Feeder/Fuse Size

[Alwayslearningelec]

@ the 75 degree column two sets only good for 760A. Maybe they are using 90 degree column...................

 

[augie47]

What's your question.
240.4 allows an 800 amp breaker on conductors rated 760 amps as long as the load doesn't exceed 760.

 

[infinity]

@ the 75 degree column two sets only good for 760A. Maybe they are using 90 degree column...................

They're not using the90° C column, they're using the 75° C column and the next size up rule in 240.4(B) as Augie mentioned.

 

[Alwayslearningelec]

Ok i have to become familiar with that rule. Thought feeder ampacity always had to be greater than breaker size.

 

[Dennis Alwon]

@ the 75 degree column two sets only good for 760A. Maybe they are using 90 degree column...................

Would you please give more info when you ask a question. @ sets of what???? at least give the wire size and say whether copper or al. For the number of questions you ask it's the least you could do.

 

[Alwayslearningelec]

Would you please give more info when you ask a question. @ sets of what???? at least give the wire size and say whether copper or al. For the number of questions you ask it's the least you could do.

Excuse you...wire size and sets given.

 

[Dennis Alwon]

My apologies.. I did not click on the pic- I thought that was the entire pic

 

[paulengr]

Motor breakers are sized 250% of FLA.

Transformers are “oversized”.

The overcurrent protection is based on the load and so is the wiring. The two are not necessarily related. For instance there is the next size up rule and tap rules.

 

[Alwayslearningelec]

My apologies.. I did not click on the pic- I thought that was the entire pic

I apologize as well. I know I ask a lot of question and must be a PIA. Sorry.

 

[electrofelon]

I apologize as well. I know I ask a lot of question and must be a PIA. Sorry.

I think generally most of us don't have a problem with lots of questions, what is frustrating is poor illegible drawings, lack of details, vagueness.

 

[Alwayslearningelec]

I think generally most of us don't have a problem with lots of questions, what is frustrating is poor illegible drawings, lack of details, vagueness.

Understood