This Isolation Links Can Become A Transformer 'invisible Bodyguard?

In cases where the transformer is relatively small and low voltage, and the available short circuit current isalso relatively low, bayonet fuses by themselves may be able to provide a suficient range of overcurrent protection without the addition of current limited fuse.

In these instances, isolation links must be used in coniunction with bayonet fuses to create a physical break in the circuit in the event of a transformer failure to preventelectrical workers from mistakenly re-energizing a failed transformer by replacing the bayonet fuse.

Isolation links and fuses both break a circuit, but they work differently: Fuses protect the system by safely cutting off high current during a fault (they have "interrupting capacity").

Isolation links do not protect against overcurrent-they only melt when a transformer fails, disconnecting it to prevent further damage. Because isolation links can't stop high currents like fuses, they must only be used where the fault current is within the fuse's safe limit (AIC rating).

Transformer engineers carefully choose protection devices to keep the system safe while ensuring reliable operation. A well-designed fuse system uses each component for its specific role.

Why are isolation links used with Bay-O-Net fuse links?

The isolation link is used in series with Bay-O-Net fuse link to provide extraprotection for transformer.lsolation linksare not fuses and do not have aninterrupting rating. During a low impedancetransformer failure, the isolation link willmelt so that the opened primary circuit of afailed transformer cannot be re-energizedby the utility line crew.The design of the isolation link protects thelink element from handling damage thatcan cause nuisance open circuits inside thetransformer.
The isolation Links are designed to bebolted directly to the lower connection tabof the Bay-O-Net fuse holder in seriesbetween the primary transformer bushingand primary coil.