Transformer Primary Conductors

[david luchini]

240.4(F) says the secondary conductors of a wye transformer cannot be considered as being protected by a primary side overcurrent device. 240.21(B)(3) is about primary side conductor protection (i.e. not having a dedicated primary protective device).

Yes, thanks, that's exactly my point.

How would you guys address Art 450 table 450.3(B) where you are allowed to size the primary protection up to 250%?

The question was about primary protection and conductors when using a Tap Supplying a Transformer from 240.21(B)(3). The question wasn't about protecting the secondary conductors, as the secondary conductors would be protected by the secondary OCPD.

for the transformer secondary protection where you may be able to apply the distance from the 250% primary to the 125% secondary breaker?