Temperature Correction of Ampacity

Ampacity Correction
Temperature Correction
Continuous Load Correction
Conduit Fill Correction
Minimum Number of Circuits
Bus Bar Ampacity
Conductor Resistance
Resistance Change
Motor Disconnect Sizing
Full Load Current Interpolation
Motor Conductor Sizing
Motor Overcurrent Protection
Motor Overload Sizing
Lighting Loads
Fixed Appliance Loads
Range Loads
Range Loads Note 1
Range Loads Note 2
Dryer Water Heater Loads
Heat AC
Standard Residential Service
Optional Residential Service
Standard Multi Family Service
Optional Multi Family Service
Commercial Services
Optional School Services
NEC Calculations Home
Electrician Math Home
Electrician Education Home

Where a conductor is expected to occupy a space where the surrounding (ambient) temperature will exceed 86 degrees Fahrenheit, then a reduction (derating) in the table ampacity will produce the corrected ampacity for that specific use.

Temperature correction is ALWAYS made based on maximum temperature (over 86 degrees F) the conductor will encounter on its travel from source to load.

Example: What is the corrected ampacity for a #2 THWN copper conductor expected to pass through a maximum temperature of 100 degrees F?

Solution: The table ampacity of this conductor is 115 amps. Follow down the table 310.16 to find the correction factor for temperature of .88. Then multiply these two numbers together.

Result: The corrected ampacity for this specific use is 101.2 amps.

Find practice problems HERE.

Find audio support HERE.



Click on any of these titles from Amazon.com which may be of interest to you.
Order them directly from Amazon.com with a debit or credit card.


Many electrician workbooks and practice exams are now available 
as digital downloads for immediate use. 
Click HERE to see what is available.

Products For Sale
2006-2011 David U. Larson
Companion Website to ElectricianEducation.com ,
2011NEC.com and
Other websites by David U. Larson which may be of interest: