Your service or feeder conductors must have a 100A capacity or more in order for you to be able to use the optional method in your calculation. If they are less, you must use the standard method (Part III of Article 220).
Unfortunately, I'm still developing my website. At the moment, the best way to get the tables is to screenshot and print the black and white copy that I put at the end of each Deep Dive video. Eventually, I'll have the tables made into fillable spreadsheets. That way you can just input the data and it'll auto calculate. Sorry for the wait!
Could you please confirm the service size and conductor size 1- 110 amp 110 OCPD with 3 awg cu CONDUCTORS 8 awg cu GEC 2- 133 amp 150 OCPD with 1 awg cu conductors and 6 awg cu GEC 4- 262 amp 300 OCPD With 250kcmil cu conductors 2 awg cu GEC
Do you mean EGC instead of GEC? The GEC depends on what type of grounding electrode you have (250.66(A&B). See Table 250.122 for EGC sizing. #1 - 110A = 110A OCPD, #3 cu, #6 cu EGC #2 - 132A = 150A OCPD, #1 cu, #6 cu EGC #4 - 262A = 300A OCPD, 250kcmil cu, #4 cu EGC
Thank you for your response. I was just generally using 250.66 to size GEC. (Understood that rod only requires 6 awg maximum and concrete encased electrode would require only up to 4 awg)
Since this is the Optional Method, almost everything is taken at nameplate value. Check out this video for a thorough explanation of the Optional Method. th-cam.com/video/pjSYPcfyKx0/w-d-xo.html
IN EX #1 AFTER APPLYING LOAD FACTOR WHICH IS 65% YOU SHALL COMPARE THE RESULT WITH 7200 WAT HEAT PUMP THE LARGEST ONE IS 7200 WATT INSTEAD OF 7200 WAT .REF:220.82.C.1-6 THANKS
Good catch! You're right. We need to take the largest load of the options provided in 220.82(C). And in this particular case, that would mean taking the heat pump at full value (7200VA vs 7150VA [11,000 x 65%]). This gives us a total of 26,360VA for the dwelling. Our total amps does not change with such a small revision and remains 110. Thanks for pointing that out! I will make a note in the video pronto.
![Ampacity Table, NEC 2020 - [310.15], (13min:26sec)](/img/n.gif)
What does it mean the 100A or greater on 220
82(A)?
Your service or feeder conductors must have a 100A capacity or more in order for you to be able to use the optional method in your calculation. If they are less, you must use the standard method (Part III of Article 220).
Im hoping to download your calculation tables to help work through them. Is that possible?
Unfortunately, I'm still developing my website. At the moment, the best way to get the tables is to screenshot and print the black and white copy that I put at the end of each Deep Dive video.
Eventually, I'll have the tables made into fillable spreadsheets. That way you can just input the data and it'll auto calculate. Sorry for the wait!
Excelente video!!!!
Thank you! Glad you found it helpful.
Could you please confirm the service size and conductor size
1- 110 amp 110 OCPD with 3 awg cu CONDUCTORS 8 awg cu GEC
2- 133 amp 150 OCPD with 1 awg cu conductors and 6 awg cu GEC
4- 262 amp 300 OCPD With 250kcmil cu conductors 2 awg cu GEC
Do you mean EGC instead of GEC? The GEC depends on what type of grounding electrode you have (250.66(A&B).
See Table 250.122 for EGC sizing.
#1 - 110A = 110A OCPD, #3 cu, #6 cu EGC
#2 - 132A = 150A OCPD, #1 cu, #6 cu EGC
#4 - 262A = 300A OCPD, 250kcmil cu, #4 cu EGC
Thank you for your response. I was just generally using 250.66 to size GEC. (Understood that rod only requires 6 awg maximum and concrete encased electrode would require only up to 4 awg)
@@Profanity42069 Right on. GEC sizing tends to trip a lot of people up, so I thought I'd mention it just in case.
Why aren’t you adding in 125% of largest motor?
Since this is the Optional Method, almost everything is taken at nameplate value. Check out this video for a thorough explanation of the Optional Method.
th-cam.com/video/pjSYPcfyKx0/w-d-xo.html
IN EX #1 AFTER APPLYING LOAD FACTOR WHICH IS 65% YOU SHALL COMPARE THE RESULT WITH 7200 WAT HEAT PUMP THE LARGEST ONE IS 7200 WATT INSTEAD OF 7200 WAT .REF:220.82.C.1-6 THANKS
Good catch! You're right. We need to take the largest load of the options provided in 220.82(C). And in this particular case, that would mean taking the heat pump at full value (7200VA vs 7150VA [11,000 x 65%]). This gives us a total of 26,360VA for the dwelling. Our total amps does not change with such a small revision and remains 110.
Thanks for pointing that out! I will make a note in the video pronto.