ECN Forum Forums Code Related Discussion NEC & other Code issues 30 Amps on #14 AWG !@#$%

I agree with you about not causing a fire. After all, the ampacity per 310-16 is actually 25 amps (90 deg.column). However, I have felt(by hand) noticeable heat on a #12 that was running a continuous 18 amps.

Redsy,
You will feel heat. You have to remember that when you load a conductor to its full NEC ampacity, the conducotr will operate at the temperature in the ampacity table. 60°C is 140°F and that is hot to the touch.
Don

I agree with Don(resqcapt19).
Check out this graphic.

1999 NEC Code Graphic
Branch Circuit Tap Conductors, Section 210-19(d) Exception 1c
Understanding the 1999 National Electrical Code- (29KB) 2/7/00
http://www.mikeholt.com/graphics/210-19dx1c.gif

[This message has been edited by Mike W (edited 08-18-2001).]

Sorry, I made a fat finger.
Title of graphic is :
Branch Circuit Tap Conductors, Section 210-19(d) Exception 1c
Understanding the 1999 National Electrical Code- (29KB) 2/7/00

You can legally load a #14 thhn conductor to 35 amps. In Table 310-16, If the conductor is operating in an ambient temperature between 70-77 degrees F. or 21-25 C. You can appy a correction factor of 1.4 to the 25 amps under the 90 degree column. Although the LoadCenter probably wouldn't be operating in this environment, and all conductors must be sized to highest temperature it will see, but the code does show that we can use this formula for derating. Am I wrong here?

The asterisk in T310-16 refers to 240-3 which limits OCPD to 15 amps for #14. The exceptions don't include general purpose branch circuit wiring, which I believe is the idea in this thread. When using #14, The 90 deg. column is only usable for derating purposes, but still won't allow higher ampacity due to 240-3(d).



[This message has been edited by Redsy (edited 09-15-2001).]