Current limiting fuse types

Current limiting fuse, normally we call HRC fuse, or Medium Voltage fuse. It can be devided to types as below:

1, Base on Voltage:

 There is 3.6KV, 7.2KV, 12KV, 15.5KV, 17.5KV, 24KV, 36KV, 40.5KV level fuse;

2, Base on Protection devices:

1), Transformer protection Fuse: : 12TDLEJ63, SDLDJ-12KV/63A;

2), Motor circuit protection fuse: 7.2CAV10

3), Potential Transformer Medium Voltage Fuses: XRNP-12

4), Current limiting fuse links for use in oil switchgear: 3.6OEFMA100

3, Base on protection type, medium voltage fuse is split into three internationally recognised types: 

1), Back-up

(or sometimes called partial range), fuselinks, which will interrupt any current from their rated Breaking capacity down to a Minimum breaking current, specified by the manufacturer. 

2), General purpose 

MV Fuse links will interrupt all currents that will melt the elements within one hour. 

3), Full range 

MV Fuse links can interrupt any current below the rated Breaking capacity that melts the fuse elements satisfactorily.

4, Base on industrial standard:

HRC fuse are approved for use around the world and meet agency requirements and international standards: IEC, VDE, DIN, UL, CSA, BS and others.

1), IEC fuse:  3.6WDOSJ100, 7.2TDLSJ50, 17.5TDMEJ31.5;

2), DIN/VDE standard fuse link:  12TDLEJ50, 24TDMEJ31.5; 

3), British Standard fuse link: 3.6WDFHO100; 7.2WFNHO160; 

4), USA standard medium voltage fuse link:  2.75VFRHA6R, 5.5VKNHA12R;

What is NON current limiting fuse?

Essentially, non-current limiting fuse links have short elementsand incorporate some means of lengthening the arc after theelement melts, extinguishing the arc and preventing re-ignition.These are known as expulsion fuse links. Expulsion fuse links are an effective way of protecting overheaddistribution lines and transformers. They are designed for outdooruse only and comprise a tin or copper fuse element in series witha flexible braid in a tube. The tube forms one side of a triangle,with a latched connection at the top and a hinge at the bottom.The braid emerges from one end of the fuse link and is held intension by a spring downwards under gravity. Under fault conditions, the fuse link swings downwards, the arc is lengthened,extinguished and prevented from restriking.

How to test current limiting fuse?

Each Current limiting fuse is tested at highest system voltage and approved by the UK Electricity Association approvals panel.

You cannot test the electrical performance with the special testing equipment.

But you can test the fuse resistance. and ask Bussmann for the final inspection report for reference.