the damage before it can restore the connection. In some cases, workers need to travel to the field to address the problem at a junction box or in a length of cabling, in which case consumers may temporarily be without service.
Electric utilities use a variety of measures to control and switch circuits and to step in when circuit restoration may be necessary. They have procedures in place to rank customers by importance in the event of power outages or partial power failures. Lifesaving equipment and key government operations are typically first in line to reduce the risk of deaths or political disorder. The utility works down through a list of customers to restore power to as many as possible as quickly as possible.
Customers without power or phone service can typically get an estimate on how long circuit restoration will take. The utility bases this information on what is known about the problem and how long the repair work for similar problems usually lasts. Sometimes the utility gives a wide estimate for circuit restoration and tries to fix the problem well within that time. Underpromising by exaggerating the length of time needed provides the utility with some wiggle room and can increase customer satisfaction when the utility overdelivers by getting circuits back up early.