75 vs 90 degree

[mshields]

I need to a 2000A feeder from a service entrance switchboard to another switchboard. Will be specifying the usual suspects; GE, Eaton Schneider and Eaton. Can I safely assume that the terminations are rated for 90 degrees and that therefore I can use the 90 degree rating of the conductors; i.e. to keep the size of them to a minimum.

Thanks,

Mike

 

[augie47]

Are you going buss to buss or are there devices involved ?

 

[JFletcher]

I would not assume anything in this case... I would look up the specifications on the switchboards or place a call to the manufacturer.

if they are rated 90°, no problem. If not, use 90 degree C terminations on both ends and just run a little bit of up size wire from the switchboard to the terminations

 

[infinity]

Even with 90° C terminals the equipment itself would need to listed for 90° C as well. Except in some obscure equipment you're stuck with 75° C.

 

[electrofelon]

Even with 90° C terminals the equipment itself would need to listed for 90° C as well. Except in some obscure equipment you're stuck with 75° C.

If they were doing a tap or feed thru off a buss they could use 90 right?

 

[Glennsparky]

If they were doing a tap or feed thru off a buss they could use 90 right?

To rephrase what infinity said, read the equipment label or look up the listing in the UL white book. 90* C on preexisting lugs tells you nothing. Even for equipment that never had a label and was never listed by a NRTL, 90* C on the lugs is just the beginning. Were the lugs installed per their listing, according to manufacturer's instructions, etc.?

 

[kingpb]

You will not find LV, i.e. 600V or below terminations or equipment rated for 90 deg C. The are all 75 deg C rated. You can only use the 90 deg C column for cable derating purposes.

I spoke with and Eaton engineer about this a couple years ago, and he said that due to the complexity and money involved for design changes and testing required to go from 75 to 90, there is not enough push in the industry to do so, and therefore not likely to happen.

 

[Dale001289]

I need to a 2000A feeder from a service entrance switchboard to another switchboard. Will be specifying the usual suspects; GE, Eaton Schneider and Eaton. Can I safely assume that the terminations are rated for 90 degrees and that therefore I can use the 90 degree rating of the conductors; i.e. to keep the size of them to a minimum.

Thanks,

Mike

Only if the switchboard is rated over 1000V - see NEC 110.40 and IEEE C37