NEC Annex D

[Konen]

Can anyone help me understand a calculation in Annex D.

Example D4(b) Optional Calculation for Multifamily Dwelling

I thought using the optional calculation method, you do not apply the demand factor to general lighting or to the Range etc, until you have all loads except A/C or heat. Then apply T220.84, then add noncoincidental load. (Had to edit, I mis typed it, my brains all over the place )

 

[letgomywago]

You use the multifamily optional demand factors not the same as single family. Also take a look at 220.85 if you missed your admin exam by 1 question I know they have an optional duplex on there and you will want to look at that part of the code too.

Sent from my SM-S367VL using Tapatalk

 

[Konen]

Oh that's probably one that I missed, I remember they had (2) duplex questions on there. I completely disregarded T220.84 because the duplex questions sent my brain straight to Part III. I'm still not seeing anywhere in Section 220 of not using nameplate values for optional calculation method for Multifamily. Do you by chance have a code reference?

What I'm interpreting optional as is no demand factors until all loads (excluding noncoincidental load) are added together then apply T220.84 demand factor. Then add noncoincidental load.
Picture below is what I'm referencing.

 

[letgomywago]

You have the order right the question I had had you exclude "house loads" you go straight nameplate and lighting and heat/ac and then use your demand factor in table 220.84. The duplex you need to remember to multiply by 3 and then do the demand factor.

Sent from my SM-S367VL using Tapatalk