Ambient Temperature Adjustment Question 3

[deedo1124]

Designing some motor feeders that are routed in rigid steel conduit on an outdoor piperack. I am confused as what to use for the ambient temperature to determine if ampacity adjustment is required. Should I use the warmest average summer monthly high temperature, the areas record high temperature record, or other.

Thanks

 

[wareagle]

Where are you located?

 

[deedo1124]

The project is located in San Antonio. The motors are large 480V gas compressors and vacuum pumps.

 

[alehman]

NEC 310.15..2.c (2008) applies to roof installations but may offer some guidance.

Alan
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"It’s always fun to do the impossible." - Walt Disney

 

[wareagle]

This may help.

http://www.copper.org/applications/electrical/building/derating_table.html

 

[wareagle]

deedo1124

How about a response.

 

[deedo1124]

Wareagle

Thanks for the link. This will be very helpful.