Transformer secondary length

[electricelmo]

I have spent part of the weekend trying to find in the code book about the length of wire for the secondary condutors out of the transformer. Our local AHJ claims that on are transformer 150 KVA 480 to 208/120 wye we can only have leads that are 10 feet long, we have hung transformers by bar joist and came down to panels 25 feet below. The 480 side is fused as per code. Is this a new rule are something we have overlooked in the past? Are is he making a a new rule of his own.

 

[billsnuff]

240.21 in '08 nec

 

[augie47]

There are diffferent specifics on the 25 ft and 10 ft tap rule.
You might review 240.21(C) on transformer taps to see if your 25 ft
tap meets all the requirements. (Industrial vs non-insdustrial, terminated in a single protection means vs. multiple means)

 

[infinity]

Take a look at 240.21(C)(6). You can up to 25' if you meet those three conditions.

 

[jim dungar]

Is this a new rule are something we have overlooked in the past?

No, it has been in the code for several decades now, although there was some tweaking done around 2002.