Explanation of 310.15(B): How and why to use ambient temperature correction factors to determine conductors' new ampacities in hot or cold environments.
Believe it or not, your emphatic hand gestures and deliberately slow monologue are actually helpful in shoving this content into my brain pan. You deliberately walk through each sentence in the code, slowly, allowing me to follow in my 2023 NEC. You're doing a good job, and thank you.
I may have hit the wrong button on the stake. The reason why this doesn't have hundreds of thousands of subscribers is because this new generation is stupid. They don't realize the value, the intelligence and experience that this man has.
People will only learn if you tell them about this subject in a language they can understand, I asked 1000s of teachers why they don’t teach certain subjects, there attitude is, students don’t need to learn it, one really good teacher said, if you want to learn that go to the library, so help this guy make a book / video and publish it in the library, what do you think about my idea to help this guy ?
Firstly, these videos are wonderful, thank you Dave. Just want to add info for another common problem, and explain language in 110.14(C). You're feeding a >100A HVAC circuit on a rooftop, conduit is exposed to the sun and you want to adjust the ampacity for a higher temperature. You want to take advantage of 90C rated conductors, but the source panelboard and disconnect terminals are only rated for 75C. Calculate the allowable ampacity using the 90C column with your temperature correction. Then compare it to the ampacity rating of the 75C without temperature adjustments. If the 90C figure has a lower allowable ampacity than the 75C figure, then that wire size can be used. If the 90C figure was higher than the compared 75C, then the wire is too small.
I passed all of the IRC code exams, B1, P1 and M1 on first attempt. I failed by one question on the first attempt taking the IRC E1 exam. There were a few questions regarding Temperature Correction Factors for conductors that I got wrong. But now that I have found the Dave Gordon videos, WOW!!! I have to say Dave, you are amazing! Explained in perfect easy to understand format. Now I will use your videos to learn to pass the IRC E1 exam on my next attempt, thank you.
So I’m taking my test as well and I failed it because I missed every question regarding this damn section. By any chance do you remember a question regarding this?
Hi Dave. Your video is the best video I've come across on this topic! Definitely described the concepts well! It's unfortunate that the code update limited the ampacities to that of "60 deg C". I wish it had simply stated the actual maximum ampacity (perhaps being redundant in repeating the ampacity values off of the 60 deg column) values per wire gauge. The use of the "60 deg C" column is really confusing. I was left with the question: "Is NM-B 90 deg C cable, or 60 deg C cable???". I now understand NM-B is 90 deg C cable, and all correction factors for ambient temperature and conductor bundling are with respect to 90 deg Cable! This would be the end of the story, but the NEC folks decided to add an upper ampacity limit as per the 60 deg C values. It's just an added on upper limit (and an important one). I suspect this was to deal with some corner cases that are not often addressed explicitly. You already mentions attics in the summer, but other unknowns might be NM-B cable fished through insulated walls... How well is the cable heat dissipated when buried in insulation??? This 60 deg C upper ampacity limit likely catches this situation pretty well too. Anyway, thanks for the great video!
Finally i have found a video the properly explains this... I have had several electricians and web searches and other videos stating that you always adjust on the 90 degree column... I am new to learning this and that never made sense... mainly because there was also a 60 and 75 degree column... I'm starting to think a lot of things people say are based on "well that's just how do it" as opposed to "this is what the book says" and here it is... great content!
plus thank you for explaining things to me that I should already know. You are a rockstar and I will watch more of your videos and share them with other tradesmen. Edit: subscribed
Dave...thank you SOOOOOO much for this video and a the few additional I already have discovered today by just finding you. You area true blessing to the world of electrical contractors and enthusiasts who want to know and follow the code to the letter! You are a true Gentleman and a Master! Example Question - If you run a 90C 6/3 NM-B wire in a location of Ambient Temp of 30C to a junction box in that location BUT then come out of that junction and right into a space 10 ft away that has an ambient temp of 70C with 4/3. Do I only adjust amperage based on the higher heat on the 4/3 (since its the wire size in the higher heat) or do I have to perform my adjustments based on 6/3 (since this feeds the circuit at the junction box in the lower heat)? Thank you if you can please make this clear!
What about some people say when ampacity is corrected by temperature and ajustmente, is not necessary to apply: 110-14 (c), 60C column for 100A or less circuits. ¿Is it true?
does the calculated roof top temperature become the “ambient” temperature, needing only one temperature correction or do we do two calculations 1 for ambient, one for distance from roof?
But in 240.4(D) Small Conductors you can also find, Unless otherwise specifically permitted in 240.4(E) or 240.4 (G), the overcurrent protection shall not exceed 15 amperes for 14 AWG, 20 amperes for 12 AWG, and 30 amperes for 10 AWG copper; or 15 amperes for 12 AWG and 25 amperes for 10 AWG aluminum and copper-clad aluminum after any correction factors for ambient temperature and number of conductors have been applied. It looks like this statement omit the insulation types, for example #14 AWG copper can only carry 15 A at most, no matter what kind insulation it is. Please help me to understand this, thanks!
With the increase in outside temp. the current going through the conductor decreases due to increase in the resistance. But why with the increase in the temperature allowable ampacity is increasing? As it is varying from 60 to 75 to 90.
You are correct in your initial sentence that as the ambient air temperature increases, the conductor will heat up and therefore make it harder for current to flow due to the increase in conductor resistance as temperature rises. If I understand your question correctly, you are wondering why the allowable ampacity increases as the temperature rating of a conductor increases. The conductor's temperature rating is based on the type of insulation surrounding the copper or aluminum. As current flow increases, the internal temperature of the conductor increases and if it gets hotter than the insulation is rated for, the insulation will start to breakdown. Some insulation types can stand up to higher temperatures than others and therefore conductors with higher rated insulations are allowed to carry more current than the same size conductor with a lower rated insulation. It's about protecting the insulation. If you haven't seen my other videos on conductors, they may be helpful and the playlist can be found at ua-cam.com/play/PLxFqFitetEACd7sAoHvXGQqIHWjmLxl41.html
![Ampacity Table, NEC 2020 - [310.15], (13min:26sec)](/img/n.gif)
Believe it or not, your emphatic hand gestures and deliberately slow monologue are actually helpful in shoving this content into my brain pan. You deliberately walk through each sentence in the code, slowly, allowing me to follow in my 2023 NEC. You're doing a good job, and thank you.
This channel should have hundreds of thousands of subscribers. It’s a hidden gem.
I may have hit the wrong button on the stake. The reason why this doesn't have hundreds of thousands of subscribers is because this new generation is stupid. They don't realize the value, the intelligence and experience that this man has.
People will only learn if you tell them about this subject in a language they can understand, I asked 1000s of teachers why they don’t teach certain subjects, there attitude is, students don’t need to learn it, one really good teacher said, if you want to learn that go to the library, so help this guy make a book / video and publish it in the library, what do you think about my idea to help this guy ?
@@genebowdish.mageniemagic videos are easier to understand
This guy is one of the best teachers I ever had. Proudly LU 46
I’m IBEW local 38. I watch his videos a lot. I’ve been in the trade 25 years. He can explain things very well!!
This man is saving my career singlhandedly
Firstly, these videos are wonderful, thank you Dave. Just want to add info for another common problem, and explain language in 110.14(C).
You're feeding a >100A HVAC circuit on a rooftop, conduit is exposed to the sun and you want to adjust the ampacity for a higher temperature. You want to take advantage of 90C rated conductors, but the source panelboard and disconnect terminals are only rated for 75C.
Calculate the allowable ampacity using the 90C column with your temperature correction. Then compare it to the ampacity rating of the 75C without temperature adjustments. If the 90C figure has a lower allowable ampacity than the 75C figure, then that wire size can be used. If the 90C figure was higher than the compared 75C, then the wire is too small.
Thank you for the clarification. Can you also do this for temperatures lower than the 30C?
I have to say that this is the Best Explanation of this. He made it simple to understand. Answers all the questions u might have. Amazing teacher
All that was needed was the gong sound at the end of this masterpiece! Great presentation and thank goodness for material like this. Glad i subscribed
Subscribed, liked, notifications on all, sharing and writing a comment. Very good content
I passed all of the IRC code exams, B1, P1 and M1 on first attempt. I failed by one question on the first attempt taking the IRC E1 exam. There were a few questions regarding Temperature Correction Factors for conductors that I got wrong. But now that I have found the Dave Gordon videos, WOW!!! I have to say Dave, you are amazing! Explained in perfect easy to understand format. Now I will use your videos to learn to pass the IRC E1 exam on my next attempt, thank you.
So I’m taking my test as well and I failed it because I missed every question regarding this damn section.
By any chance do you remember a question regarding this?
Great video. The best temperature correction factors video I’ve seen. Thank you.
Hi Dave. Your video is the best video I've come across on this topic! Definitely described the concepts well! It's unfortunate that the code update limited the ampacities to that of "60 deg C". I wish it had simply stated the actual maximum ampacity (perhaps being redundant in repeating the ampacity values off of the 60 deg column) values per wire gauge. The use of the "60 deg C" column is really confusing. I was left with the question: "Is NM-B 90 deg C cable, or 60 deg C cable???". I now understand NM-B is 90 deg C cable, and all correction factors for ambient temperature and conductor bundling are with respect to 90 deg Cable! This would be the end of the story, but the NEC folks decided to add an upper ampacity limit as per the 60 deg C values. It's just an added on upper limit (and an important one). I suspect this was to deal with some corner cases that are not often addressed explicitly. You already mentions attics in the summer, but other unknowns might be NM-B cable fished through insulated walls... How well is the cable heat dissipated when buried in insulation??? This 60 deg C upper ampacity limit likely catches this situation pretty well too. Anyway, thanks for the great video!
Finally i have found a video the properly explains this... I have had several electricians and web searches and other videos stating that you always adjust on the 90 degree column... I am new to learning this and that never made sense... mainly because there was also a 60 and 75 degree column... I'm starting to think a lot of things people say are based on "well that's just how do it" as opposed to "this is what the book says" and here it is...
great content!
Thank you for the clear and concise explanation. Cheers mate.
The best information I ever had
Probably the best nec teaching video out there.
plus thank you for explaining things to me that I should already know. You are a rockstar and I will watch more of your videos and share them with other tradesmen. Edit: subscribed
This video answers a lot of questions
Love the way u explain
You have a great delivery
Very impressive way of teaching 👍
Thank you for the very clear explanation. It answers lots of my questions.
Good job Dave!
Great video.
you are a very good teacher . thank you !!!!
Salute! Good explanation, would like to see more examples.
Thank you! Very helpful
Thank you for information you are sharing it here, it is really useful
Dave...thank you SOOOOOO much for this video and a the few additional I already have discovered today by just finding you. You area true blessing to the world of electrical contractors and enthusiasts who want to know and follow the code to the letter! You are a true Gentleman and a Master! Example Question - If you run a 90C 6/3 NM-B wire in a location of Ambient Temp of 30C to a junction box in that location BUT then come out of that junction and right into a space 10 ft away that has an ambient temp of 70C with 4/3. Do I only adjust amperage based on the higher heat on the 4/3 (since its the wire size in the higher heat) or do I have to perform my adjustments based on 6/3 (since this feeds the circuit at the junction box in the lower heat)? Thank you if you can please make this clear!
Great instructor
Well explained. Thanks so much.
Thank you good sir for your hard work 🎉
Thank you 🙏
Thanks again...
Worth noting that there is an exception in the code that states when using XHHW-2 conductors they don’t have to be corrected.
helpful video thank you
What about some people say when ampacity is corrected by temperature and ajustmente, is not necessary to apply: 110-14 (c), 60C column for 100A or less circuits. ¿Is it true?
thanksssss a lotttt!
does the calculated roof top temperature become the “ambient” temperature, needing only one temperature correction or do we do two calculations 1 for ambient, one for distance from roof?
Are your lectures available in sequence on LinkedIn?
What ambient temperature should be used for directly buried raceway/cables?
what about adding 60 degree terminals into the mix with 90 degree conductors going through a boiler room at 121 degrees?
But in 240.4(D) Small Conductors you can also find, Unless otherwise specifically permitted in 240.4(E) or 240.4 (G), the overcurrent protection shall not exceed 15 amperes for 14 AWG, 20 amperes for 12 AWG, and 30 amperes for 10 AWG copper; or 15 amperes for 12 AWG and 25 amperes for 10 AWG aluminum and copper-clad aluminum after any correction factors for ambient temperature and number of conductors have been applied. It looks like this statement omit the insulation types, for example #14 AWG copper can only carry 15 A at most, no matter what kind insulation it is. Please help me to understand this, thanks!
do I still need to add 25% for things that run a long time?
super👌👌👌
Is there ever a case where you would use the 75*C column for a 90*C rated cable?
Check out the post I just made for the video, it should answer this quesiton.
@@crazyskier66 im sorry, where do i find the post?
110.14 (c)
wich column should we use 60, 75 , 90 ?
It’s based off your wiring temp rating in table 310.4
With the increase in outside temp. the current going through the conductor decreases due to increase in the resistance. But why with the increase in the temperature allowable ampacity is increasing? As it is varying from 60 to 75 to 90.
You are correct in your initial sentence that as the ambient air temperature increases, the conductor will heat up and therefore make it harder for current to flow due to the increase in conductor resistance as temperature rises.
If I understand your question correctly, you are wondering why the allowable ampacity increases as the temperature rating of a conductor increases. The conductor's temperature rating is based on the type of insulation surrounding the copper or aluminum. As current flow increases, the internal temperature of the conductor increases and if it gets hotter than the insulation is rated for, the insulation will start to breakdown. Some insulation types can stand up to higher temperatures than others and therefore conductors with higher rated insulations are allowed to carry more current than the same size conductor with a lower rated insulation. It's about protecting the insulation.
If you haven't seen my other videos on conductors, they may be helpful and the playlist can be found at ua-cam.com/play/PLxFqFitetEACd7sAoHvXGQqIHWjmLxl41.html
Where in the world have you been in my entire career...?
Still confused.
Thank you for sharing your knowledge and experience 🇵🇭🫡
Always keep safe and in good health ❤️
In other words, derating is all about ambient temperature and that’s it