I found this article on the web that discusses some more subtle distinctions: Hope this helps, Daniel Chartier.

UL1558 for switchgear and UL891 switchboard in North America.

In order to quench the arc that occurs on opening such a switch, special arcing horns are provided.

High Voltage Switchgear Indoor and Outdoor Switchgear Switchgear Equipment 1.

Switches 2. Fuses 3.

Circuit Breakers 4.

Protective Relays 5.

The switchgear devices and their assemblies are used in connection with the generation, transmission, distribution, and conversion of electrical energy.

Switches are used for opening and closing an electric circuit while fuses are used for over-current and short-circuit protection.

In such a way, every electrical device wants a switching and a protecting device.

Thus switchgear can be taken as a general term covering a wide range of equipment concerned with the switching, protection, and control of various electrical equipment.

Some equipment is meant for switching and not sensing the fault.

On the other hand, when a failure (e.g.

However, such switchgear cannot be used profitably on a high voltage system (33 kV) for two reasons.

When a short circuit occurs on the system, a heavy current flowing through the equipment may cause considerable damage.

It is because a circuit breaker can close circuits, as well as break them without replacement and thus has a wider range of use altogether than a fuse.

When a fault occurs on any part of the power system, they must operate to isolate the faulty section from the remainder circuit.

In case the electrical (or electronics) control fails, the necessary operation can be carried out through manual control.

They include most of the substation equipment such as minimum oil circuit breakers, bulk oil circuit breakers, air magnetic, SF6 gas-insulated, vacuum, and gas-insulated switchgear.

Although it may be capable of functioning in other conditions also.

So, special care to be taken during designing of high voltage switchgear.

Hence high voltage circuit breaker should have special features for safe and reliable operation.

Most of the time these circuit breakers remain at ON condition and may be operated after a long period of time.

So Circuit Breakers must be reliable enough to ensure safe operation, as when required.

The circuit breakers, isolators, transformers, bus-bars, and all other substation equipment occupy considerable space on account of large electrical clearance associated with high voltages.

In this type of construction, all live parts are completely enclosed in an earthed metal casing.

It includes switches, fuses, circuit breakers, relays, current transformer, and other equipment.

It can be used under full-load or no-load conditions but it cannot interrupt the fault currents.

This is particularly true for circuits of high voltage and large current capacity.

Electrical Switchboard Vs Switchgear