90 degree or 75 degree

davejwalker

Member
Location
Wyoming
Occupation
Electrician, Electrical Estimator
The figure below comes from a Mike Holt training.
It is depicting a situation where the 90 degree conductor ampacity rating can be used in a circuit with 75 degree rated terminals
I am wondering if this same logic can be applied using a Burndy APY compression termination AYPO600
The pin portion of the connector would be considered 75° and from the compression point on would be considered 90°
Am I over thinking it?

1716995776968.png
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
In almost all cases the equipment is rated 75C so your final ampacity must be rated 75C. However, if you have to de-rate your conductor then you can start from the 90C rating of the conductor as long as the final ampacity is not greater than the 75C rating. 110.14(C)
 

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
The pin portion of the connector would be considered 75° and from the compression point on would be considered 90°
Am I over thinking it?
I'm guessing no. The idea in the graphic is that the heat generated in the smaller 90° C conductors will dissipate when it gets to terminations of the larger 75° C conductors through the heat sink effect. Running the conductors right up to the terminal with a pin adapter at their 90° C ampacity defeats that purpose.
 

jim dungar

Moderator
Staff member
Location
Wisconsin
Occupation
PE (Retired) - Power Systems
Breakers, and fusible switches, are UL tested with 4ft of NEC sized conductors.
This length allows for heat sink effect, as well as proving the conductors are held in the lugs during short circuit conditions.
 
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