The term “dedicated circuit” is used in several different ways. Most commonly, it is used in reference to a phone or data line, or to an electrical circuit. In both cases, the idea is that it is a circuit set aside for a specific purpose, often with the implication that the use is either sensitive in nature or highly demanding, making it necessary to isolate the circuit used. Such circuits require some extra attention and care during the installation phase so that they are installed properly given the use they are intended for.
In electrical wiring, a dedicated circuit is set up with its own circuit breaker and intended for a single use. In some cases, a receptacle may be wired to it so that it can be connected to an appliance such as a stove or a refrigerator. In other cases, an appliance can be wired directly into the circuit, as is commonly seen with electrical water heaters.
This type of circuit is designed to ensure that it will not be overloaded by the appliance that draws power from it. Electrical appliances can use a great deal of energy, and running multiple appliances on the same circuit or loading several smaller items onto a circuit used to power an appliance can be dangerous. For example, if a stove and a hair dryer are powered on the same circuit, the circuit will probably blow because of the high energy demand. By dedicating a circuit, the supply of power will not be interrupted and operating conditions will remain safe.
Phone companies use dedicated circuits, also known as leased lines, to provide a direct hard connection for a specific purpose. Leased lines are often used for data lines, and some boast very high transfer rates because they are not used for anything else. This type of circuit can also be used for a phone line. It may be structured into the design of a phone exchange, or established in the form of a direct wired connection between two points.
This type of dedicated circuit can be quite costly for consumers, as it is costly for the phone company to operate. As a result, they are primarily used by large businesses, research facilities, and institutions that need secure or dedicated lines to operate. It is also possible to have multiple leased lines, as several may be needed for a large institution handling a very heavy load.