Electrical Switchgears Key Terms

Learn the language of electrical switchgears

By Howard Robertson

Electrical switchgears are essential to keep your trade moving with a dependable supply of electricity. You will need to keep the current flowing to your generator, motor and other machines. The term switchgear refers to the combination of electrical disconnects, fuses and/or circuit breakers that isolate electrical equipment from the power supply. Switchgears can de-energize equipment to allow work to be done and clear faults downstream. This guide covers some of the common terms you'll hear from switchgear manufacturers, such as "electrical fuses" and "circuit breakers."

Low-voltage switchgears

Low-voltage switchgears consists of circuit breakers, contact boards (that open or close the power supply), sensors (such as temperature sensors, limit and proximity switches) and disconnectors. Low-voltage switchgears control and protect processes.
Try: You can read through Schneider Electric’s (PDF) website for a technical article on low-voltage switchgears. Additionally, IEC, a service provider in the field of low-voltage switchgears and control gears, provides more information.

Gas-insulated switchgears (GIS)

Gas-insulated switchgears, or GIS, are an effective but costlier type of switchgears. A GIS uses pressurized sulfur hexafluoride (SF6) gas to insulate the conductors and contacts.
Try: TELSTAR, a manufacturer of high- and ultra-high vacuum systems for industrial applications, publishes detailed information on gas-insulated switchgears and their applications.

Electrical Fuses

In electrical engineering, a fusible link or a fuse is a type of over-current protection device. It consists of a metal wire that melts when current with more than a predetermined value flows, thus breaking the circuit in which it is connected. This protects the circuit's other components from damage due to excessive current.
Try: You can refer to www.electronics-manufacturers.com, an online resource, for detailed information on the different kinds of electrical fuses available.

Circuit breakers

A circuit breaker breaks the circuit and stops the current flow when the current exceeds a predetermined level. A circuit breaker trips to break the circuit and can be reset, whereas, a fuse melts and needs a replacement.
Try: Maintenance Resources, a monthly magazine, publishes detailed information on the different types of circuit breakers.

Magnetic circuit breakers

You can use magnetic circuit breakers to interrupt the magnetic circuit arc.
Try: Cold Sparks Services, an electrical service provider, publishes detailed information on magnetic circuit breakers. For the definition of the term "magnetic circuit breakers," you can refer to the glossary by American Crane and Equipment Corporation (ACECO).

Air circuit Breakers

An air circuit breaker uses compressed air to blow out the arc. Alternatively, it swings the contacts into a small, sealed chamber so that the displaced air blows out the arc.
Try: You can refer to the General Electric website for information on air circuit breakers.