We take 125% of the largest motor (the 15HP in this case) and add it to 100% of all other motors per 430.24. This equals 88.55 amps. Using the 75 degree Celsius column of 310.15(B)(16), we see that in order to cover 88.55 amps we would have to go up to a #3 copper wire. Hope that helps!
nice video however NEC2020 430.32(A)1 doesn't it say that for the overload devices we shall use a percentage of the motor "NAMEPLATE" full-load current rating for overload devices, which comes from the "motor nameplate" and we use the FLC tables for the overcurrent devices. Mike Holt does a video on when to use nameplate and when to use tables. Also I'm not posting this to criticize anyone, I'm just trying to better understand what I was taught in the past.
Hello Daniel, Assuming the nameplate on a motor is available and specifies an FLC, we would use the nameplate rating as a basis for all of our calculations. The tables (430.248 and 430.250) are used when we either don't have a nameplate, or the nameplate doesn't specify the FLC. This is because most motors are unique, and you may notice the verbiage used for the tables such as "normal" and "usual". They provide a good base-line when other information isn't available, but always go with the nameplate values when they are available. Hope that helped, and thank you for the comment!
@@electrical1019 Thanks for the reply, however I think more clarification is in order. Again I am just want to understand fully. I think the NEC makes a clear distinction between motor nameplate values and table values and when to use them. How I understand it so far is the table values are more extreme, sort of worst case scenario numbers they came up with from years of data, so they are used for sizing conductors and over-current devices, etc, while the motor overloads protect the motor so therefore when sizing overloads we use the actual nameplate value from the motor since motors are unique to properly protect the motor. In my experience the table values and nameplate values are always different and both are normally used in motor load calculations. NEC 2020 430.6, 430.6(A)(1)and elsewhere it states that table values are used for conductors and same elsewhere for overcurrent devices. The 430.6(A)(2) states that motor nameplate values are used for sizing overload devices. Is this correct, generally speaking. I know there are exception when nameplate is missing or special duty cycles but that aside, I think the main point is both table values (conductors, overcurrent, etc) and motor nameplate values (motor overloads) are normally used for calculations.
here is a link to a good Mike Holt video from 2014 talking about the differences of the protection devices but also the values th-cam.com/video/nvJaaWGJMo0/w-d-xo.html
@@danielfagan7406 Sorry for the confusion, I believe I understand what you're asking now. I would point you to 430.6(A)(1) and (2), which I think summarizes up the information you're looking for. If not let me know though!
@@electrical1019 ok now we are getting somewhere. Those two articles that you cited are the same two that I cited in my previous response and they say to use motor nameplate for overloads and the tables for the other protection. That is also echoed in the Mike Holt video that I linked. So after reading those articles wouldn't you agree that your video is inaccurate because in it you used only table values to make all the calculations when in step 2 for overloads it should have been the motor nameplate flc for the basis of the calculation. Although you even say "nameplate flc" you are using the table value that you found in step 1/
HI there, I recommend ordering one directly from NFPA's website, but many electrical supply houses and regular book stores offer them as well. Hope that helps!
You incorrectly use the FLC for the Overload size. NEC 430.32(A)(1) explicitly states to use the nameplate value, "...shall be rated at no more than the following percent of the motor nameplate full-load current rating:"
I was with it until the table 430.52….if our FLC was 35.4/53.13…. And used the percentage of the time delay fuse being 175 %…. 35.4x1.75=61.98 FLC/ 53.13x1.75=92.97….. yet you came up with 53.9/80.89 FLC…. Anyone care to try and help me out perhaps…. Seems I spend hours working on these calculations and they just seem to not work out yet never a very good explanation of how they come to their answer…..
Hello, the FLC of our motors was not 35.42/53.13. 35.42/53.13 was the maximum size overload protection we could use for the motors based on 430.32. The FLC as determined by 430.250 for these motors was 30.8 and 46.2. If you multiply these values by the 175% from table 430.52 that you reference, then you will end up with 53.9 and 80.89. Hope that helps!
Actually you are right I have the same 35 .4 I found better to learn onhm law and just use this videos for a guide I did the same calculations and they are off by a lot I have 35.8 on 10 horse power at 208 volts
This is wonderful! I love the step by step method.
Thank you so much!
I agree great video. It explains code and calculations. Which is a great combination because many people won't understand the criteria
Great video. Thank you for the information.
Thank you! Glad to help!
Very helpful and to the point. Thank you.
Thank you very much! Glad to help!
i havent heard that name in a very ..very long time.... SFMF
Can you please tell me why the motors doens't have any starter. I leaned dol can use maximum 5hp..
Thank you very much for sharing.
Thank you!
step 5 was not clear on how #3 AWG was selected ?x125%?
We take 125% of the largest motor (the 15HP in this case) and add it to 100% of all other motors per 430.24. This equals 88.55 amps. Using the 75 degree Celsius column of 310.15(B)(16), we see that in order to cover 88.55 amps we would have to go up to a #3 copper wire. Hope that helps!
nice video however NEC2020 430.32(A)1 doesn't it say that for the overload devices we shall use a percentage of the motor "NAMEPLATE" full-load current rating for overload devices, which comes from the "motor nameplate" and we use the FLC tables for the overcurrent devices. Mike Holt does a video on when to use nameplate and when to use tables. Also I'm not posting this to criticize anyone, I'm just trying to better understand what I was taught in the past.
Hello Daniel,
Assuming the nameplate on a motor is available and specifies an FLC, we would use the nameplate rating as a basis for all of our calculations. The tables (430.248 and 430.250) are used when we either don't have a nameplate, or the nameplate doesn't specify the FLC. This is because most motors are unique, and you may notice the verbiage used for the tables such as "normal" and "usual". They provide a good base-line when other information isn't available, but always go with the nameplate values when they are available. Hope that helped, and thank you for the comment!
@@electrical1019 Thanks for the reply, however I think more clarification is in order. Again I am just want to understand fully. I think the NEC makes a clear distinction between motor nameplate values and table values and when to use them. How I understand it so far is the table values are more extreme, sort of worst case scenario numbers they came up with from years of data, so they are used for sizing conductors and over-current devices, etc, while the motor overloads protect the motor so therefore when sizing overloads we use the actual nameplate value from the motor since motors are unique to properly protect the motor. In my experience the table values and nameplate values are always different and both are normally used in motor load calculations. NEC 2020 430.6, 430.6(A)(1)and elsewhere it states that table values are used for conductors and same elsewhere for overcurrent devices. The 430.6(A)(2) states that motor nameplate values are used for sizing overload devices. Is this correct, generally speaking. I know there are exception when nameplate is missing or special duty cycles but that aside, I think the main point is both table values (conductors, overcurrent, etc) and motor nameplate values (motor overloads) are normally used for calculations.
here is a link to a good Mike Holt video from 2014 talking about the differences of the protection devices but also the values th-cam.com/video/nvJaaWGJMo0/w-d-xo.html
@@danielfagan7406 Sorry for the confusion, I believe I understand what you're asking now. I would point you to 430.6(A)(1) and (2), which I think summarizes up the information you're looking for. If not let me know though!
@@electrical1019 ok now we are getting somewhere. Those two articles that you cited are the same two that I cited in my previous response and they say to use motor nameplate for overloads and the tables for the other protection. That is also echoed in the Mike Holt video that I linked. So after reading those articles wouldn't you agree that your video is inaccurate because in it you used only table values to make all the calculations when in step 2 for overloads it should have been the motor nameplate flc for the basis of the calculation. Although you even say "nameplate flc" you are using the table value that you found in step 1/
Please how do I get code book 📚 for my self please
HI there, I recommend ordering one directly from NFPA's website, but many electrical supply houses and regular book stores offer them as well. Hope that helps!
Good information thanks
Thank you! Glad it helped!
Change playback speed to x1.25
Please take a drink. Or COUGH DROPS respectfully Excellent info but I find myself more focused on when he's coughing next.
You incorrectly use the FLC for the Overload size. NEC 430.32(A)(1) explicitly states to use the nameplate value, "...shall be rated at no more than the following
percent of the motor nameplate full-load current rating:"
Can you tell me why no starters are used here.. DOL starters can only use upto 5hp..
I was with it until the table 430.52….if our FLC was 35.4/53.13…. And used the percentage of the time delay fuse being 175 %…. 35.4x1.75=61.98 FLC/ 53.13x1.75=92.97….. yet you came up with 53.9/80.89 FLC…. Anyone care to try and help me out perhaps…. Seems I spend hours working on these calculations and they just seem to not work out yet never a very good explanation of how they come to their answer…..
FLC's were 30.8 and 46.2. It looks like you used FLC with the 115% overload adjustment. I've done the same thing
Hello, the FLC of our motors was not 35.42/53.13. 35.42/53.13 was the maximum size overload protection we could use for the motors based on 430.32. The FLC as determined by 430.250 for these motors was 30.8 and 46.2. If you multiply these values by the 175% from table 430.52 that you reference, then you will end up with 53.9 and 80.89. Hope that helps!
Actually you are right I have the same 35 .4 I found better to learn onhm law and just use this videos for a guide I did the same calculations and they are off by a lot I have 35.8 on 10 horse power at 208 volts
Great information but I can't pay attention cause of his coughing its just me cause it's a pet peeve 😢
First take care of that annoying cough before you post a 19 min video.