When sizing conductors, can the 90C rating of a conductor be used only when derating for temperature, if not when can the ampacity rating for a cable rated at 90C be used?
110.14(C) Temperature Limitations. The temperature rating associated with the ampacity of a conductor shall be selected and coordinated so as not to exceed the lowest temperature rating of any connected termination, conductor, or device. Conductors with temperature ratings higher than specified for terminations shall be permitted to be used for ampacity adjustment, correction, or both.
There are at least two instances where a 90?C-rated conductor can be used at it's full ampacity rating. One such scenario is under 310.15(A)(2) Exception. The other is installations qualifying under 110.14(C)(2) for 600V and less. Only if identified otherwise is the any limitation for over 600V.When sizing conductors, can the 90C rating of a conductor be used only when derating for temperature, if not when can the ampacity rating for a cable rated at 90C be used?
Didn't say there was. Why do you bring this up in response to my post?There are no UL listed 600V max. overcurrent protective devices that can be used with conductors sized per the 90?C column
If I had intended to respond to your quote, I would have quoted you in my posting.Didn't say there was. Why do you bring this up in response to my post?
Didn't say there was. Why do you bring this up in response to my post?
If I had intended to respond to your quote, I would have quoted you in my posting.
OK... I have to apologize, I don't have a copy of your manual of posting etiquetteIf I had intended to respond to your quote, I would have quoted you in my posting.
This response is directed to all participants...If I had intended to respond to your quote, I would have quoted you in my posting.
There are at least two instances where a 90?C-rated conductor can be used at it's full ampacity rating. One such scenario is under 310.15(A)(2) Exception. The other is installations qualifying under 110.14(C)(2) for 600V and less. Only if identified otherwise is the any limitation for over 600V.
One debatedly practical application is to go from 75?C-rated size to 90?C-rated size conductor by joining circuit conductors in a terminal box with 90?C-rated terminations (i.e. terminal strips, splice blocks, etc.). Of course the enclosure itself also needs to be rated for 90?C or higher operationn.
Perhaps... but it answers the question?in some small way?posed in the OP; the question that everyone seems to dance around because it is, in many, but not all instances, impracticable, as you say.I do not see either of the two sections you mentioned as being practicable for the daily work we see 99% of the time.
I did not post to deny your post. I see so many who think the 90C column is the way to size conductors, that I am surprised. I just wanted to let others who are not too sure to be careful when choosing which column for the final determination of ampacity of conductors.
This response is directed to all participants...
Many visitors choose to view these forums in the "Linear" Display Mode. I do myself. However, aside from the OP, every post to the thread is in response to another. That post is the one in which you clicked the Quote or Reply button. Those that view these forums in "Hybrid" or "Threaded" Display Mode realize this.
PS: The Display mode can be changed via the "thread menu" at the upper right corner of the OP.
I believe the Display mode can be changed from the top of any page.PS: The Display mode can be changed via the "thread menu" at the upper right corner of the OP.
AFAICT, the option is only available on any individual "thread" page (exactly where I stated it is). Other pages, such as reply and thread lists do not have a "thread menu". Changing it in one thread changes it for subsequent visits (and perhaps refreshes) to any other thread until viewer changes it back.I believe the Display mode can be changed from the top of any page.
Okie-dokie!Full moon?:roll: