Transformer at Sub-Fed Bldg. - Disconnect Required?

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32Lateralus

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Location
West Coast
Occupation
Electrical
I have a scenario where we are receiving 480V power from another bldg on site. However, our bldg only needs 208V. Our bldg is also divided in two sections (A and B, each with it's own 208V panel).

  1. Would I need a disconnect BEFORE my transformer at my bldg?
  2. Or, could I hit the 480-208V transformer, double-tap into disconnect A and B, then feed the panel is each area.
  3. Are these main disconnects labelled as "service disconnects", even though they are downstream of the actual 'service'? I don't see "markings" section in 225 Part II which is bldgs supplied by a feeder that describes what these are to be called.

Essentially, I will always need the disconnects after the xfmr because of distance to the panels A and B, Im just not sure if a disconnect is required prior to the transformer (does 230.82 apply here?) and how to label the disconnect(s).

Thanks!
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
Transformer would be just outside the bldg
Then, it would be my opinion that this would be covered by 450.14 and that permits a remote disconnect if it is lockable in the open position and the location of the remote disconnect is indicated on the transformer.
 
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