An electric switchboard is a piece of equipment that distributes

electric power Electric power is the rate of transfer of electrical energy within a electric circuit, circuit. Its SI unit is the watt, the general unit of power (physics), power, defined as one joule per second. Standard prefixes apply to watts as with oth ...

from one or more sources of supply to several smaller load circuits. It is an assembly of one or more panels, each of which contains switching devices for the protection and control of circuits fed from the switchboard. Several manufacturers make switchboards used in industry, commercial buildings, telecommunication facilities, oil and gas plants, data centers, health care, and other buildings, and onboard large ships. A switchboard is divided into different interconnected sections, generally consisting of a main section and a distribution section. These two sections are sometimes replaced by a combination section, which is a section that can fulfill the roles of both of the aforementioned sections. Switchboards can also sometimes come with an auxiliary section that is used to house devices that cannot be housed in the same section as other devices.

Definition

The U.S.

National Electrical Code The National Electrical Code (NEC), or NFPA 70, is a regionally adoptable standard for the safe installation of electrical wiring and equipment in the United States. It is part of the National Fire Code series published by the National Fire Prote ...

(NEC) defines a switchboard as "a large single panel, frame, or assembly of panels on which are mounted, on the face, back, or both, switches, over-current and other protective devices,

buses A bus (contracted from omnibus, with variants multibus, motorbus, autobus, etc.) is a motor vehicle that carries significantly more passengers than an average car or van, but fewer than the average rail transport. It is most commonly used ...

, and usually instruments". The role of a switchboard is to allow the division of the current supplied to the switchboard into smaller currents for further distribution and to provide switching, current protection and (possibly) metering for those various currents. In general, switchboards may distribute power to transformers, panelboards, control equipment, and, ultimately, to individual system loads.

Components

Inside a switchboard there will be one or more busbars. These are flat strips of copper or aluminum, to which the switchgear is connected. Busbars carry large currents through the switchboard and are supported by insulators. Bare busbars are common, but many types are now manufactured with an insulating cover on the bars, leaving only connection points exposed. In a modern switchboard, the operator is protected from

electrical injury An electrical injury (electric injury) or electrical shock (electric shock) is damage sustained to the skin or internal organs on direct contact with an electric current. The injury depends on the density of the current, tissue resistance an ...

by metal-enclosed circuit breakers, switches, and

fuses Munitions, Fuse or FUSE may refer to: Devices * Fuse (electrical), a device used in electrical systems to protect against excessive current ** Fuse (automotive), a class of fuses for vehicles * Fuse (hydraulic), a device used in hydraulic systems ...

. There may also be instruments and controls for the supply of electricity to the switchboard. For example, a switchboard for a bank of

electrical generator In electricity generation, a generator, also called an ''electric generator'', ''electrical generator'', and ''electromagnetic generator'' is an electromechanical device that converts mechanical energy to electrical energy for use in an extern ...

s, especially

frequency Frequency is the number of occurrences of a repeating event per unit of time. Frequency is an important parameter used in science and engineering to specify the rate of oscillatory and vibratory phenomena, such as mechanical vibrations, audio ...

would have control of

AC power In an electric circuit, instantaneous power is the time rate of flow of energy past a given point of the circuit. In alternating current circuits, energy storage elements such as inductors and capacitors may result in periodic reversals of the d ...

and load sharing, and instruments for frequency, voltage, current, and energy, with perhaps a synchroscope. A main switchboard is a large electrical switchboard that connects to the grid and distributes power to other smaller switchboards on the site.

References

External links

* {{Commons category-inline, Switchboards Electrical components Switches

Definition

Components

See also

References

External links