Have you looked at art.220.61?I am a little confused on the proper way to size a neutral feeder or service conductor. I think I understand the optional method from annex D but the standard method example D1(a) in Annex D , I'm not sure of. Can some one show me an example of both please?
Regarding range and dryer loads, think about it... how much current do they contribute to the neutral when unbalanced by another circuit? They are basically line-to-line loads... and that is only if their heat source is electric. A good way to determine the neutral current is to compare to gas-heated ranges and dryers.So is that all there is to it. Just add the general lighting load, small appliance load,laundry load and then 70% of the range and dryer? what about dishwasher, trash compactor, garbage disposal, deep freezer, central vac system window ac units ect. Please give me more input.
Regarding range and dryer loads, think about it... how much current do they contribute to the neutral when unbalanced by another circuit? They are basically line-to-line loads... and that is only if their heat source is electric. A good way to determine the neutral current is to compare to gas-heated ranges and dryers.
The gist of it is if you turned off all but one line on at a time, the maximum possible neutral current that any one line would place on the neutral is the maximum unbalanced neutral current.
If there is a panel schedule which includes (k)VA per circuit per line, just add up each line skipping over the line-to-line loads to get a total, add in your range and dryer amount, and whichever line totals the most line-to-neutral load is the maximum amount of unbalanced neutral current.