Does anyone have a resource for calculating large multi-family dwelling units other than the NEC? It's been awhile for me and I am referring back to my Master's Block Test material and things aren't clicking yet. The examples in the NEC don't identify the derating clearly enough for me. I have a 76 unit complex with 1, 2 and 3 BR units and the entire project is electric everything, no gas appliances.
Here's what I got for one 1,500 sq. ft. condo. All condo's have the same items, just more or less sq. footage and a slightly different heating load:
Unit Sq. Ft x 3 for lighting, receptacle loads so 1500 sq.ft x 3 = 4.5kw
Small appliance loads, 2 x 1500 = 3 kw
Laundry load = 1500w
Dishwasher = 1200w
Water Heater = 4000w
Disposal = 1176w
Dryer = 5000
Microwave?
I am using the electric heating load given to me by the HVAC contractor of 14.4 kVA, large load due to high ceilings and old single pane glass windows. Since this is such a large load, the smaller condensing unit doesn't apply.
My problem is when and where to derate these loads. Should I use the optional method and derate each condo and then add them all up?
Should I use 220.84 and add all of the loads in the condo and then de-rate the entire service?
Thanks for any help.
Mike
Here's what I got for one 1,500 sq. ft. condo. All condo's have the same items, just more or less sq. footage and a slightly different heating load:
Unit Sq. Ft x 3 for lighting, receptacle loads so 1500 sq.ft x 3 = 4.5kw
Small appliance loads, 2 x 1500 = 3 kw
Laundry load = 1500w
Dishwasher = 1200w
Water Heater = 4000w
Disposal = 1176w
Dryer = 5000
Microwave?
I am using the electric heating load given to me by the HVAC contractor of 14.4 kVA, large load due to high ceilings and old single pane glass windows. Since this is such a large load, the smaller condensing unit doesn't apply.
My problem is when and where to derate these loads. Should I use the optional method and derate each condo and then add them all up?
Should I use 220.84 and add all of the loads in the condo and then de-rate the entire service?
Thanks for any help.
Mike