Temp adj.

[Alwayslearningelec]

If you have conduit and wire ran outdoors(where temp fluctuates throughout year bet 30deg and 95deg F) for an extended length say 300’ , do you need to adjust conductor ampacity? If so how would you do that with unknowns such as weather? Thanks

 

[Fred B]

Temperature is always a consideration no matter the length of conductors and may require de-rating depending on your calculation of temperatures applicable. Conductor length consideration of voltage drop also might come into play. Look at Article 310 for the calculations criteria.

 

[retirede]

Good explanation found here:

https://www.ecmag.com/section/codes-standards/sizing-conductors-part-xiv

 

[infinity]

Given the parameters in the OP with 90° C conductors I think you can pretty much ignore any corrections.

 

[Strathead]

Given the parameters in the OP with 90° C conductors I think you can pretty much ignore any corrections.

However, that would require THHN-2 or XHHW-2 THHN/THWN would require using the 75 degree table because it is a wet location.

 

[infinity]

However, that would require THHN-2 or XHHW-2 THHN/THWN would require using the 75 degree table because it is a wet location.

That's correct. I think that we're getting to the point where any new conductor will have 90°C wet or dry insulation.