Ambient temperature

[WMBELEDES]

How should I calculate ambient temperature of a wire if it starts in an oven and ends in an electrical enclosure?
EX:
Conductor runs 10 feet in a 400°f oven and then 40 feet thru a room that is 100°f then 10 feet in an enclosure that is 105°f.
Is it as simple as averages? 150.8°f

Wire is rated for the worst environment 400°f, terminals at that location is rated accordingly. Terminals in the electrical enclosure are rated for 75°c (167°f)

Bill

 

[gadfly56]

How should I calculate ambient temperature of a wire if it starts in an oven and ends in an electrical enclosure?
EX:
Conductor runs 10 feet in a 400°f oven and then 40 feet thru a room that is 100°f then 10 feet in an enclosure that is 105°f.
Is it as simple as averages? 150.8°f

Wire is rated for the worst environment 400°f, terminals at that location is rated accordingly. Terminals in the electrical enclosure are rated for 75°c (167°f)

Bill

So it looks like you did a weighted average. I think that would be OK if you assume that wire resistance is linear over the temperature range in question.

 

[Dennis Alwon]

IMO, you would be okay with the 400 degree ampacity.

(2) Selection of Ampacity. Where more than one ampacity
applies for a given circuit length, the lowest value shall be used.
Exception: Where different ampacities apply to portions of a circuit, the
higher ampacity shall be permitted to be used if the total portion(s) of
the circuit with lower ampacity does not exceed the lesser of 3.0 m
(10 ft) or 10 percent of the total circuit.

 

[Dennis Alwon]

Wording for the 2014

(2) Selection of Ampacity. Where more than one ampacity
applies for a given circuit length, the lowest value shall be
used.
Exception: Where two different ampacities apply to adjacent
portions of a circuit, the higher ampacity shall be
permitted to be used beyond the point of transition, a distance
equal to 3.0 m (10 ft) or 10 percent of the circuit
length figured at the higher ampacity, whichever is less.