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Size of LV cables of a Transformer
2

Size of LV cables of a Transformer

Size of LV cables of a Transformer

(OP)
What determines the size of LV cables on a Transformer ?
Say on a 11000/415 volt 800 kVA, is it the conected load or the the actual kVA Rating?

RE: Size of LV cables of a Transformer

2
i always size the cable on the LV side of the transformer based on KVA rating and not on the connected load..

i always consider the future load growth which will be a problem if you size the cable on the present connected load only...


dydt

RE: Size of LV cables of a Transformer

(OP)
Dear dydt,

Many thanks for that answer, it was the answer I was hoping for.
I have read several books but cannot find a hard and fast answer to my question.
I was not sure if short circuit current came into the equation, but I shall use your solution.

Again many thanks,

Paul

RE: Size of LV cables of a Transformer

Paul,
I aggree with DYDT. Size to KVA rating.

RE: Size of LV cables of a Transformer

the short circuit rating will come into play when you select the protection settings.

RE: Size of LV cables of a Transformer

Consistent with views already stated, why would you want to restrict transformer loading via secondary bus/conductor sizing?  In most cases, that would seem like a false sense of economy.

RE: Size of LV cables of a Transformer

Hi,

Yep KVA it is!

Just keep in mind that laying conditions will affect current carrying capacity.

best of luck..

ADN

RE: Size of LV cables of a Transformer

Since we are on the subject:  What protects the cable on the secondary side???  Would it be the breaker on the HV side???  

Wirenut

RE: Size of LV cables of a Transformer

The main breaker or fuse your terminating your low voltage cable at, for overloads, and the primary and secondary protection for short circuits.

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