"Good engineering practice" Article in the NEC

[egurdian3]

I'm trying to back up the phrase "Good engineering practice recommends not to load electrical equipment beyond 80% of full capacity". Which article has this requirement?
Thanks.

 

[charlie b]

No such requirement exists in the NEC.

 

[ron]

If you looked, you could find something in the NEC about sizing circuits / feeders for continuous loads at 125% (inverse of 80%).

You could also probably find something in UL489 for molded case breakers (I suspect) about loading them at 80% continuous load.

But as Charlie said, so such requirement as you have requested.

 

[egurdian3]

Thanks guys. I guess 220.87 is as close as it gets to saying it.

 

[tom baker]

And see section 90.1(B) and its IN

 

[charlie b]

Thanks guys. I guess 220.87 is as close as it gets to saying it.

You lost me there. That article does not address your question at all.

 

[don_resqcapt19]

Take a look at 210.19(A)(1) and 215.2(A)(1). Both require conductors to have an ampacity at least equal to 100% of the continuous load plus 125% of the non-continuous load.