Conductor Insulation, NEC 2020 - [310.4], (19min:06sec)

Factors that impact conductor sizing include not only conductor ampacity and equipment terminal temperature rating, but also the conductor insulation temperature rating. In this video we discuss Table 310.4(A) which provides information on conductor insulation properties such as letter type, maximum operating temperature, application, insulation, and outer cover properties.
This video is an extract from Mike Holt’s Electrical Calculations Training Library, based on the 2020 NEC. For more information about this product visit www.MikeHolt.com/examprep or call 888.632.2633.
For over 40 years, Mike Holt Enterprises has been providing quality electrical code training to help electrical professionals learn the Code, prepare for exams, and improve their electrical knowledge. Visit www.MikeHolt.com for exam preparation tips and training, instructor and curriculum support, continuing education options, free videos and graphics, and so much more.

[@buddy6819]

Thanks so much Sir Mike Holt, be safe always, God bless

[@MikeHoltNEC]

Thank you!

[@davidredpath4781]

Awesome, Mike! Thank you!

[@MikeHoltNEC]

My pleasure!

[@abdullaalmamun7102]

Thank you so much Sir great full video sharing for us. It is very helpful learning points NEC 2020

[@pauloconnell7668]

Mike, Hard and Extra Hard usage-Think construction sites also.

[@trespire]

In metal work shops / manufacturing, flex cable doesn't hold up very well. Stepped on by work boots with metal chips in the soles, sheet metal scrap on the floors are like knives.

[@victorco.6308]

Very informative

[@MikeHoltNEC]

Glad you think so!

[@trilliondollarmogul5978]

The next generation.

[@peterdiamond5677]

What is ampacity rating of #12 AWG Copper THWN-2 at 60 Degrees Celsius?

[@MikeHoltNEC]

See Table 310.16 in the 2020 NEC or Table 310.15(B)(16) in the other Code books.

[@peterdiamond5677]

@@MikeHoltNEC I see the ampacity rating of #12 AWG Copper THWN-2 in 310.16 under 90 Degrees Celsius ONLY?

[@MikeHoltNEC]

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[@ecospider5]

The statements on the nylon jacket was not clear. It sounded like if the nylon cover came off when pulling it that was ok. How can that be if when you enter a box you have to have the nylon cover enter the box a certain distance. This statement could have used some more clarification.

[@MikeHoltNEC]

The nylon jacket is 'not' insulation, so if it gets damage or comes off, that is fine.

[@carultch]

For the most common applications, it is OK if the nylon jacket comes off during the pull. The nylon will absorb the wear and tear, so the insulation beneath it remains intact. It also reduces the friction, from what it would be, if the PVC insulation were the only layer surrounding the conductor. In applications where you need protection from gasoline, oil and chemicals, that is where you need to be careful not to damage the nylon jacket.

[@ecospider5]

That makes it sound like if you are going just a couple feet inside of a 2x4 wall you don’t actually need to use romex. You can just put in individual wires. White, black, and copper. Am I understanding this right or am I not understanding what the nylon jacket is.

[@carultch]

​@@ecospider5 It's a different kind of jacket, than the jacket that is on Romex. Individual conductors are typically required to be in a raceway or enclosure, unless otherwise permitted in the NEC. The nylon jacket on THWN-2 is very thin, and does not serve the same purpose as the jacket on a multiconductor cable.

[@MikeHoltNEC]

@@ecospider5 you can't run wires without being installed in a raceway or cable, see NEC 300.3(A).