primary disconnect required in sight for MV transformer?

[malachi constant]

We have an existing installation where the utility brings 13.8kV into the building. From there we have a lineup of MV switches that distribute out to transformer vaults within the facility (all one building, not a campus). These vaults contain (3) 1P cans that we are replacing with dry type 13.8k:208V equipment. Do these need to have additional primary protection within the vault (i.e. in sight of the transformer), or does the primary switch back at the service suffice? A question from a vendor has got me looking to verify, but I haven't found anything requiring it in NEC 240 or 450. Thanks!

 

[electrofelon]

We have an existing installation where the utility brings 13.8kV into the building. From there we have a lineup of MV switches that distribute out to transformer vaults within the facility (all one building, not a campus). These vaults contain (3) 1P cans that we are replacing with dry type 13.8k:208V equipment. Do these need to have additional primary protection within the vault (i.e. in sight of the transformer), or does the primary switch back at the service suffice? A question from a vendor has got me looking to verify, but I haven't found anything requiring it in NEC 240 or 450. Thanks!

See 450.3(A) for transformer protection requirements and 450.14 for disconnecting means.

 

[malachi constant]

450.3(A) transformers over 1000V, OCPD shall be per table 450.3(A).
-->Table 450.3(A), max primary protection over 1000V, fuse rating = 300%. Note 1 is regarding if not a standard size than round up.
I don't see anything there that requires this be in the same room.

450.14 disconnecting mean. Transformers shall have a disconnecting means located either in site of the transformer or in a remote location. When in a remote location the disconnecting means shall be lockable in accordance with 110.25, and its location shall be field marked on the transformer.

So I think that answers my question - we are good here. I may be able to make it fit and will make sure the Owner is in the loop on making the decision. Seems like a reasonable enough safety precaution.