temp. rating

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jumathum

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I have XHHW-2 type wire that per the NEC is rated at 90 degrees. Does the breaker that I am landing this wire to also need to be rated at 90 degrees to use the 90 degree ampacity?
 

Volta

Senior Member
Location
Columbus, Ohio
I have XHHW-2 type wire that per the NEC is rated at 90 degrees. Does the breaker that I am landing this wire to also need to be rated at 90 degrees to use the 90 degree ampacity?

Yes. 110.14(C) This will include the breaker, load equipment, lugs, splices, bushings, everything in the length of that conductor.
 
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bob

Senior Member
Location
Alabama
I have XHHW-2 type wire that per the NEC is rated at 90 degrees. Does the breaker that I am landing this wire to also need to be rated at 90 degrees to use the 90 degree ampacity?

Yes. You may use the 90C rating for derating the conductor or temperature adjustments.
 

jim dungar

Moderator
Staff member
Location
Wisconsin
Occupation
PE (Retired) - Power Systems
I have XHHW-2 type wire that per the NEC is rated at 90 degrees. Does the breaker that I am landing this wire to also need to be rated at 90 degrees to use the 90 degree ampacity?
Be aware, there are no UL listed breakers or fusible switches that can be used with the 90?C ampacities. Even though some equipment requires 90?C insulation the conductors must be sized at least as large as required under thee 75?C column.
 

Smart $

Esteemed Member
Location
Ohio
I have XHHW-2 type wire that per the NEC is rated at 90 degrees. Does the breaker that I am landing this wire to also need to be rated at 90 degrees to use the 90 degree ampacity?

"SQD has a good PDF in their site, that explains this very well."

A clip from said document....

90Cexample.gif


Link to document: http://ecatalog.squared.com/pubs/Electrical Distribution/0110DB9901R2-02.pdf
 

Rockyd

Senior Member
Location
Nevada
Occupation
Retired after 40 years as an electrician.
Where would 90'C be a typical installation in the wiring methods under 600 volts? I can see using the column for the derate, but thought most 90 degree equipment was for over 600 volt for typical installation (providing it is rated for the activity)(110.40)
 

Smart $

Esteemed Member
Location
Ohio
Where would 90'C be a typical installation in the wiring methods under 600 volts? I can see using the column for the derate, but thought most 90 degree equipment was for over 600 volt for typical installation (providing it is rated for the activity)(110.40)
No such thing as a typical 90?C-rated installation under 600 volts, that I'm aware of.
 
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