Conductor Sizing and Adjustment

[@Californians_go_home]

They changed the amp ratings in the 60 degree column in 2020.

[@MultilineDesignscom]

Excellent, well done video on a rather confusing topic.

[@parthikumar6683]

If the conductor is rated for 90°C and the motor's amp rating is less than 100 amps, then can we use the 90°C amp rating for cable sizing? Similarly, when the equipment is rated for 75°C but the cable is rated for 90°C, still use the equipment's 75°C amp rating for cable sizing calculations?

[@crosslolo7245]

Thank you JESUS finally someone to explain the why!🙄

[@Californians_go_home]

It doesn’t look like anybody responds here but I’ll ask anyway. Do multiple NM cables used as home runs using cable stackers, rated to hold up to 8 number 12 per manufacturer specification, have to be derated?? It says right on the package 8 number 12 and 8 number 14. Length of run is not specified, but it’s over 24 inches. Same applies for wall cavities that are insulated. Code says you can go my manufacturer specs. If I read the code right, nm cable rated at 90c is already derated based on amperage in the 60c column. 20 amp max number 12 and 15 amp max number 14. If that is true, 8 home runs could safely be used in a cable stack.

[@knotnyce]

No you would not derate for cable stackers, as they are not considered to be a conduit or raceway. Same goes for insulated wall cavities. Just bare in mind that NM/Romex cables are rated at 60 degrees and therefore all calculations should be based on that premise