GB/T 2900.18-2008Electrotechnical terminology - Low voltage apparatus (English PDF)

3.1 Low-voltage apparatus

3.1.1 Low-voltage apparatus

It refers to electrical apparatus for make and break, protection, control or regulating action in circuits with a.c. 50Hz (or 60Hz), 1000V or below rated voltage and 1500V or below d.c. rated voltage.

3.1.2 Distributing apparatus

It refers to electrical apparatus mainly used for power distribution loop (circuit) for the purpose of protection, make and break, power supply transition or loading of circuit and equipment.

3.1.3 Control apparatus

It refers to electrical apparatus mainly used for controlling power receiving equipment to make it reach expected working state.

3.1.4 Switchgear and controlgear

It is the generic term of the combination of switching device and its associated control, measurement, protection and regulating equipment, and it also refers to the combination of such electrical apparatus and associated internal connecting lines, accessories, enclosure, supporting components, etc.

3.1.5 Switchgear

It is the generic term of the combination of switching device mainly used for power generation, power transmission, power distribution and electric energy conversion and its associated control, measurement, protection and regulating equipment. It also refers to the combination of such electrical apparatus and associated internal connecting lines, accessories, enclosure, supporting components, etc.

3.1.6 Controlgear

It is the generic term of the combination of switching device mainly used for controlling power receiving equipment and its associated control, measurement, protection and regulating equipment. It also refers to the combination of such electrical apparatus and associated internal connecting lines, accessories, enclosure, supporting components, etc.

3.1.7 Switching device

It refers to electrical apparatus used for making or breaking the current of one or more circuits.

3.1.8 Mechanical switching device

It refers to a switching device for closing and opening one or more circuits through separable contact.

Note: Mechanical switching device may be classified through the medium of contact closing and opening position, such as air, SF6 and oil.

3.1.8.1 Fixed trip mechanical switching device

It refers to the mechanical switching device with trip only in closed position.

3.1.8.2 Trip-free mechanical switching device

It refers to the mechanical switching device that the motional contact can return to and maintain in open position so long as opening (tripping) operation even though maintaining closing command after closing operation start.

Note: In order to guarantee to accurately break possibly existing current, the contact may be required to instantaneously reach the closed position.

3.1.9 Semiconductor switching device

It refers to a switching device making circuit current through controllable conductibility of semiconductor.

3.1.10 Air switching device

It refers to a switching device that the contact is opened or closed in free air.

3.1.11 Oil-immersed switching device

It refers to a switching device that the contact is opened or closed in oil.

3·1.12

Vacuum switching device

It refers to a switching device that the contact is opened or closed in vacuum.

3.1.13 Short circuit protective device; SCPD

It refers to electrical apparatus to protect circuit or circuit component against short-circuit current damage through breaking short-circuit current.

3.1.14 Control circuit device

Control circuit device

It refers to electrical apparatus used in switchgear and controlgear for control, signal and interlocking.

3.1.15 Indoor switchgear and controlgear

It refers to switchgear and controlgear may only be installed in building preventing wind, rain, snow, abnormal dust deposit, abnormal condensation, ice and sugar snow or in other rooms.

3.1.6 Outdoor switchgear and controlgear

It refers to switchgear and controlgear may be installed outdoors and can withstand wind, rain, snow, dust deposit, condensation, ice and sugar snow.

3.1.17 Fuse

It refers to electrical apparatus opening wired circuit and breaking power supply through fusing one or several specially designed corresponding components after a long enough time of current exceeding the specified value. The fuse includes all components consisting of integral electrical apparatus.

3.1.18 Enclosure

It refers to a component capable of providing a specified degree of protection to prevent certain external effect and prevent approaching and touching live parts and motion parts.

3.1.19 Integral enclosure

It refers to the enclosure consisting of a part of electrical apparatus.