90 Degree Table

[kenaslan]

Is there any reason I cannot use the 90 Degree table to size wire for an underground feeder run. 1600A 4 sets of 500. Terminations are high press lugs bolted to bussbar at both ends. Terminations are rated at 90 Degrees C

Ken
ACADMEP Test Dummy

 

[haskindm]

IF the terminations (at both ends) are rated 90 degrees, and IF the equipment is rated 90 degrees, and IF the conductor is rated 90 degrees then you may use the 90 degree column. Where is the overcurrent protection? I am not aware of any circuit breakers rated for 90 degree terminations, but then I am not aware of allot of things...

 

[bphgravity]

Ken,

Regardless of the code for a moment, do you think operating conductors and equipment and cables at 90 degrees is a good design?

 

[Dennis Alwon]

Ken,

Regardless of the code for a moment, do you think operating conductors and equipment and cables at 90 degrees is a good design?

I am not trying to challenge that thought but I am curious as to why. If you can operate equipment rated 75C at it's max why not 90C?

 

[kenaslan]

Its what the utility wants. It is only a 150KVA transformer feeding a 1600A fused switchgear. I originally specd 6 sets of 400Al but the utility company in all their wisdom decided to do what utility companys do and installed 4 sets of 500 Cu

It would be so much easier to install what is specd in the first place

 

[kingpb]

Utilities are not bound by NEC restrictions. They get what they want.

 

[kenaslan]

Can anyone tell me why even include the 90 degree C table when 75 degrees is the max I ever spec out anyway. I have yet to see equipment rated at 90

 

[bphgravity]

For the purposes of derating.