2008 EXAM PREP BOOK ERROR?

[bbilotta]

Can anyone tell me if the temperature correction examples on pages 176 and 177 of the 2008 exam prep book are known errors? Page 176 references a correction factor of .71 for 60*C, the correct factor should be .77 according to NEC 2008 as well as 2011. Page 177 references a correction factor of .91 for a 100*F example while the 08 and 11 NEC show the correction factor to be 1.00 for 96-104*F. Prepping for a test next week and just want to make sure i'm not missing something.

 

[PEDRO ESCOVILLA]

whos book are you referring to? got a title and author?

 

[Dennis Alwon]

The correction factors are based on temperature so it is hard to follow when you say 60C without a temp. That being said I don't see a .77 as a correction factor under 60C--- .71 is correct.

 

[david luchini]

The correction factors are based on temperature so it is hard to follow when you say 60C without a temp. That being said I don't see a .77 as a correction factor under 60C--- .71 is correct.

I think he meant 60C as the ambient temp, not the insulation rating. For a 90C conductor, 0.71 would be right for a 60C ambient, and 0.91 would be right for a 104F ambient.

He appears to be reading Table 310.20 - "Supported on a messenger" (NEC 2008) to get 0.77 for 60C ambient and 1.00 for 100F ambient, rather than Table 310.16.

 

[Dennis Alwon]

I think he meant 60C as the ambient temp, not the insulation rating.

Of course- that makes sense :thumbsup: