Nec 450.5

[LYLE2231]

Friends, would NEC 450.5 (A) (2) be the correct article to apply to calc OCP for 30kva dry transformer?

 

[raider1]

Friends, would NEC 450.5 (A) (2) be the correct article to apply to calc OCP for 30kva dry transformer?

Most likely not unless you are using one of the configurations mentioned in 450.5.

450.5 is for autotransformers, which have a common winding.

For a standard dry type transformer look at 450.3 for your overcurrent protection requirements.

Chris

 

[steve66]

I agree with Raider. But don't forget you also have to protect the conductors. So 240.21 will also come into play.

 

[raider1]

I agree with Raider. But don't forget you also have to protect the conductors. So 240.21 will also come into play.

Good point, a lot of times the fact that 450.3 only deals with overcurrent protection of the tranformer itself is overlooked.

Chris