L LYLE2231 Member Jan 6, 2011 #1 Friends, would NEC 450.5 (A) (2) be the correct article to apply to calc OCP for 30kva dry transformer?
Friends, would NEC 450.5 (A) (2) be the correct article to apply to calc OCP for 30kva dry transformer?
raider1 Senior Member Staff member Location Logan, Utah Jan 6, 2011 #2 LYLE2231 said: Friends, would NEC 450.5 (A) (2) be the correct article to apply to calc OCP for 30kva dry transformer? Click to expand... 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
LYLE2231 said: Friends, would NEC 450.5 (A) (2) be the correct article to apply to calc OCP for 30kva dry transformer? Click to expand... 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 Senior Member Location Illinois Occupation Engineer Jan 6, 2011 #3 I agree with Raider. But don't forget you also have to protect the conductors. So 240.21 will also come into play.
I agree with Raider. But don't forget you also have to protect the conductors. So 240.21 will also come into play.
raider1 Senior Member Staff member Location Logan, Utah Jan 6, 2011 #4 steve66 said: I agree with Raider. But don't forget you also have to protect the conductors. So 240.21 will also come into play. Click to expand... Good point, a lot of times the fact that 450.3 only deals with overcurrent protection of the tranformer itself is overlooked. Chris
steve66 said: I agree with Raider. But don't forget you also have to protect the conductors. So 240.21 will also come into play. Click to expand... Good point, a lot of times the fact that 450.3 only deals with overcurrent protection of the tranformer itself is overlooked. Chris