Transformer location

[Steviechia2]

I am installing a 75kva transformer on top of a (2nd floor) free standing office inside of a garage/steel building. I have all the clearances permitted by the code and manufacturer all around the transformer.
Question-There is no staircase and the only way to the tranny is by ladder. I see no code that says I need a staircase.Am I correct?

 

[augie47]

You are corrrect

 

[Steviechia2]

Thanks!
Another Question
My primary ocpd is less than 125% so I have protection for my secondary windings.
Can I install my fused disconnect protecting secondary conductors and machine anywhere on the secondary side of transformer?

 

[augie47]

Thanks!
Another Question
My primary ocpd is less than 125% so I have protection for my secondary windings.
Can I install my fused disconnect protecting secondary conductors and machine anywhere on the secondary side of transformer?

Before I commit, what is primary/secondary voltage and your secondary wire size ?

 

[hurk27]

Thanks!
Another Question
My primary ocpd is less than 125% so I have protection for my secondary windings.
Can I install my fused disconnect protecting secondary conductors and machine anywhere on the secondary side of transformer?

If this is for Supervised Industrial Installations then within 100' if you meet all the requirements in 240.92(C)(1)(1) for Short-Circuit and Ground-Fault Protection. and 240.92(C)(1)(2) for Overload Protection.

Other wise if not Supervised Industrial Installation then you will have to follow requirement in 450.3 and 240.21(C)

 

[hurk27]

I am installing a 75kva transformer on top of a (2nd floor) free standing office inside of a garage/steel building. I have all the clearances permitted by the code and manufacturer all around the transformer.
Question-There is no staircase and the only way to the tranny is by ladder. I see no code that says I need a staircase.Am I correct?

Actually 450.13 allows exactly what you propose as long as the roof of this office is capable of supporting the load of the trany:

(A) Open Installations. Dry-type transformers 600 volts,
nominal, or less, located in the open on walls, columns, or
structures, shall not be required to be readily accessible.

Just make sure you get something in writing that the roof is capable of supporting it to cover your butt as you wouldn't want to be liable if it ever come crashing down through the roof and hurts someone.

 

[Steviechia2]

Before I commit, what is primary/secondary voltage and your secondary wire size ?

It's an existing tranny that we are moving . primary 208v 3phase(1/0 cu thhn) stepping up to secondary 480v (#2 cu thhn)

 

[Steviechia2]

It's an existing tranny that we are moving . primary 208v 3phase(1/0 cu thhn) stepping up to secondary 480v (#2 cu thhn)

With 150 amp ocpd in primary

 

[augie47]

You have 3 phase primary and 3 phase secondary with a ratio of 1/2.3.
If I did my math right (the calculation on that ratio are always tricky to me) , your secondary conductors are protected by your primary device.