[Electrical] Setting different demand factor/load class at the panel

[justin.wolters]

Good day all,

I'm working on a multi-story residential project where we're using NEC 2017 220.82's optional method to calculated the total demand for the individual unit panels, but want to use 220'84's method for calculating the demand factor from the unit panels to the distribution panels. It seems in revit we are only able to set the demand factor once at the individual connections/elements for receptacles, equipments and whatnot. Does anyone know of a way to "change" the demand factor/load classification that used when going a level "up" in a circuit?

Thanks!

[Dynamically_Static]

Automatically no, not that I am aware of.  Your not actually changing the demand factor, your trying to place a demand factor on top of a demand factor.

Your easiest step forward, in my opinion, is unfortunately a manual step.  Create a “hidden” fixture element / load for each dwelling unit that is set equal to the load summation of each dwelling unit and then a new demand factor compliant with the NEC article you referenced applied to those.

dynamo could easily transfer the info but two schedules placed back to back to ensure the data is easy to correlate and check in the future would be easy enough as well.

[justin.wolters]

That method of using a dummy load with the total connected load applied is what we're doing right now, which while results in the correct calculation for the unit panel(s), does not use the desired demand factor for the distribution panel calculations. I've attached a photos which hopefully outlines what's going on.

For the time being we're moving ahead with some good ol' fashioned Excel panel schedules, but we're still hoping to find a solution to this in Revit for future projects 

[fabiosato]

Hello,

Unfortunately, Revit does not operate as you wish.

[sragan]

I hope you (or your engineer) realize you can't use both 220.82 and 220.84 to calculate the loads for the distribution panel.

220.84(C) The calculated loads to which the demand factors of 220.84 apply shall include the following......

You don't get to apply one demand factor to the house panel and then another demand factor to the distribution panel.

[Dynamically_Static]

I do not design a lot of residential, so I wasn't going to say anything... but since you did... I kind of concur based on my limited understanding of that book.  It is not the forum or space to discuss electrical code issues, so I'll leave it at that!