mielectric1
Member
I am very familiar with 220.84, been using since before it was called 220.84.
But typical to multi -family electric range and AC ware present.
Here is the new twist, multifamily with no range, now I understand that I can still use 220.84 (if I add and extra 8kw for a non existant range) and if that is less than part III I can use the lesser.
Heres my gripe, when calcing with part III I get 1300 amps, and with 220.84 1075 amps. (again I know I can use the 1075) but call me crazy, but how can a calc that is intended for AC AND a RANGE be lower than a calc with no range?!?!?!?!
It seems to me that there should be a demand factor applied to the AC load of a multifamily just like there is a demand factor applied to AC and range with 220.84.
I went through 430 but I fail to see a formula for calcing loads of multiple motors on meter banks as in a multifamily arrangement.
I am aware of 430.26 stating that the AHJ can allow a lesser ampacity, but where is an example of such demand factor derating.
It just stands to logic, if a calc with ranges and ACs is 1075, then with no ranges it should be less not more, say around 850 or so.
BTW if I use 220.84 without the 8kw for ranges it comes up to 755amps
3 phase 120/208
let me know what you think.
But typical to multi -family electric range and AC ware present.
Here is the new twist, multifamily with no range, now I understand that I can still use 220.84 (if I add and extra 8kw for a non existant range) and if that is less than part III I can use the lesser.
Heres my gripe, when calcing with part III I get 1300 amps, and with 220.84 1075 amps. (again I know I can use the 1075) but call me crazy, but how can a calc that is intended for AC AND a RANGE be lower than a calc with no range?!?!?!?!
It seems to me that there should be a demand factor applied to the AC load of a multifamily just like there is a demand factor applied to AC and range with 220.84.
I went through 430 but I fail to see a formula for calcing loads of multiple motors on meter banks as in a multifamily arrangement.
I am aware of 430.26 stating that the AHJ can allow a lesser ampacity, but where is an example of such demand factor derating.
It just stands to logic, if a calc with ranges and ACs is 1075, then with no ranges it should be less not more, say around 850 or so.
BTW if I use 220.84 without the 8kw for ranges it comes up to 755amps
3 phase 120/208
let me know what you think.