bundled conductor and temp calculations

[rickh]

When calculating the derating factor for more than 3 conductors and temperature variance. Which do you calculate first for the end result?

 

[lauraj]

The order doesn't matter. If I have 7 current carrying conductors, #6 THHN, in an ambient temperature of 33? C:

75A x .70 x .91 = 75A x .91 x .70

 

[Pierre C Belarge]

It does not matter which order you choose to perform first. Either way the answer will be the same.

 

[turtlejenn]

Rick,
seen this sitting for awhile,I'll jump...I know no hard & fast rule..The way I was taught is ampacity 310.16,then ajustment factor of 310.15(B)(2)(a) then temp. correction factors @ bottom of table 310.16

Always worked for me..

 

[Smart $]

Rick,
seen this sitting for awhile,I'll jump...I know no hard & fast rule..The way I was taught is ampacity 310.16,then ajustment factor of 310.15(B)(2)(a) then temp. correction factors @ bottom of table 310.16

Always worked for me..

I'm in agreement with the others. No particular order, as both are factor based.

However, if I were told one must precede the other, I would say ambient temperature adjustment comes first because it is part of the Table.

 

[ericsherman37]

Associative Property of Multiplication

The property which states that for all real numbers a, b, and c, their product is always the same, regardless of their grouping:
(a . b) . c = a . (b . c)

Associative Property of Addition

The property which states that for all real numbers a, b, and c, their sum is always the same, regardless of their grouping:
(a + b) + c = a + (b + c)

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