disconnecting means

[sahelrahman]

Hi
Can anyone pls tell me if a 45kVA 480v-208v remote transformer require a disconnecting means?

Thanks

 

[waross]

It depends.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[jmbelectrical]

Unfortunately, Bill's response is correct. As this is an international forum, without additional information - specifically, the electrical code (If there even is one) that you are required to adhere to, this is a rather difficult question to answer.

Having said that, assuming that you are designing to the 2011 (Or newer) National Electrical Code, NEC 450.14 requires a disconnecting means for any transformer that is not Class 2 or Class 3 rated. The disconnect is permitted to be within sight of the transformer or located remotely. If remotely, the disconnecting means must be lockable and the transformer must be labeled with the location of its associated disconnecting means.
Since you're required to provide primary-side overcurrent protection anyways, you can usually satisfy both of these requirements with the same device, be it a fused disconnect switch or a circuit breaker.