PT secondary fuse selection 2

[SJBatTCE]

Can anyone explain the basis for selecting a PT fuse(or VT as some may call it) for the secondary winding?

Thanks. To whoever answers this... YOU RULE! Heh

 

[scottf]

Fuses are placed in the VT secondary circuit to guard against the secondary of the VT being shorted if there is a fault in the secondary circuit, between the fuse and the connected equipment.

The rating of the fuse should ideally be less than the thermal burden of the VT being protected. Take the themal burden divided by the rated secondary voltage to get the fuse rating. Non time delay fuses are generally used for this application.

It is best to place the fuses in the VT terminal box, but they are most commonly placed in the 3-phase junction box, normally mounted on the pedestal of the center phase.

If you have a VT with a tapped secondary, the fuse should be placed in the non-polarity lead, i.e. you don't need to have a fuse on each terminal.

Hope this helps.

 

[SJBatTCE]

There's your star,... YOU RULE (I always keep my promises)

 

[scottf]

Glad to be of help.