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    310.16

    When sizing conductors and temp ratings at terminals on both ends are 90 degree you can use 90 degree column correct?

    Sent from my SM-N960U using Tapatalk

    #2
    Originally posted by mstrlucky74 View Post
    When sizing conductors and temp ratings at terminals on both ends are 90 degree you can use 90 degree column correct?

    Sent from my SM-N960U using Tapatalk
    That's a big maybe. If you are connecting to, say, a breaker, just because it has a 90 degree terminal does not make it a 90 degree device. Very little equipment is rated for 90 degree terminations.

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      #3
      Originally posted by mstrlucky74 View Post
      When sizing conductors and temp ratings at terminals on both ends are 90 degree you can use 90 degree column correct?

      Sent from my SM-N960U using Tapatalk
      Short answer is no. You would use the 75° C ampacity. You could use the 90° ampacity for derating purposes.
      Rob

      Moderator

      All responses based on the 2017 NEC unless otherwise noted

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        #4
        If the short answer is no, then the long answer is yes. You could certainly introduce 90deg splice blocks into a feeder run to use the 90deg conductor ampacity in the middle section, between the 90deg terminations.

        In other words, 75deg ampacity at each end and 90deg ampacity in the middle.

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          #5
          Originally posted by mstrlucky74 View Post
          When sizing conductors and temp ratings at terminals on both ends are 90 degree you can use 90 degree column correct?

          Sent from my SM-N960U using Tapatalk
          The key here is whether you truly have 90C terminations. Most 600 volt and less equipment you will be limited to 75C unless you did something like david L mentioned and added 90 C splicing methods somewhere in between original points of termination.
          I live for today, I'm just a day behind.

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            #6
            Originally posted by david luchini View Post
            If the short answer is no, then the long answer is yes. You could certainly introduce 90deg splice blocks into a feeder run to use the 90deg conductor ampacity in the middle section, between the 90deg terminations.

            In other words, 75deg ampacity at each end and 90deg ampacity in the middle.
            you would need a larger gauge 75deg conductor at each end

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              #7
              Originally posted by texie View Post
              That's a big maybe. If you are connecting to, say, a breaker, just because it has a 90 degree terminal does not make it a 90 degree device. Very little equipment is rated for 90 degree terminations.
              Can you show me an example of this? If the breaker has 90 degree terminations it seems like it would be that you would use the 90 degree table of 310.16 per 110.14(C)


              I know what I don't know, and I know where to go to find it!

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                #8
                Originally posted by Strathead View Post
                Can you show me an example of this? If the breaker has 90 degree terminations it seems like it would be that you would use the 90 degree table of 310.16 per 110.14(C)
                110.14(C) uses the term "equipment" in limiting the ampacity based on termination ratings. The lugs might well be rated 90° but the equipment is most often not.
                At my age, I'm accustomed to restaurants asking me to pay in advance, but now my bank has started sending me their calendar one month at a time.

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                  #9
                  Originally posted by augie47 View Post
                  110.14(C) uses the term "equipment" in limiting the ampacity based on termination ratings. The lugs might well be rated 90° but the equipment is most often not.
                  Doesn't the breaker have the termination rating on it?


                  I know what I don't know, and I know where to go to find it!

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                    #10
                    Originally posted by Strathead View Post
                    Doesn't the breaker have the termination rating on it?
                    Everyone I ever looked at did and the two here on my desk do (60-75°)
                    At my age, I'm accustomed to restaurants asking me to pay in advance, but now my bank has started sending me their calendar one month at a time.

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                      #11
                      Originally posted by Strathead View Post
                      Doesn't the breaker have the termination rating on it?
                      If it is a removable type of lug, there is pretty good chance the lug itself is marked 90C, but that is a stand alone marking. The breaker itself is going to be rated (and marked somewhere) for 75C. Doesn't matter if you attached a lug with stand alone rating of 150C, it still is only good for 75C when attached to the breaker, and for that matter the 90C conductor landed in it is still only good for 75C ampacity as well, at that termination. You can still make ampacity adjustments based on the 90C insulation rating.
                      I live for today, I'm just a day behind.

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                        #12
                        Originally posted by augie47 View Post
                        Everyone I ever looked at did and the two here on my desk do (60-75°)
                        Right so I don't understand the issue. The terminations are rated 75 so that is the column. If it was rated 90 you would use the 90.


                        I know what I don't know, and I know where to go to find it!

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                          #13
                          Originally posted by kwired View Post
                          If it is a removable type of lug, there is pretty good chance the lug itself is marked 90C, but that is a stand alone marking. The breaker itself is going to be rated (and marked somewhere) for 75C. Doesn't matter if you attached a lug with stand alone rating of 150C, it still is only good for 75C when attached to the breaker, and for that matter the 90C conductor landed in it is still only good for 75C ampacity as well, at that termination. You can still make ampacity adjustments based on the 90C insulation rating.
                          texie didn't say lug, he said 90 terminal. I get it. My original intent wasn't to be difficult it was to find out if I needed to learn something. I didn't. It is as I understood it, that is fine.


                          I know what I don't know, and I know where to go to find it!

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                            #14
                            As others have pointed out, I think the confusion comes from the fact that a lot of terminals (ie: the actual 'lug' where you connect the wire) are rated at 90° which lead some to feel they are ok with a 90° ampacity.
                            At my age, I'm accustomed to restaurants asking me to pay in advance, but now my bank has started sending me their calendar one month at a time.

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                              #15
                              Some terminations are 90C however the equipment is rated 75C therefore you have to use the 75C rating. 90C is used for de-rating or as in the case below


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