What is a Bay-o-net fuse?

Eaton’s Cooper Power series Bay-O-Net fuse offers a protection package for single- and three-phase transformers. The assembly combines the ease of hotstick operation with the safety of deadfront construction and is used with an isolation link to prevent line personnel from closing into a fault when replacing a blown Bay-O-Net link

Bay-o-net fuses are widely used in padmount transformers and are considered the industry standard for transformer fusing. These fuses are a type of expulsion fuse, which is commonly used in electrical distribution systems on utility poles and inside transformers.

Expulsion fuses, including bayonet fuses, have a thin, fusible element that melts when subjected to high current or temperatures. When the element melts, it creates an arc inside the fuse housing. The arc heat interacts with a special lining in the housing, generating gasses that fill the housing and quickly extinguish the arc, and prevent current flow.

Bay-o-net fuse core features：

1.A Bay-O-Net fuse is ideal for use in a two-fuse protection scheme with a current-limiting backup fuse. In this arrangement, secondary faults and overload currents are cleared by the Bay-O-Net fuse, and high level faults are cleared by the current-limiting fuse. The two fuses are connected in series, and are coordinated so that the current-limiting fuse operates only upon internal equipment failure

2.Bay-O-Net fuse not used in-series with a current-limiting fuse require an isolation link

3.Bay-O-Net fuses are comparable in cost to internal cartridge fuses but have the advantages of being field-replaceable. Bay-O-Net fuses can easily be coordinated with upstream devices

4.An isolation link provides extra protection during refusing and switching operations when used in series with a Bay-O-Net type fuse or MagneX Interrupter.

Classification of Bay-o-net fuse

Normally, Bay-o-net fuses are divided into three series:Current sensing,Dual sensing and Dual element.Below we will introduce the differences between these three types of Bay-o-net fuses.

1.Current sensing Bay-o-net fuse

Eaton protects both distribution apparatus from damaging currents and distribution systems from failed apparatus with its Cooper Power series

current sensing Bay-O-Net fuse link that is used in Eaton's Cooper Power series Bay-O-Net fuse assemblies.They are used on single-phase conventional and self-protected distribution transformers and other apparatus rated through 500 kVA, and on three-phase equipment through 1500 kVA.

A Bay-O-Net fuse is ideal for use in a two-fuse protection scheme with a current-limiting backup fuse. In this arrangement, secondary faults and

overload currents are cleared by the Bay-O-Net fuse, and high level faults are cleared by the current-limiting fuse. The two fuses are connected

in series, and are coordinated so that the current-limiting fuse operates only upon internal equipment failure. 

2.Dual sensing Bay-o-net fuse

Eaton protects both distribution apparatus from damaging currents and to protect distribution systems from failed apparatus with its Cooper Power series dual sensing Bay-O-Net fuse link that is used in Eaton's Cooper Power series BayO-Net fuse assemblies.

Dual sensing links sense not only secondary faults, excessive load currents and transformer faults, but also transformer fluid temperature. They will limit long-term transformer heating caused by overloads and high temperature environments.

3.Dual element Bay-o-net fuse.

Eaton protects both distribution apparatus from damaging currents and distribution systems from failed apparatus with its Cooper Power™ series dual element Bay-O-Net fuse link that is used in Eaton's Cooper Power series Bay-O-Net fuse assemblies.

Dual element links sense not only secondary faults, excessive load currents and transformer faults, but also transformer fluid temperature. They will limit long-term transformer heating caused by overloads and high temperature environments.

What is the difference between dual sensing and dual element fuses?

The Dual Sensing fuse is sensitive to both current and oil temperature, thus providing both overload and primary circuit protection. Dual Element combines the two. To avoid closing on a fault an Isolation Link or a current limiting fuse must be used in series with the Bayonet Fuse.

Summary:

Bay-O-Net fuses can be used on single-phase conventional and self-protected distribution transformers and on three-phase equipment.

Its ideal use is in a two-fuse protection scheme with a current-limiting backup fuse. In this arrangement, secondary faults and overload currents are cleared by the Bay-O-Net fuse, and high level faults are cleared by the current-limiting fuse. The two fuses are connected in series,and are coordinated so that the current-limiting fuse operates only upon internal equipment failure.If the Bay-O-Net fuse will not be used in series with a current-limiting fuse, an isolation link is required.

Bay-O-Net fuses are comparable in cost to internal cartridge fuses but have the advantages of being field-replaceable. Bay-O-Net fuses can easily be coordinated with upstream devices.